Graduate Research Symposium

student research at jackson estuarine lab

Graduate Research Symposium

This Symposium is designed to showcase graduate student research, to build awareness of UNH marine research activities, and enhance interdisciplinary connections within the School of Marine Science and Ocean Engineering community.

This one-day Symposium is held every spring and traditionally includes a series of graduate student oral presentations, poster presentations, and concludes with an awards ceremony.

Any UNH Graduate Student with marine-focused research is invited participate in either an oral or poster presentations. We welcome all faculty, staff, students, and the general public to attend the event.

Free drinks and appetizers provided during the Poster Reception.

Event Details

Thurs, March 28, 2024
1:00 – 6:00 pm

Stillings Hall
   Conference Room
UNH Durham Campus


1:00 pm  Welcome
1:15 pm  Oral Presentations
3:30 pm  Poster Reception
5:00 pm  Awards Ceremony

2024 Event Schedule

Current Graduate Research Symposium Oral Presentations

Caroline Anderson, MS - Oceanography

The Role of Dissolved Organic Phosphorus Uptake in Satisfying Total Phosphorus Demand by Phytoplankton

Photo of student filling test tubes.

Phytoplankton form the basis of the marine ecosystem and require phosphorus (P) for growth. Typically, phytoplankton utilize inorganic phosphate (PO43-) as it is the more biologically available form of P. Many regions across the global ocean have been found to exhibit vanishingly low concentrations of PO43- including the subtropical North Atlantic and North Pacific. Dissolved organic phosphorus (DOP) has been shown to serve as an alternative P source when PO43- concentrations are low. However, the concentration of PO43- which leads to significant phytoplankton DOP uptake has not been widely established. Emiliania huxleyi (E. huxleyi) and Chaetoceros tenuissimus (C.tenuissimus) cultures were grown under five PO43- concentrations of increasing PO43- scarcity with an addition of DOP in each treatment. Measurements of alkaline phosphatase activity (APA), which is the enzyme used to access the P from DOP, and the consumption of PO43- and DOP were monitored over a 2-week period. Elevated APA rates were observed in the lowest PO43- treatments as expected. Growth rates for E. huxleyi were similar regardless of P source but C.tenuissimus unexpectedly grew faster when utilizing DOP compared to PO43-. C.tenuissimus also utilized DOP to satisfy a higher percentage of their P demand compared to E. huxleyi. Our experimental data suggest minimum DOP utilization rates for these two phytoplankton were 1.5 to 2.5 times greater than previous estimates, expanding the spatial domain over which this process may occur in the ocean.

Savannah Devoe, PhD - Ocean Engineering

Mobile sediment layer dynamics in nearshore environments 

Photo of a probe descending on a wavy surface.

In coastal environments, ripples and other small-scale bedforms can transport large volumes of sediment and thus are important drivers of net morphologic change. Our ability to observe and quantify this transport in the field, however, is often limited by available instrumentation, which can lead to low spatiotemporal resolution of the near-bed flow field and the resulting volume of sediment flux. This presentation will highlight recent efforts to improve estimates of sediment transport in cases where little information about the near-bed flow is known by coupling high-resolution observations of flow over mobile, rippled beds with observations of bedform response and bulk flow characteristics. The primary focus will be on results derived from a numerical Large Eddy Simulation (LES) and Discrete Particle Model (DPM), which was used to investigate the spatiotemporal evolution of the mobile sand grain layer and shear stress within a rippled bed. The main finding from this work is that estimates of time-dependent, spatially-averaged sediment transport derived from common existing methods are only comparable to observed transport if they utilize estimates of shear stress made directly at the ripple crest. Time-dependent transport cannot be estimated with existing methods using shear stress estimates made on the ripple slopes or in the ripple trough. The numerical simulation is then compared with high-resolution laboratory observations collected in the UNH Environmental Flows Water Tunnel (EFWT). The EFWT was used to conduct 21 experiments to explore the effect of varying ripple shape, wave period, and free-stream flow on our ability to estimate bed shear stress, mobile layer thickness, and sediment transport. Collectively, these efforts provide new insight into small-scale fluid-sediment interactions in nearshore environments that will lead to a more complete understanding of the morphologic evolution of sandy beaches. 

William Lush, PhD - Oceanography

Validating global dispersal estimates using GDP drifter trajectories

Patterns of dispersal in the coastal ocean are important for predicting the spread of marine pollutants, nutrients, and planktonic larvae. New high-resolution circulation models and Lagrangian particle tracking methods allow us to estimate dispersal pathways with unprecedented detail, but the small number of observations of dispersal pathways in the real ocean makes error estimates on these pathways quite difficult. In this work, I compute mean dispersal pathways using OceanParcels and velocity fields from the Mercator 1/12° global physical model. I compare these dispersal pathways to trajectories of drifters from the Global Drifter Program to determine how well global numerical estimates replicate real-world dispersal.

Grace McCulloch, MS - Natural Resources and the Environment

Preparing for the future: Understanding current Saltmarsh Sparrow (Ammospiza caudacuta) habitat in New Hampshire

Photo of student holding a bird in her fingers outside.

Accelerated sea level rise threatens salt marsh persistence and endemic wildlife, like the saltmarsh sparrow (Ammospiza caudacuta), that rely on this ecosystem. In New Hampshire, a new set of tools developed by Great Bay National Estuarine Research Reserve including the Saltmarsh Sparrow Habitat Prioritization Tool, the High-Resolution Tidal Wetlands Mapper and the NH Marsh Plan, guide where restoration is prioritized. While providing enhanced resolution and habitat priorities, none explicitly consider saltmarsh sparrow occupancy or nest presence. Our research seeks to identify the features that best predict this. Point count data from 86 locations are being used to rank marshes based on saltmarsh sparrow occupancy and relative abundance. Models for these response variables are being built with covariate data from the tools and field-based vegetation surveys. The locations of nests across NH salt marshes are being used to characterize key features of nesting sites, identifying differences from random points within the same marsh. Several key features include high resolution tidal wetlands cover, site specific water levels, and elevation. Together these findings will provide managers with the features that best predict saltmarsh sparrow occupancy across marshes and the location of nests within occupied marshes, providing greater context in tidal marsh management aimed at benefiting a species vulnerable to extinction. Applications include informing where and how restoration projects are implemented and restoration priorities at state and regional levels.

Grant Milne, PhD - Marine Biology / Acoustics

Comparing the Soundscapes of Coastal New England Marine Habitats

Passive acoustic monitoring is a valuable tool for habitat monitoring and assessment, though existing analysis techniques are often time consuming. The present study evaluated the utility of the Soundscape Code, a collection of metrics intended to enable rapid assessment of soundscapes, to determine whether habitat type or geographic location accounts for a greater amount of variability in the soundscapes of coastal Gulf of Maine habitats. Hydrophones were deployed in three different habitat types (sand, macroalgae, and eelgrass) containing varied acoustic propagative properties. These deployments were replicated in four different geographic locations along the Maine and New Hampshire coastlines. Hourly metrics representative of amplitude, impulsivity, uniformity, and periodicity calculated across five different frequency bands (10-100 Hz, 100-1000 Hz, 1-10 kHz, 10-144 kHz, and 10-144 kHz) were utilized for multivariate statistical analysis to draw direct comparisons between soundscapes. The analyses revealed that geographic location accounted for a greater amount of variability in soundscapes than habitat type. This suggests that there are high levels of acoustic connectivity between localized habitats, which highlights the importance of managing anthropogenic sound as well as the vital role that soundscapes play for orientation and communication among marine biota.

Mamun (Mamunur Rashid) Patwary, PhD - Mechanical Engineering

Hydrodynamic Modeling of Kelp Farms: From an Aggregate of Kelp to a Longline System

Photo of people pulling large clump of kelp onto front of boat.

Fredriksson et al. (2020) conducted tow tests in freshwater baths to investigate the drag characteristics of kelp. They employed a physical model of kelp rather than actual kelp, subjecting it to various towing velocities applied in parallel and perpendicular orientations to the kelp cultivation line: 0.25 m/s, 0.5 m/s, 0.75 m/s, 1.0 m/s, and 1.25 m/s. Subsequently,  Zhu et. al.(in preparation) used the experimental kelp drag characteristics to derive Reynolds number-dependent normal and tangential drag coefficients. The normal and tangential drag coefficients were determined  through the curve fitting to the experimental data. Afterward, these drag coefficients were utilized for the Saco Bay single-line kelp site described in Fredriksson et al. (2023). Since the drag coefficient is a function of the Reynolds number, all its components (fluid density, velocity, characteristic length, and dynamic viscosity) were calculated cautiously considering the water temperature and salinity of the sites. Comparisons of mooring line maximum, and mean tension values as well as tension spectra and time series were made between the numerical simulation and field data. Furthermore, design and simulated pretension values were also compared.

Ana Silverio, MS - Marine Biology

Assessing the Resistance and Resilience of Recreational Fisheries to Extreme Events  

Photo of a pier over the ocean with green lights reflected on water.

Extreme events, such as hurricanes and winter storms, disrupt marine coastal ecosystems in many ways that often require specific management actions to help populations recover. In addition, as the climate changes there is a predicted increase in the frequency and severity in extreme events. Partnering with the Coastal Fisheries Division at Texas Parks and Wildlife Department (TPWD), we sought to understand how four recreationally popular fish species responded after a major hurricane and a severe winter storm event using long-term fisheries data. Here, we show how fish abundances changed (or not) post-storm and how they compared to one another among eight different bay systems along the Texas coast. Identifying differences in resilience and recovery of fish species to extreme events contributes to our goal of ensuring the health of these important economically and ecologically populations and motivates studies in other parts of the world. 

Matthew Tyler, PhD - Marine Biology

Using Random Forest models to predict kelp habitats at the Isles of Shoals

Photo of diver in water inspecting kelp on sea floor.

Kelp beds in the Gulf of Maine are threatened by rising ocean temperatures and marine heatwaves. Where kelps die off, they are often replaced by turfs of short and bushy red algae. This change in habitat affects which animals are present, and how fish such as cunner hunt their prey, which has repercussions for local food webs. The ability of kelp beds to persist varies across locations and across years, which makes wide-scale monitoring a priority, but SCUBA divers can only survey so many sites. Using a habitat modeling approach allows us to predict seaweed cover over a larger area. GoPro cameras affixed to a metal frame were lowered to the seabed at different sites around the Isles of Shoals, and those sites were assigned to one of four habitat types: bare substrate (mostly sand flats), kelp-dominated habitats, red turf-dominated habitats, or a mixed seaweed habitat. The variables used for modeling were sea surface temperatures calculated from images taken by the Landsat 8 satellite, and derivatives of bathymetry such as direction, curvature, and angle of slope. The model predicts habitat type with 70% accuracy, and suggests that red turfs are not able to replace kelp beds at depths below 16 meters.

Photo of the three GRS 2023 winners.

2023 Presentation Winners


Alyia Caldwell (left)
"Spatiotemporal variation in common tern foraging movements"

Astrid Zapata De Jesus (middle) 
"Effects of microplastics on phytoplankton aggregation"


Chelsea Kimball (right) 
“Wave-Powered Water Pump: Ocean Field Deployment” 

For more information, email

Past Graduate Research Symposium Oral Presentations

Oguz Oruc, PhD, Mechanical Engineering

Motion Control Design for an Uncrewed Underwater Vehicle Based on Nonlinear System Identification

Photo of laptop and remote control, and UUV about to be lowered into water.

Modeling and control of marine robotics have become a conspicuous research topic in the control engineering community in the last decade. Remotely operated underwater vehicles (ROVs) are deployed and used in commercial, military, and scientific areas for many different purposes such as inspection and maintenance of submerged infrastructure, underwater surveillance/maritime, security, and ocean floor mapping most of which cannot be achieved effectively by human operators. However, to be able to operate these vehicles an effective controller must be obtained, and an accurate dynamic mathematical model of the vehicle should be used as a foundation to design the controller. Although conventional modeling approaches are widely used to design a variety of motion controllers, these controllers are not effective against harsh and changing environmental conditions of open water missions, near-surface zones, or changing vehicle configurations, as these changes significantly affect model parameters. To provide an efficient adaptative control rule, real-time updates of model parameters are required, and nonlinear system identification techniques are considered effective approaches to rigorously model underwater vehicle dynamics. In his research, the researcher proposes to identify the dynamics of a small-scale unmanned underwater vehicle with significantly contributing tether dynamics by using a polynomial representation of the NARMAX (Nonlinear Auto Regressive Moving Average with Exogenous Input) model structure with a black-box approach. Based on the experimentally obtained model, various motion controllers are designed and the effectiveness of the controller is shown with the experiments conducted at the facilities of the University of New Hampshire’s Jere A. Chase Laboratory.

Mary Kate Munley, MS, Marine Biology

An Inside Look at Channeled Whelk (Busycotypus canaliculatus) Fishery: Using Underwater Video as a Tool for Investigation into Trap Dynamics, Whelk Feeding Behavior, and Alternative Baits

Photo of student on boat crouching in front of cage.

Channeled whelks (Busycotypus canaliculatus) support an important commercial fishery along the eastern coast of the United States in which whelks are fished with baited traps. The primary bait attractant used is horseshoe crab (Limulus polyphemus), however, there is pressure to conserve horseshoe crabs and reduce their use in the whelk fishery. In a prior study, we evaluated sustainable alternative baits in the laboratory and identified two promising potential alternatives: 1) Green Crab + Clam Bits + Alginate Binder Mix and 2) Green Crab + Clam Bellies + Alginate Binder Mix. In this study, these alternatives, as well as female horseshoe crab, were tested in the waters off Martha’s Vineyard, MA using a Whelk-Trap Video System (WTV) to evaluate channeled whelk behavior, gear interactions, and attraction to alternative baits in the field. A total of 41 traps were deployed and whelk activity was recorded with time-lapse video over a total of 1778 hours during summer-fall 2022. Channeled whelk traps are a highly efficient method for catching whelk for market or for stock assessments as WTV only had a 0.3% escape rate (1 whelk out of 395). Channeled whelks demonstrated nocturnal feeding behavior with 90% of whelks entering the traps during nighttime hours (18:00-6:59 hours) when light intensity was <22 lumen/m2; the majority (65.4%) of whelks entering the trap within the first 12 hours regardless of bait tested. Traps with alternative baits caught 60% fewer whelk compared to traps baited with female horseshoe crab but bait type did not impact the size of whelk caught. Although not as attractive to whelk as horseshoe crab, whelks were attracted to alternative baits indicating the potential for diversifying baits in the fishery; testing other fisheries processing waste streams and chemo attractants warrants future research to alleviate pressure on horseshoe crab fisheries. WTV is a valuable tool for understanding channeled whelk trap dynamics and can be used to understand whelk behavior, the effects of escape vents, and the effectiveness of future alternative baits.

Tamar Nada, PhD, Oceanography

Towards Automated Nautical Chart Compilation

Color illustration showing water with input/output.

Significant amounts of labor-intensive effort and time are needed for compiling and maintaining Electronic Navigation Charts (ENCs). The great amount of data collected with high-resolution systems that are being delivered to the charting divisions along with initiatives within the divisions, often lead to a bottleneck situation. Therefore, nowadays, one of the main objectives in many Hydrographic Offices (HOs) is automating generalization tasks to improve productivity, and speed up the process, in a cost-effective manner. However, regardless of the various relevant research efforts and the advancements in technology, most generalization tasks are still performed manually or semi-manually, where a likelihood of human error is expected. The ideal situation would be a fully automated solution which could minimize the time and effort needed for ENC production and support rapid chart updates. In this research, towards automated chart compilation through scales, an Automated Nautical Generalization (ANG) model is developed in the Esri environment. The ANG model is used to form a comprehensive generalization process that utilizes the generated nautical constraint template, the source data, within the areas of interest, to perform generalization of the selected ENC features for the target scale with no topological violations.

Glenna Dyson, MS, Oceanography

Fine-scale niche modeling growth and disease cover trends of long-term outplanted staghorn corals (Acropora cervicornis) in the lower Florida Keys

Diver measuring coral with a tape measure underwater.

Habitat suitability models have long been utilized within restoration ecology to project areas of range expansion, diversity hotspots, and potential locations for nursery-reared outplant success. In the Florida Keys, multiple species have been targeted for coral restoration, especially Acropora cervicornis due to its importance as a reef building stony coral. Thus far habitat suitability models have utilized coarse spatial data of large areas throughout the Caribbean, resulting in recommended outplant sites that restoration groups have limited capacities to access. Additionally, coral success can vary widely within a limited space, necessitating the understanding of how to project optimal outplant locations within a restoration site. Reported here generalized mixed models project site-specific location of high A. cervicornis growth and healthy coral cover in the long-term, based on fine-scale seafloor characteristics developed from Structure-from-Motion digital elevation models. Convex terrain, rough terrain, marine heat and cold waves projected negative relations to coral growth. Slope, distance from coast, and high wind events projected positively on growth. Percent healthy cover significantly decreased after two years of outplantation. Depth, distance from coast, decreasing terrain roughness, and proximity to the spur-and-groove interface, projected higher percentages of healthy coral cover. Cumulatively, these results emphasize the importance in long-term monitoring and fine-scale surveying when utilizing habitat suitability models to make site recommendations for coral outplanting.

Shelby Perry, MS, Marine Biology

The Effects of Hatchery Stressors on Growth, Aggression, and Cannibalism of Juvenile Lumpfish

Photo of juvenile lumpfish in a blue tank.
Due to the high demand for cleanerfish in salmonid ocean farming operations, increasing lumpfish hatchery production and rearing efficiency are of great importance. Juvenile lumpfish are cannibalistic which is partially controlled though frequent size grading of the fish, however, cannibalism still occurs. We hypothesize that lumpfish cannibalism is linked to a specific ontogenetic period related to fish size and can be exacerbated by various stressors such as stocking density and photoperiod. Two size classes of juvenile lumpfish (5 g and 11 g) were subjected to varying densities (40 g/L, 65 g/L, or 90 g/L) under different photoperiod regimes (ambient, constant low light, or constant bright light) for an 8-week duration in winter 2022. Fish growth, survival, and aggression were measured biweekly, and stocking densities adjusted to baseline levels biweekly by removing any necessary fish. In the ambient light treatment, 5 g fish grew significantly (31.5 %) faster than fish in the low light treatment and 28.5 % faster than fish in the high light treatment. Stocking density did not have a significant effect on overall percent growth of 5 g fish. Neither stocking density nor light significantly affected the overall percent growth of the 11 g fish. A significant interaction between stocking density and light on aggressive behavior in 5 g fish was found. Fish in the low light 40 g/L treatment had significantly less fin nipping than those in the low light 65 g/L and high light 40 g/L treatments. Fin nipping amongst the 11 g fish was not significantly affected by either stocking density or light. A trend towards higher fin nipping in smaller fish was observed (~45 % fin nipping occurrence in 5 g fish vs ~20 % in 11 g fish), indicating that cannibalism may be even greater when fish are < 5 g but decreases as the fish grow. Our results indicate that manipulating lighting and stocking density (up to 90 g/L) can be used to suppress or increase growth rates in small lumpfish, depending on a hatchery’s desired outcome, without resulting in an increase in fish aggression.

Chelsea Kimball, MS, Mechanical Engineering

Wave-Powered Water Pump: Ocean Field Deployment

Grad student holding rope on vessel attached to research buoy in water.

The UNH student designed Wave-Powered Water Pump is a Wave Energy Converter (WEC) upwelling device. By utilizing relative motion of the two main floats, a piston and check valves create pumped flow. This effect has the potential to bring nutrients and colder water to the surface, which enhances the productivity of macroalgae. Improvements were made to the Wave Pump device, in preparation for an ocean field deployment. Sensors were added to measure its performance in a variety of ocean wave conditions. A lidar sensor was added to measure the relative motion of the main floats. A flow meter in a custom-made housing was installed to measure the amount of pumped water. The data and GPS time were and recorded in a solar-powered DAQ. Environmental monitoring sensors were also used during the deployment. These included a Sofar Spotter buoy to monitor wave and weather conditions, two hydrophones, and motion-triggered cameras. The R/V Gulf Challenger deployed the Wave Pump device in March 2023 on a Shoals Marine Laboratory mooring located off Appledore Island, ME. Preliminary data indicates device performance and responsiveness in various wave conditions. Future work includes quantifying performance metrics, validating a numerical model of the device, iterating the design based on the results, and further analysis of the environmental monitoring data.

Jonathan Clark, PhD, NRESS

Genomic architecture of local adaptation in a coastal Song Sparrow subspecies

Image of student holding songbird by the feet in a field.

Interbreeding populations that maintain divergent adaptations provide an opportunity to examine the genetic basis of local adaptation. The song sparrow (Melospiza melodia) is a ubiquitous North American songbird with several subspecies adapted to diverse environments. In eastern North America, there are two song sparrow subspecies, the generalist Eastern Song Sparrow (M. m. melodia) and the Atlantic Song Sparrow (M. m. atlantica), which is adapted to coastal sand dunes and salt marshes. Despite gene flow in their contact zone, these subspecies maintain divergent adaptations to their respective environments. Namely, the bill of the Atlantic Song Sparrow is roughly 30% larger than the Eastern Song Sparrow, allowing for more efficient heat diffusion and water conservation. We used whole-genome sequencing (15X depth) of 60 individuals (inland = 20, coastal contact zone = 18, barrier islands = 22) to discern population structure, characterize highly divergent portions of the genome between these subspecies, and identify the genes associated with coastal adaptation in the Atlantic Song Sparrow. Our results provide insights into the genomic architecture of adaptation with gene flow and the genetic basis of coastal adaptation in songbirds.

Kindrat Beregovyi, PhD, Computer Science

Calculating Rugosity from Structure-from-Motion Models of Complex Habitats

Computer image of ships and 3D modeling.

Structural complexity, the physical geometry of a habitat, including the substrate itself and the biological structure of inhabitant species, is widely known to influence a range of ecological processes. One of the most widely used and supported measures of structural complexity is rugosity. The traditional measurement of rugosity is the chain-and-tape method. Though this method is useful, it is time-consuming, has limited spatial coverage, prone to error and is difficult to reproduce. With the advent of SfM 3D modeling and mapping, digital rugosity measurements have gained traction. Yet, many of the existing techniques for calculating rugosity on SfM models yield only a single rugosity value for a model, while others cannot properly handle highly complex 3D structures, e.g. coral reefs. We present a novel algorithm to compute rugosity measurements for highly complex 3D models at varying scales. An accompanying free application is provided to facilitate use of this algorithm by other ecologists on their own data. Discussion is provided on the inherent limitations of rugosity as metric, and how more-advanced metrics, made possible by the collection of detailed 3D models, may ultimately be more useful for benthic ecologists.

Kelsey Meyer, PhD, Marine Biology

Ask your Local Oyster Grower about Green Crabs

Image of student holding crab trap on boat.

New Hampshire is an up-and-coming state in the oyster aquaculture industry. Recreational oyster harvesting and oyster aquaculture have boomed in NH waters over the last several years. Investigating predation by the invasive green crab is important so that we can gain a better understanding of the impact invasive crabs may have on these ecologically and economically important bivalves. This study ties together multiple disciplines, social science, field biology, and ecogenetics, to understand the green crab: oyster relationship in NH. The aim of this study was to 1) document NH oyster growers’ perspectives on the issue of green crabs and oyster predation and 2) to perform a quantitative survey of green crabs, their abundance, and their diet at oyster aquaculture sites. NH oyster farmers were surveyed to develop a preliminary understanding of their perspectives and needs regarding the increasing green crab population in NH waters. Conducting this type of social science is important to fill knowledge gaps, develop future research, and create and implement solutions for the NH oyster aquaculture industry. A subsequent field study of green crab occurrence, distribution, and feeding was designed with their concerns in mind and implemented over a two-year period in Great Bay. Results indicated that as the green crab population is increasing in the Bay, their distribution is not uniform throughout the estuary. Metagenomic analysis of green crab gut contents indicated that green crabs in Great Bay are eating primarily tunicates and gastropods (e.g., oyster drills), not oysters. These data were shared with the NH Shellfish Farmers’ Initiative. Farmers recognized the potential importance of crabs due to the increase in crab abundance and the gut analysis serves to give the farmers information they need to adjust cultivation practices. In response to the current data, farmers helped to design a separate final study to measure specifically whether green crabs inside oyster trays 1) consume aquacultured oysters or 2) to determine the potential effectiveness of green crabs to provide a service to oyster farmers by consuming predators and biofouling organisms. Future studies should employ similar social science components to enlist the experience and share information with affected stakeholders.

Terence O'Brien, MS, Oceanography

Temporal variability of light penetration in the summertime Gulf of Maine with implications for satellite ocean color observations

Photo of student on boat surrounded by equipment.

Accurate modeling of the depth of light penetration and the depth-resolved absorption and attenuation within the water column is critical for accurate estimates of radiant heat flux and potential primary production, especially important in the context of quantifying biological carbon flux and sea surface temperatures in a changing climate. In this study a moored vertical profiler is used to collect sub-hourly light attenuation data throughout 3 seasons in 2021 and 2022 in order to examine temporal variability associated with solar zenith angle, cloud fraction, mixed layer migration, and changing bio-optical properties. Measurements were made offshore in the Gulf of Maine at high vertical resolution (< 1 m) using a Wirewalker system that includes a PAR (400 - 700 nm) planar irradiance sensor as well as optically-derived Chla and particle backscatter. Focus is on two light extinction metrics, the e-folding depth of blue-green light and the euphotic depth. The former is closely related to the first optical depth associated with the surface water leaving radiances in the blue and green (490 and 550 nm) measured using ocean color satellites, commonly used for estimates of the euphotic depth. Significant mixed layer depth variations of 5-15 m were observed throughout the July-Sept. stratified period, dominant at a semi-diurnal frequency in phase with the M2 internal tide, and found to impact optical depths primarily due to change in the chlorophyll maximum depth location in phase with the tide. The continuous time series also permits a first-order estimate of hourly Chla change above the e-folding depth that would be inferred from water-leaving radiance data, as well as at the 10-12 local time hours typical of satellite observations. Results again show variability that correlates strongly with the tide, with increased variability during spring tide periods. The Gulf of Maine, with high seasonal variability, provides a unique study area in which a variety of optical water types are encountered, making this investigation useful to a range of areas around the globe with implications for ecosystem modeling and remote sensing. This work is part of the Acoustic and Environmental Observing Network in the NW Atlantic (AEON) project.

Katie Kirk, PhD, Oceanography

Observations of Shear Instabilities of Tidal Currents in Hampton Inlet
Simple barotropic linear stability analysis suggests that strong cross-channel shear of tidal currents flowing through a bounded inlet can lead to instabilities in the flow, causing a meandering of the mean along-channel current and potentially the spinoff of large eddies. The resulting variability of the currents and vorticities may affect navigation and the transport of organic and inorganic matter, and cause lateral mixing of momentum across the inlet. To estimate the wavenumbers of shear instabilities within Hampton Inlet, NH, a spatially-lagged array spanning 389 m consisting of seven acoustic Doppler velocimeters and current profilers equipped with pressure sensors were deployed along the ~3 m depth contour for one week during the spring tide in May 2021. Using iterative maximum likelihood estimators, wavenumber-frequency spectra are estimated during 2-4 hour periods with approximately steady currents on both the flood and ebb tide. Dominant wavenumbers (+/- 0.001-0.015 m-1) of the low frequency motions (0.0015-0.01 s-1) are resolved and consistent with motions determined from the linear stability analysis. The instabilities are directed into the inlet on flood tides and out of the inlet on the ebbs, consistent with the expected propagation of unstable modes. The normalized velocity-to-pressure variance ratio, R, at each station shows that the infragravity band is dominated by shear wave motions (R&gt;&gt;1) during both the flood and ebb tide. The lack of breaking wave group modulations within the inlet and the presence of the seaward propagating instabilities on the ebb flow indicate that the presence of the instabilities can be attributed to the shear of the tidal current. Characteristics of the observed instabilities will also be presented in terms of the predicted linear stability analysis for the bounded inlet geometry with a deep center channel (4-10 m, tidally dependent) and shallower lateral side shelves (0-4 m).

Alyssa Stasse, PhD, Marine Biology

Temporal dynamics of eastern oyster larval abundance in GBE, NH
Eastern oyster, Crassostrea virginica, populations have been declining steadily over the past several decades across the North American East coast.  Great Bay Estuary (GBE), located in New Hampshire, is experiencing this loss and restoration efforts have been put into effect. This study characterized abundance in GBE from 2018 to 2020 of two early larval stages of C. virginica, D-hinge and veliger, and settled spat.  The putative effects of month, year, site, and physicochemical factors were examined.  D-hinge larvae and veligers already were present in the water column when sampling began (June), and spat settlement already had occurred, suggesting an earlier than previously thought first spawn of C. virginica in GBE.  D-hinge larval abundances declined significantly from 2018 to 2020, whereas veliger abundances remained steady and increased slightly in 2020 (Figure 1).  Although physicochemical factors are known to play a role in larval abundance, no significant effects other than temperature were noted. Spat settlement was found as early as June (Figure 2), suggesting an earlier than previously thought spawning period of eastern oysters in GBE. The findings are being used to enhance restoration efforts as they suggest that spat brought in to augment current sites of active restoration should be collected and deployed earlier in the season and that recruitment devices should be deployed earlier each year.

Natalie Lord, MS, NREN

A Rising Tide? The role of social networks for women oyster producers in Maine and New Hampshire
"This presentation provides preliminary results from my MS research on the roles and experiences of women in the oyster aquaculture industry of Maine and New Hampshire. It contributes to emerging research applying both gender and social-ecological systems analyses to understand how gender dynamics impact barriers and opportunities for aquaculture producers in the United States. New England is a leader in sustainable aquaculture practices and, in comparison with other parts of the country, it has high numbers of woman-operated leases for shellfish cultivation. Integrating gender analysis in aquaculture development is critical to ensure equal access and opportunity for women to a viable business, a social support system, and the ability to produce food with positive impacts on ecosystem biodiversity, water quality, and a small or neutral carbon footprint. This project aims to (1) share stories about women’s experiences as oyster producers in the aquaculture sector, (2) identify institutional barriers and opportunities for women to work as producers, focusing on analyzing the ways in which social networks influence how women build businesses on the water, and (3) make recommendations for gender integration into aquaculture policy. With a community-based methodology of an industry-wide survey and a Photovoice case study with four women farmers, this research works to create a baseline of information so the industry can make decisions about what steps may be needed to advance justice, opportunities, and access more equitably across genders within the industry. This process requires an intersectional approach that centers equity, diversity and inclusion for all forms of oppression including gender discrimination. My research focuses specifically on gender equity, but my hope is that supporting participation of women aquaculture producers will improve knowledge about pathways for other marginalized groups to enter the industry and foster equal economic opportunities for working on the water and growing local, sustainable seafood.

Patrick O'Byrne, MS, Ocean Engineering

In-Situ Performance and Load Measurements for a Grid Connected Tidal Energy Conversion System
A tidal energy conversion system has been deployed at Memorial Bridge that spans the Piscataqua River between Portsmouth, NH and Kittery, ME, since 2018, originating with the NSF-funded Living Bridge Project. The tidal currents at the deployment location exceed 2.5 m/s during spring ebb tides, which provides an excellent and unique open water flow environment to test tidal energy conversion devices. A recent project conducted in collaboration with the National Renewable Energy Laboratory (NREL) had the objective of making concurrent power performance, thrust load and tidal current resource measurements, while the turbine is in grid-synchronous operation. The existing electrical power production components, control logic and data acquisition systems required significant improvements to prepare the system for these measurements. The focus of this presentation is on the work scopes that were completed that allowed for a significant data acquisition campaign in the Fall of 2021 with 29 days of grid-synchronous turbine operation. Example results from the measurement campaign will be presented.

Brandon O'Brien, PhD, Marine Biology

Biogeography and invasion potential of five invasive seaweeds under projected ocean warming
Introduced seaweeds can have severe negative impacts on their introduced ecosystems, often through the alteration of physical habitat space. One question surrounding every invasive species is whether or not it has reached its geographic limit, or if it will continue to spread. In this study we investigate the invasion potential of five widely introduced seaweeds: Caulerpa taxifolia, Codium fragile subsp. fragile, Dasysiphonia japonica, Sargassum muticum, and Undaria pinnatifida. Species distribution models were used to predict the potential geographic distribution of each species under present-day and future climate warming scenarios. The most important driving environmental variables for each species were also investigated. Under current conditions, minimum sea surface temperature had the highest percent contribution in the models of all species. Under current conditions, all five species were found to have significant potential to invade new territory. Under future conditions, evidence of potential range contraction and poleward expansion were apparent in several species. The projected models showed C. taxifolia to have the greatest loss in potential highly suitable habitat, and U. pinnatifida to have the greatest gain. These results show that there will be species-specific responses to ocean warming, making it difficult to make broad statements about future threats by invasive species.

Sydney Adams, MS, Civil and Environmental Engineering

Understanding the Fate and Transport of Per- and Polyfluoroalkyl Substances (PFAS) in Wastewater Systems

This thesis explores the story of per- and polyfluoroalkyl substances (PFAS) in New England wastewater systems. PFAS compounds, known for their environmental persistence, toxic nature, and heavy integration into our daily lives, has recently become an infamous topic in environmental engineering due to the discovery of contaminated agricultural lands, water resources, and food systems. In response to these daunting discoveries, regulators have begun looking to reduce point source pollution of PFAS, including that of wastewater systems and facilities. As conduits of PFAS, wastewater systems funnel PFAS from industrial, commercial, and residential sources and emit them into the environment via aqueous effluent and solid sludges. Considering potential legislative pressure, there is increasing tension to understand PFAS trends and behaviors within wastewater systems including identifying considerable source types in sewer sheds, fractionation of PFAS into solids, transformations of precursor compounds within secondary biological treatment processes, and effect of sludge processing on PFAS transformations and composition. We look to explore these behaviors using a series of PFAS concentration data from wastewater systems across New Hampshire and Vermont in a variety of statistical analyses looking at concentration, composition, and mass flow comparisons. Further work from this analysis, looks to develop a passive membrane sampler to understand PFAS transformations within wastewater systems to better understand transformation pathways encouraged in certain wastewater settings, knowledge vital to the development for PFAS mitigation and regulation strategies.

Kaitlin Van Volkom, PHD, Marine Biology

Rise of the slipper limpet, Crepidula fornicata: Effects of an increasing prey population on crustacean predators

Benthic environments in the Gulf of Maine are rapidly changing as a result of climate change, species introductions and range expansions. The native slipper limpet, Crepidula fornicata is one species that has experienced a rapid population expansion in the past decades, while important prey species like blue mussels have declined. Slipper limpets are a benthic gastropod species that form dense beds and are known prey items for locally important crustacean species, such as lobsters and cancer crabs. Population surveys were conducted across coastal New England in the summer of 2021 in order to measure population densities of limpets in benthic habitats. Prey preference and nutrition studies were conducted with both mussels and limpets. We show that limpet populations in New England are substantially higher than predicted. Preliminary prey choice studies revealed that crabs consumed more mussels than slipper limpets. Crabs preferred small and medium size mussels over large mussels, and medium and large sized limpets over small limpets. Smaller mussels likely have a short handling time, and medium and large limpets contain more meat than small limpets. As the preferred prey of crabs decline, it is vital to understand how commercial crab populations will be affected by shifting prey diets.

Sydney Birch, PHD, Molecular and Evolutionary Systems Biology

The actinula larva of Ectopleura crocea (Hydrozoa) utilizes multisensory integration (MSI) in the larval settlement decision
It is often advantageous for organisms to integrate sensory information from more than one modality to make critical behavioral decisions. This can be accomplished by multisensory integration (MSI) which is a process that combines information from two or more sensory modalities and results in a different response from the individual sensory stimuli. Larvae of sessile marine invertebrates use environmental sensory stimuli to irreversibly settle and metamorphose. It can be expected that with such an important survival decision that larvae leverage information from multiple sensory modalities. However, MSI has yet to be deeply investigated in marine larvae that lack complex nervous systems and brains. Here, we examined the settlement response of the actinula larva of the hydrozoan Ectopleura crocea, which possess a diffuse nerve net, and found that actinulae utilize MSI during larval settlement. We performed a factorial larval settlement study that revealed larvae are sensitive to photo- chemo- and mechanosensory cues and settle in complex ways to different combinations of cues, indicating MSI. In addition, we conducted a developmental transcriptome study which highlighted the peak expression of a comprehensive set of candidate sensory genes at the developmental stage when larvae are competent to settle. Finally, RNA fluorescent in situ hybridization studies of candidate sensory genes showed that many of the sensory genes of interest are expressed in the same sensory neuron, suggesting that the process of MSI in E. crocea takes place within a sensory neuron and not between specialized neurons or neural regions as in other animals. Our results indicate that MSI plays an important role in mediating the larval settlement decision in E. crocea and suggests that this process may be accomplished by integrating different lines of sensory information within a polymodal sensory neuron.

Aditi Tripathy, MS, Marine Acoustics

Weathering the storm: impacts of hurricane-induced noise on the probability of detecting cetaceans

Hurricanes Dorian (Category 5; 2019), Florence (Category 4; 2018), and Humberto (Category 3; 2019) impacted the underwater soundscape as observed at the Atlantic Deepwater Ecosystem Observatory Network (ADEON) locations in the US Mid- and South Atlantic Outer Continental Shelf. Passive acoustic data obtained from bottom-mounted hydrophones at the ADEON locations were examined to assess changes in ambient sound before, during, and after hurricane presence. Ambient sound level increased up to 25 dB in the 0.1-7 kHz band which could impact the detectability of cetaceans vocalizing at those frequencies. The probability of detection (Pd) of fin whales, minke whales, and pilot whales was estimated at each ADEON location using measured ambient sound levels, modelled propagation loss, and pre-defined detection parameters. Pd changed considerably during hurricane presence with site-specific impacts for each of the cetaceans, which may affect estimates of their abundance from passive acoustic recordings. [Study concept, oversight, and funding were provided by ONR Award N00014-16-1-2594 and BOEM under contract Number M16PC00003, in partnership with ONR and NOAA. Funding for ship time was provided under separate contracts by ONR, Code 32.]

Sarah Benson, Oceanography

Warming temperatures increase microbial consumption of marine organic matter

Marine microbes are vital to oceanic ecosystems and influence the global climate through their paramount role in Earth's biogeochemical cycles. With this intricate role in ecosystems, it is important to understand the effect of increasing ocean temperatures on the cycling of organic matter (OM). We experimentally investigated the temperature sensitivity of microbial consumption of marine particulate OM focused in the rapidly warming Gulf of Maine during the 2019 and 2020 Fall bloom. The overall rate and quantity of microbial OM (C, N, and P pools) consumption at in situ versus elevated temperatures were quantified within bottle incubations over the course of two weeks. The results indicate that OM incubated at warmer temperatures (+5 - 6°C) was significantly different and consumed at a faster rate with an overall larger quantity consumed compared to cooler temperatures (12 -14°C). Additionally, nitrate that was initially produced from the consumption of particulate organic nitrogen (PON), was readily consumed at later time points at both temperatures, possibly related to the carbon-rich, nitrogen-poor quality of the in situ OM. Overall, more nitrogen-rich OM was primarily consumed at cooler temperatures, leaving behind carbon-rich OM. Whereas at warmer temperatures, carbon-rich OM was primarily consumed presumably due to it being a bioavailable energy source to fuel elevated metabolic rates. The temperature coefficient (Q10) ranges from 2.66 - 3.42 in 2019 versus 0.94 - 1.21 in 2020, dependent on the OM elemental pool, suggesting temperature plays an important role in OM consumption, but is not the only factor contributing to faster rates and overall quantities.

Jang-Guen Choi, Oceanography

Expanded NPZD model considering non-Redfield dynamics and parameter sensitivity experiments

Various marine ecosystem models have been developed to simulate large scale pelagic ecosystems, but collectively do not consider benthic processes and non-Redfield dynamics. As a result, the open ocean models cannot properly resolve the coastal ecosystem, and thus tend to underestimate phytoplankton biomass off the shallow coasts often rendering unrealistic oligotrophic water masses. In this work, we expand the traditional Nutrient-Phytoplankton-Zooplankton-Detritus (NPZD) model to consider non-Redfield dynamics including nitrogen fixation and denitrification, and show that the expanded model has much more plausibility in nature than traditional NPZD models. Our expanded model is designed to minimize complexity, and allows for steady-state solutions to be analytically determined. Solutions show that internal dynamics of the coastal ecosystem eliminate the chronic miss-representation of oligotrophic water mass predicted by the pelagic model, and are qualitatively consistent with observations off the coast of Korea. Parameter sensitivity experiments are conducted to estimate uncertainty of the model coefficients and find best-fit coefficients. We expect that the expanded model can be used to improve predictions of harmful algal blooms in coastal marine ecosystems.

Michael Doherty, Biological Sciences: Marine Biology

Parasitic sea lice populations in an experimental salmonid aquaculture system in NH waters and using lumpfish as a possible solution

Sea lice are copepodid ectoparasites that infect fish, and cost salmonid farmers millions of dollars each year in damaged product and mitigation efforts. Conventional treatments can unintentionally impact the ambient environment and lead to the lice developing resistance to the treatments. In recent years, lumpfish (Cyclopterus lumpus) have been utilized successfully to naturally clean sea lice from infected salmonids. In NH coastal waters, NH Sea Grant and UNH operate an experimental steelhead trout farm, AquaFort. To understand seasonal occurrence of lice populations at AquaFort and when lumpfish use would be most effective, trout were subsampled weekly for sea lice during farm use throughout 2019-2021. Lice abundance, species present, sex ratio, life stage, and occurrence of gravid females were determined. To understand how lumpfish could mitigate sea lice infestations, smaller (785 L) experimental cages were stocked with different treatments of steelhead trout, lumpfish, and lumpfish hide designs. Water temperature, fish mortality, lice loads, and lumpfish stomach contents were analyzed during two 5-week trials to examine lumpfish impacts on sea lice loads. In both trials, there were significantly different mean lice loads on trout between the hide designs, though no evidence of sea lice was observed in lumpfish stomach content analysis. One trial displayed significantly different mean lice loads between lumpfish and trout. These results suggest that lumpfish size, trout strain, hide design, and water temperature act as variables to consider for effective sea lice control. These foundational studies contribute towards developing best practices of lumpfish use for sea lice mitigation, leading towards the goal of increasing the sustainability and production of steelhead trout aquaculture in NH.

Kerry Dykens, Oceanography

Essential workers of the sea: The effect of changing environmental conditions on the critical functions of marine microbes

Microbially-mediated biogeochemical cycles in the ocean are dependent upon environmental conditions, however, the extent to which environmental factors drive patterns in heterotrophic activities is less understood. Microorganisms are essential to the cycling of organic matter and inorganic nutrients through their enzymatic depolymerization of high molecular weight compounds. Because microorganisms adapt relatively quickly to their environment, their enzymatic activities can reflect biological responses to changing environmental conditions, such as those predicted as a result of climate change. The response of microbial enzymatic activities to environmental variability was studied at three coastal sites in the Gulf of Maine (GOM), i.e., a highly productive and rapidly warming water body of the Atlantic Ocean on the east coast of the US. Samples were taken between March 2018 and January 2020 covering a range of water temperatures from 1.7°C to 21°C.  Fluorogenic substrate proxies were used to assay β-glucosidase (BG), leucine aminopeptidase (LAP), and alkaline phosphatase (AP), catalyzing hydrolysis of carbohydrates, peptides, and phosphorous compounds, respectively. Despite sampling a relatively narrow geographical region, the enzymatic activities displayed distinct site-specific patterns. Potential enzyme activities were correlated with sea surface temperature, salinity, chlorophyll-a (chl-a), and bacterial cell abundance to evaluate the effects of environmental parameters on rates and patterns of the selected enzymes. Temperature had a moderate effect on LAP activities at one of the sites. The other two enzyme activities showed weak correlations with temperature, suggesting that environmental factors other than water temperature determined seasonal patterns of enzyme activities throughout the investigation period. Moderately strong relationships were found between chl-a and AP activities at two of the three sites, indicating relationships between phytoplankton growth and remineralization of inorganic phosphorous from organic matter. Salinity had a medium to large effect on the activities of BG and LAP, while changes in all three enzyme activities were decoupled from variations in bacterial cell abundance. Our results indicate that water temperature, despite its substantial range, was not a main driver of enzymatic activities throughout the investigation period.

Nathan Hermann, Biological Sciences: Marine Biology

Arctic seasonality contributes to variable resident sculpin feeding and movement behaviors

The Arctic is characterized by seasonal cycles of complete darkness and complete daylight. These dramatic changes in light lead to strong pulses of productivity when the sea ice melts in summ that in turn attract marine migrants from hundreds of kilometers away. It is less apparent if resident species similarly exploit this productive period given their limited mobility. Sculpin (family Cottidae) are resident fish of temperate and Arctic waters known to feed on local zooplankton and presumed to move little, using a lie-and-wait foraging strategy. To determine the feeding intensity and diet composition of sculpin during the annual productivity pulse, we collected sculpin (N=158) during the summer ice-free periods of 2017-2019. Consumption relative to fish body mass was compared within (late-July - early-September) and across summers. The multivariate prey community was compared across individual sculpin and time periods to observe presumed flexibility or selectivity in composition. To monitor and compare space use between ice-free and ice-covered seasons, individual sculpin were tracked using acoustic telemetry. Home range size was calculated in each season based on detected positions for each individual. Relative consumption was high, ranging from 0-12.1% (median 3.37), and stable both within (p=0.166) and across (p=0.602) years. Despite consistent feeding intensity, diet composition was highly variable, both increasing in breadth within years and having different major prey items each year. This period of intense, but flexible, feeding corresponded to increased home range size compared to ice-covered periods (p=0.001). In addition to larger home range size, sculpin showed a greater use of the outer limits of their home range indicating more exploratory movement during the ice-free summers (p=0.001). Collectively, our results demonstrate that sculpin exhibit markedly seasonal behaviors that enable resource exploitation during the ice-free pulse. Though resident populations are not spatially disconnected from the seasonal resources they exploit and sensitive to pulse timing as migrants are, sculpin feeding shows they may still be sensitive to dampened pulse magnitude or increased competition. As the Arctic experiences rapid climate change, it is important to consider a wide assemblage of species and niches which may be threatened in unique ways and to different extents.

Grant McKown, Biological Sciences: Marine Biology

Short-term Restoration Performance of Living Shorelines in the Great Bay Estuary, New Hampshire

Salt marsh living shorelines (LSs) have been shown to improve the resiliency of coastal shorelines and restore salt marsh ecosystems. A common type of LS is the restoration of fringe salt marsh habitat with the inclusion of a riprap sill at the low marsh edge. Recent studies have shown quick recovery times for vegetation and infauna, however no published studies have addressed this question in northern New England LSs. We monitored the short-term restoration trajectories of the first three LSs in the Great Bay Estuary, New Hampshire by sampling vegetation, nekton, and pore water chemistry in a BACI design. The Restoration Performance Index (RPI) quantified the restoration performance of the LSs by converting abiotic and biotic metrics into an relative score from 0 - 1. LSs recovered quickly to a RPI score of 0.5 within three years post-restoration and the recovery followed a logistic restoration trajectory, plateauing at 0.52 + 0.04. The unweighted vegetation RPI score followed a similar logistic trajectory with an upper asymptote of 0.67 + 0.06. High marsh species richness increased over project age to 4.3 + 0.8 species per plot. Halophyte cover did not follow a restoration trajectory over time. Mummichog abundance and size were statistically similar between LSs and the nearby reference sites. Soil reduction-oxidation potential became slightly anaerobic after three years (-41.7 + 10.9 mV). The abiotic and biotic factors recovered at different timeframes, with vegetation and nekton recovering to near reference conditions within four years. Pore water chemistry did not have a substantial RPI score throughout the study, suggesting biogeochemical processes and soil characteristics may require longer timeframes to recover. LS projects experienced various stressors which hindered the recovery of ecosystem structure and functions such as erosion, geese herbivory, and high plant mortality at the seaward edge. The LSs in the Great Bay Estuary provide meaningful coastal habitat and shoreline resilience yet will require maintenance to ensure restoration goals are continually met.
Nathan Spada, Biological Sciences: Marine Biology

Nutritional and density dependent effects on the growth of juvenile cultured lumpfish

Lumpfish are of interest to the aquaculture industry because of their usefulness as biological controls for sea lice infestations in salmonid ocean farms. Despite millions of lumpfish produced each year for this purpose, hatchery information is still needed for improving lumpfish rearing protocols, including nutritional needs of and stocking density conditions for juvenile fish. During the Summer of 2020, two experiments were conducted at the Coastal Marine Laboratory to determine the ideal nutritional parameters and stocking density for juvenile lumpfish. Diets with varying protein/lipid compositions were tested, including six experimental diets (50/15, 55/10, 50/20, 55/20, 55/15, 50/10), one commercially available lumpfish diet (Skretting Europa, 55/15), and one trout (salmonid) diet (BioTrout, 47/24), a food source that lumpfish would have access to in a trout ocean farm. Fish (initial mean size = 9 g) were stocked into 10 L flow through tanks at 13 g/L, and survival, growth, and aggressive behaviors were monitored for 10 weeks. In a separate study, the effects of different stocking densities (40, 60, 70, and 90 g/L) on growth, survival, and aggression of lumpfish (initial mean size = 13 g) were evaluated over 8 weeks. Mortality and fish aggression were not limiting factors in either experiment. Fish fed experimental diets with 55% protein compositions had the greatest growth, even surpassing growth of fish fed the commercially available lumpfish feed (p= 0.0001). Not surprisingly, lumpfish reared under lower densities had faster growth than fish reared in higher densities (p= 0.0001), however, given that juvenile lumpfish are cannibalistic, the lack of increased aggressive behaviors at higher densities was unexpected. These findings indicate that juvenile lumpfish growth is highest when provided high (55%) protein feeds and low (40g/L) rearing densities. However, lumpfish outgrow their usefulness as cleanerfish in the net pens, so being able to increase or suppress fish growth may prove to be a useful tool for grow out facilities.

Alexandra Padilla, Ocean Engineering

Acoustic monitoring and tracking of natural hydrocarbons gas bubbles over the course of a year

Gas release from natural hydrocarbon seeps (e.g., bubbles of methane or other gases) is spatially distributed across the ocean seafloor and has been studied for decades. The flux of natural hydrocarbons from the seafloor has been observed to vary over a range of timescales and has been linked to external physical processes, such as atmospheric pressure, currents, and tides. In September 2019, a Simrad ES200 split-beam echosounder was mounted to a decommissioned oil platform, known as Platform Holly, and has been collecting high-resolution temporal acoustic data since its deployment. Platform Holly is located within the Coal Oil Point (COP) seep field, one of the world's most prolific natural hydrocarbon seep sites. Natural hydrocarbons have been actively seeping from the COP seafloor for several decades and previous research highlights both spatial and temporal variability within the seep field. Our high-resolution, echosounder acoustic measurements of seepage activity in the vicinity of the oil platform yield a long-term time series that provides insight on the spatial and temporal variability of seepage activity in the region. This time series data allows us to make inferences about how external physical processes influence seep flux.

John Taylor, Oceanography

Fuel from Withing: Can resuspended organic phosphorus fuel harmful cyanobacteria blooms in Lake Erie?

Lake Erie, the shallowest of the Laurentian Great Lakes, has been historically plagued with blooms of potentially toxic cyanobacteria despite efforts to reduce external nutrient input. The Great Lakes Water Quality Agreement signed by Canada and the United States of America in the 1970’s sought to decrease the amount of soluble reactive phosphorus (SrP) entering the lakes through rivers and runoff. In the mid 1990’s blooms of the potentially toxic cyanobacteria Microcystis spp. began to reappear in Lake Erie despite the diminished amount of SrP entering the lake, specifically in the western basin. Due to the shallow nature of the basin (average depth 10 m), events such as summer storms have historically been strong enough to resuspend lake sediment, potentially releasing phosphorus sorbed onto organic and inorganic particles (>0.46 m), termed particulate organic phosphorus (POP) and particulate inorganic phosphorus (PIP), respectively. Microcystis, along with all other cyanobacteria, possess phosphatase enzymes that allow the bacterium to effectively cleave the phosphate group off of organic particles and incorporate it into the cell. We hypothesize that wind-driven sediment resuspension events in the western basin of Lake Erie release POP that potentially fuels summertime Microcysits blooms. We first investigated the amount of P released during resuspension events by exposing sediment cores taken from two sites in the western basin to increasing amounts of shear stress. We quantified the amount of SrP, POP, and PIP released from the sediment cores into the overlaying water. In lab experiments, we exposed cultures of Microcystis isolated from the western basin to varying levels of SrP, POP, and PIP and observed growth rates. The hydrolysis rate of the phosphatase enzyme was studied to determine the usage of the POP pool. These experiments allow us to effectively show if sediment resuspension events in Lake Erie release POP, and if Microcystis can use POP to grow.

Lars Hammer, Biological Sciences

Movements and feeding of Arctic char relative to summer ice-off in an Arctic embayment
Arctic waters are warming faster than anywhere else on the planet. Increased temperatures are expected to affect the seasonal timing of ice-off, an event that provides productivity booms for consumers. Arctic species are adapted to strong seasonal variations in productivity, but exploiting high productivity events may become more difficult if sea ice phenology changes. The Arctic char (Salvelinus alpinus) is a fish of particular concern, providing sustenance and income to Arctic inhabitants through subsistence fisheries. Although char are known to make seasonal migrations to marine waters to feed, their specific timing in relation to ice-off and the subsequent productivity pulse is unknown. Further, the quantity and quality of food consumed during this period will dictate the importance of the ice-off transition for char. To investigate the movement and trophic ecology of Arctic char, 110 individuals were tagged with acoustic transmitters in 2017 (n=58) and 2018 (n=52) within Tremblay Sound, Nunavut, Canada, with an additional 54 char dissected for stomach content in 2018 (n=23) and 2019 (n=31). Thirty-five acoustic telemetry receivers monitored char movements and recorded 625,483 detections from July 2017 until August 2019. Migration timing was closely linked to the timing of ice-off, with individuals arriving right before ice-off and leaving after a month of complete ice-off. Char that summered within Tremblay Sound exited in two directions: toward the river to the south of Tremblay Sound, and toward the marine environment. Char returning to the Sound from the marine environment were larger, maintained larger homeranges, and entered the region later than those entering from the river within the Sound. Collectively, these results might indicate that several char populations exploit the Sound’s productivity. We hypothesize that the use of Tremblay Sound is linked to food availability, particularly of the amphipod Onisimus litoralis, which was found in 69.6% of sampled stomachs after ice-off. Furthermore, char are eating at high rates, with up to 4.6% of their total bodyweight occupied by stomach content. Thus, Arctic char movements and feeding appear dependent upon the ice-off transition with potential behavioral and growth affects if climate change impacts this species’ ability to exploit the seasonal phenomenon.

Zachary Davonski, Ocean Engineering

Evaluating the performance of a multi-tile macroalgae cultivation structure using physical modeling
Macroalgae cultivation structures must be large scale and structurally robust in order to prove successful in an offshore environment. A multi-tile system consisting of kelp growing lines and a structural grid was designed as part of an ARPA-E funded study, and initial computational modeling of this Phase I design has indicated that it is capable of withstanding storm conditions. Phase II of the project focusses on a field study, with the first step being the fabrication of a physical scale model to be deployed in the UNH wave tank. The physical model is a 3x3 tile array, scaled by Froude number to a 1:180 length scale. Deployment in the UNH wave tank allowed for evaluation of the design’s performance during wave and current conditions. The model was subjected to waves and simulated currents in order to investigate its response to dynamic loading conditions, as well any anomalous behavior such as shock loading or component interaction. The motion of the system during various loading scenarios and orientations was captured with cameras and analyzed via a tracking software. The motion data was then used to identify relationships and trends in the system’s response. A finite-element analysis companion study of the physical model was also executed in order to validate the results of the motion data, thus providing a better understanding of how the full-scale system might behave in an offshore environment.

Joshua Humberston, Oceanography

Subtidal Contributions to hydro- and morpho-dynamics at a wave dominated inlet system
Observations of currents and water pressure obtained at 7 locations within Oregon Inlet, NC, over a 40-day period in the spring of 2019 showed subtidal water level oscillations on the sound side of the inlet with magnitudes often exceeding typical tidal ranges. These oscillations, which are correlated with regional wind patterns, induce cross-shore gradients in sea surface slope from the back bay to the ocean that are strongly coupled to inlet current modulations at subtidal frequencies. Owing to their longer temporal scale, the sub-tidal gradients often combine with typical tidal lows to accelerate one phase while retarding or entirely reversing the other. Concurrent observations of bedform migration on the ebb-tidal delta, obtained with x-band radar, suggest these current modifications at sub-tidal frequencies may be important to sediment transport patterns in the inlet and on the ebb-tidal delta. The role of subtidal oscillations on large scale morphologic evolution is further examined through an idealized numerical model that couples hydrodynamics, waves, and sediment transport through the Delft3D modelling suite implemented at Oregon Inlet over observed bathymetry. The nature of the morphologic development of the inlet is discussed in terms of the presence or absence of subtidal oscillations.

Kristopher Wojtuski, Marine Biology

Population Genetic Structure and Mixed Stock Analysis of Striped Bass for Improved Fisheries Management
Striped Bass (Morone saxtilis) is an anadromous teleost with a native range spanning the entire Atlantic coast from the Canadian Maritime Provinces to the St. John’s River in Florida and into the Gulf of Mexico. Substantial spawning populations historically occurred throughout the Atlantic coast but are now limited to four primary river systems, including the Hudson River (New York), Delaware River (Delaware), Roanoke River (North Carolina), and tributaries of the Chesapeake Bay, with many small spawning populations spread throughout the range. While all individuals across the rang spawn annually in fresh to brackish water between the months of April and June, populations north of Cape Hatteras undertake an annual feeding migration to coastal waters as far north as the Canadian Maritimes. These migrating individuals form mixed stocks, or aggregates of fish consisting of individuals from multiple origins, and these stocks support the most popular recreational fishery in the United States. The proportion that each spawning population contributes to the mixed stocks is not known and therefore makes it difficult to manage the species effectively. While considerable research has been recently conducted on the genetic population structure of the non-migratory populations in the southern range, studies identifying the genetic population structure in the migratory range have not occurred since the 1980’s-1990’s. These studies were also conducted prior to the development of high resolution genetic markers and were unable to definitively resolve the genetic population structure within the migratory range of striped bass. The objectives of this study are: 1) to use single nucleotide polymorphism’s (SNP’s) to identify the genetic population structure among the spawning populations of migratory striped bass, and 2) identify the stock composition in 4 areas in the Northeast: New York, Massachusetts, Rhode Island, New Hampshire and Maine. In order to address objective 1 DNA samples from different spawning populations throughout the migratory range were obtained and used to prepare Restriction-site associated DNA (RAD) libraries. The bioinformatics pipeline STACKS was used to call individual genotypes and the population genetics software program STRUCTURE was used to identify the population genetic structure of the spawning populations.

Will Lush, Earth Sciences

In the coastal ocean, species range boundaries tend to cluster in specific alongshore locations. We used estimates of larval dispersal from a global current model coupled with a simple population model to predict where these clusters are likely to arise due to current-driven larval transport. The locations of the predicted boundary clusters are correlated to observed locations of biogeographic boundaries in the coastal ocean, suggesting that currents play an important role in setting the location of biogeographic boundaries in many locations throughout the coastal ocean. Understanding how currents spatially structure species range boundaries is essential to predicting how species ranges will shift in response to a changing climate and for setting conservation and management goals to respond to those changes.

To predict the locations of species range boundary clusters, we tracked simulated larval particles within 1/12° global velocity fields obtained from the operational Mercator global ocean analysis and forecast system (PSY4V3R1, distributed by the E.U. Copernicus Marine Environmental Monitoring Service) and used the trajectories of these particles to generate estimates of current-driven larval dispersal in the global coastal ocean. We used connectivity matrices from these dispersal estimates in a simple two-species population model which was used to find the location of range boundaries.

Erin Heffron, Earth Sciences/Ocean Mapping

The Distribution of an Acoustic Scattering Layer near Petermann Glacier, Northwest Greenland and its Relationship to Regional Oceanography
Mass loss from the Greenland ice sheet has increased rapidly in the last two decades and has contributed significantly to observed sea level rise. The most pronounced change is occurring where ice sheets are grounded below sea level, due to enhanced interaction with warming ocean waters. However, our ability to predict future sea level rise is hampered by our limited knowledge of these glacial systems, including the regional water mass distribution and circulation responsible for that enhanced ocean-ice interaction. The Petermann Expedition of August 2015 encompassed a broad range of data collection in an effort to characterize the Petermann Glacier system, a marine-terminating glacier with a floating ice tongue that has undergone dramatic changes in the last decade. During the expedition, sonars were used to map the water column, generating a continuous dataset over 30 days. This mapping revealed extensive acoustic scattering layers, so called because the components of the layer – typically zooplankton – cause the acoustic energy to scatter much as it does when it encounters the seabed. The layer was observed to change depth in a spatially consistent manner and corresponded to our general, but limited understanding of the complex circulation pattern in the study area. Shipboard insolation data and satellite-derived light attenuation data were used to rule out response to light as the primary reason for changes in the scattering layer depth. Comparison to salinity and temperature measurements were used to demonstrate a pattern in the scattering layer depth distribution related to circulation, confirming that the continuous record provided by acoustics can supplement point observations of temperature and salinity to provide a more complete picture of regional oceanography and the glacial system as a whole.

Hilary Kates Varghese, Earth Science/Oceanography

The Contribution of 12 kHz Multibeam Sonar to a Southern California Marine Soundscape
An ocean mapping survey was conducted over the Southern California Antisubmarine Warfare Range hydrophone range to characterize the radiation pattern of the R/V Sally Ride's EM 122 (12 kHz) Kongsberg multibeam echosounder.  Spanning a 2000 square kilometer area, the 89-hydrophones in the range, combined with the mapping survey, provided the opportunity to study the contribution of this anthropogenic noise to the marine soundscape.  The soundscape was characterized and compared at select hydrophones on the range before and during the multibeam survey.  One second averages of the sound level were calculated over the data collection period. Sound level percentiles (P1, P10, P50, P90 and P99) were calculated for the full spectrum (1 Hz- 48 kHz) and select frequency bands, and spectral probability density plots were generated for each time period.  Frequency correlation matrices were produced for each time period and compared using difference matrices to identify changes in the soundscape.  The results are placed in the context of the auditory scene of Cuvier's beaked whales resident on the range by applying a mid-frequency marine mammal weighting function. [Work supported by NOAA, ONR, and Scripps Institute of Oceanography].

Brandon Maingot, Ocean Engineering/Ocean Mapping

High Frequency Motion Residuals: Identification and Estimation
Advances in multibeam sonar mapping and data visualization have increasingly brought to light the subtle integration errors remaining in bathymetric datasets. Traditional field calibration procedures, the patch test, just account for static orientation bias and sonar to position latency. However, this ignores the generally more subtle integration problems that generate time varying depth errors.
Such dynamic integration errors are the result of an unknown offset in one or more of orientation, space, sound speed or time between the sonar and ancillary sensors. Such errors are systematic, and thus should be predictable, based on their relationship between the input data and integrated output. A first attempt at addressing this problem utilized correlations between motion and ping-averaged residuals [1]. The known limitations of that approach, however, included only being able to estimate the dominant signal, imperfectly accounting for irregular sounding distribution and it only working in shallow water.

This presentation discusses a new and improved means of utilizing the dynamics of the integration error signatures which can address multiple issues simultaneously, better account for along-track sounding distribution, and is not restricted to the shallow water geometry. The motion-driven signatures of multiple integration errors may be simultaneously identified through individually considering each sounding’s input-error relationship from extended sections of a single swath. Such an approach provides a means of underway system optimization using nothing more than the bathymetry of typical seafloors acquired during transit. Successful estimation, however, imposes conditions of significant vessel motion, and smooth, gently rolling bathymetry. Initial results of the new algorithm are presented using data generated from a simulator (with known inputs and integration errors) to test the efficacy of the method.

Tyler Menz, Oceanography

Impacts of Temperature and Salinity on Pteropod Abundance and Distribution off the East Coast in the Atlantic Ocean
Pteropods are pelagic, free-swimming sea snails that have a thin aragonite shell that makes them fairly susceptible to the changing ocean chemistry that is associated with ocean acidification (OA). Pteropods are an important part of the ecosystems they are found in as they are a part of the diet of species at multiple trophic levels and help to facilitate the movement of carbon throughout the water column. Previous studies have shown that pteropods are sensitive to OA conditions as they have shown tendencies for shell dissolution, increased shell opacity, and decreased sinking speeds in more acidic conditions. Changes in other environmental conditions associated with OA, such as rising temperature and salinity, may also impact pteropods. Increased understanding about how the distribution of pteropods has changed as temperature and salinity conditions change can provide insight about how sensitive pteropods may be to these variables. The ECOMON dataset from NOAA Northwest Fisheries Department was used to determine if and how pteropod distribution has changed in the Atlantic Ocean off the east coast of the United States. Statistical analyses performed on the dataset determined there is a relationship between temperature, salinity, pteropod abundance, and their location over time. Ongoing research is further exploring the relationship between pteropod abundance and these environmental conditions.  Understanding how pteropod populations respond to these changing variables is important in further establishing them as bioindicators for OA.

Brandon O'Brien, Marine Biology

Understanding the spread of two invasive seaweeds using digital herbarium records and distribution modeling techniques

Invasive seaweeds are a potent threat to biodiversity in coastal ecosystems worldwide. Only a subset of all introduced seaweeds have made the leap from being locally problematic to global invaders. Here, we explore the use of species distribution models for analyzing the regional-scale distribution of invasive macroalgae. In particular, we attempted to identify locations that may be vulnerable to the introduction of certain highly successful invaders. Models were built for two species: Undaria pinnatifida and Dasysiphonia japonica. Both species are native to temperate Asia, but have become established in disparate regions of the world. Accuracy of the constructed models was assessed by comparing predicted highly suitable habitat to known occurrence records. They were then used to identify areas that may be vulnerable to introduction by either species in the future: U. pinnatifida is already established in a number of areas worldwide, but has yet to reach the Gulf of Maine. Dasysiphonia japonica is relatively recent to the Gulf of Maine, and is not as globally widespread, but may have the potential to spread beyond its current extent.

Jesse Ross, Civil and Environmental Engineering

Potential Role of Marine Oil Snow in the Fate of Spilled Oil in Cook Inlet, Alaska
The objective of the research is to characterize the potential role of marine snow and suspended minerals in the fate of spilled oil in Cook Inlet, Alaska. While extensive research has been conducted on minerals aggregating with spilled oil, larger organic aggregates, such as marine snow, have only recently been studied as a transport mechanism. This knowledge gap in understanding the fate of oil was highlighted following the Deepwater Horizon (DWH) blowout in the Gulf of Mexico (2010) when a significant percentage of the spilled oil was observed sinking to the seafloor as a result of association with marine snow. Research following the DWH blowout suggests both marine snow and mineral sediment are significant pathways that must be considered during an oil spill response. The U.S. Geological Survey and others have noted that an understanding of baseline marine snow conditions in areas of petroleum exploration and extraction is urgently needed. In the summer of 2018 and in January 2019, sinking particles were collected with a surface-tethered sediment trap in eastern Cook Inlet. The summer particle mass flux ranged from 30 to 220 g m-2 day-1. The particle composition ranged from 19 to 38% organic with little variation between three main sites. The data collected, in addition to local knowledge, was used to develop a procedure for laboratory scale roller table experiments which simulate surface oil and particle interaction. These experiments will be conducted May through August 2019 and paired with sediment trap data to quantify the potential for oil to sink via particle association. This presentation will summarize findings from field and laboratory work, and include a discussion on the relevance of this research to oil spill response decision-making in a larger context.

Angela Sarni, Ocean Engineering

Resolving the Role of the Dynamic Pressure in the Burial, Exposure, Scour, and Mobility of Underwater Munitions
Military testing and training around the United States has resulted in over 10 million acres of property in underwater environments, potentially containing military weapons. The weapons, or munitions, are difficult to locate, capable of sudden movement, and a danger to marine life and the public. Improved understanding of their mobility in underwater environments is vital for safe and cost-effective munition recovery. A pressure-mapped model munition (PMM) was designed and fabricated to resolve the role of dynamic pressure gradients on munition mobility. The PMM is an untethered instrument, containing all electronics necessary to retrieve, time, and store data. The PMM is capable of detecting and measuring surface pressure gradients, orientation and positional changes, and uses an acoustic tracker for retrieval after deployments.
The surface pressure mapping was accomplished using an array of sixteen 3mm-diameter, diaphragm pressure sensors. Orientation changes were recorded using an Inertial Measurement Unit (IMU). All data is stored to an on-board microSD card and recorded with time stamps. The PMM was evaluated through several full-scale laboratory and field experiments to determine its accuracy in detecting hydrostatic pressure changes, orientation changes, passing waves, and environmental changes, such as being submerged in a sand bed. The PMM was able to resolve both the overlying progressive wave signal as well as the deviations due to vortex shedding around the cylinder. Improvements in the original PMM design were implemented into a newly revised PMM 2.0. Further lab and field testing are underway to investigate the increased resolution of vortex shedding due to pressure gradients, and positional changes of the PMM. The results of this research suggest that vortex shedding may significantly contribute to the burial of free-standing objects. Additionally, these results can be more broadly applied to relationships between sediment and fluid structures.

Devin Thomas, Computer Science

New Tech for Old Problems: Building eDNA based solutions for species monitoring in Estuarine systems
Environmental DNA (eDNA), or DNA present in an environmental sample, is emerging as a powerful tool to detect species present in an ecosystem without having to actually capture and identify individual organisms. Fish, invertebrates, and other animals shed DNA through fragments of tissue, reproductive and waste products into the environment they live in.    High throughput sequencing of DNA extracted from environmental samples can identify hundreds of plant and animal species at relatively low cost.  These methods have the potential to transform monitoring and management of coastal systems, but we are really only beginning to understand how to effectively apply the technology to achieve useful, reproducible results.  This talk will focus on emerging eDNA methods for coastal and estuarine monitoring, including potential management applications, examples of relevant research, and development of standardized methods.   I will present examples from a pilot environmental eDNA monitoring program being implemented at several National Estuarine Research Reserve (NERR) sites in New England and Oregon, where metabarcoding and single-species PCR methods are applied to species detection with a focus on fish and crabs.  Sampling is being conducted in coordination with traditional monitoring programs including seine surveys, fish ladder counts, crab trapping and plankton tows to allow direct comparison to traditional methods.  A challenge in implementing eDNA monitoring is the interpretation and analysis of the results, I will discuss our bioinformatics approach, and efforts to provide accessible analysis tools for our end users.

Stephanie Gilooly, MS, Mechanical Engineering

Measurement of Dynamic Pressure Gradients on the Surface of Short Cylinders

Ben Gutzler, Ph.D. candidate, Biological Sciences

Follow your heart: using dataloggers to investigate behavior in freely-moving lobsters

Linas Kenter, Ph.D. candidate, Zoology

Strain evaluation of striped bass (Morone saxatilis) cultured at different salinities
Striped bass (Morone saxatilis) and their hybrids have been well studied and are widely cultured in freshwater ponds as food and gamefish. Recent industry expansion has generated an interest in strain-specific broodstock development for marine netpen and pond culture. In this effort, Atlantic and Gulf coast striped bass strains were cultured in recirculating aquaculture systems (RAS) at different salinities for up to two years and production and morphometric parameters (specific growth, feed conversion, fillet yield, condition factor and stripe patterns) were compared.  Striped bass juveniles produced from wild-caught broodstock from rivers in Nova Scotia, Delaware, Virginia, North and South Carolina, Florida, Texas and a selected, domesticated strain were reared in triplicate fresh (0 ppt), brackish (5 ppt) and saltwater recirculating (30 ppt) systems at two separate aquaculture facilities. After one year of age, a subset of fish were implanted with passive integrated transponder (PIT) tags, combined into a larger, “common-garden”, saltwater, recirculating system and monitored over an additional year. Parental broodstock and cultured offspring were fin-clipped and genotyped to identify juvenile family origin.  Final weights of fish after one and two years averaged approximately 0.5 and 2.5 kg, respectively and did not differ by water salinity. Growth rates and condition factors differed by strain, but condition factor was not correlated with fillet yield. Consistent with other studies, juvenile fish from South Carolina and Nova Scotia were found to be slow growing compared to migratory Atlantic and Gulf strains.  Mixed model analyses showed that family, and family by strain interactions were significant, but accounted for less growth variance than strain alone. These results indicate that family-based selection by strain may be useful in striped bass broodstock development programs.

Logan Maxwell, MS, Wildlife Conservation and Biology

Fitness consequences of hybridization in Saltmarsh and Nelson's Sparrows

Michael Smith, MS, Ocean Engineering: Ocean Mapping

Analysis of the radiated sound field of deep water multibeam echo sounders (MBES) for return intensity calibration using an underwater hydrophone array
MBES are tools used to gather geophysical information on the seafloor and watercolumn which are important for feature detection, identifying gas seeps, and characterizing the seafloor, among others. At high frequencies (>100Khz), MBES can be calibrated for their ensonification patterns in test tanks. However, deep water MBES feature long transmit arrays and varying geometries that make tank calibration impractical. The transmit arrays can be over 8m and have a far field range in the hundreds of meters. In addition, these systems use beam steering techniques to segment the swath into multiple sectors to mitigate ship motions, which complicates the radiated pattern and return intensity. This study will better characterize the radiated sound field of deep water MBES for return intensity calibration. A MBES survey was conducted using a Kongsberg EM122 MBES on the SCORE range, a submerged broadband hydrophone array. Hydrophones were spaced ~5km apart and were continuously recording during the survey. The EM112 is a multisector dual swath system operated at 12 kHz with CW waves. Hydrophone data were analyzed and the resultant radiated sound field was determined at different distances and angles.

Shannon-Morgan Steele, MS, Ocean Engineering: Ocean Mapping

End-fire Synthetic Aperture Sonar: A new technique for seafloor sub-bottom studies
The deep sound penetration desired for many acoustic seafloor sub-bottom investigations restricts sonar operation to low frequencies, as higher frequencies are rapidly attenuated with depth. Low-frequency sonar systems are characterized by large beam widths (typically 30-40 degrees), which limit their angular resolution and thus, significantly diminish their ability to detect small-scale lateral variations of the sub-bottom.  This talk will introduce end-fire synthetic aperture sonar (SAS), a new method for obtaining high-resolution measurements of the sub-bottom. End-fire SAS coherently combines multiple acoustic pings as the sonar moves through the water column, towards the seafloor, forming a narrow beam on the sediment that can be thought of as an “acoustic core”. This talk will discuss proof of concept for the end-fire SAS technique using results from simulations and the first end-fire SAS field experiments conducted this past winter.

Andrew Stevens, Ph.D. candidate, Computer Science (Best Oral Presentation for 2018!)

3D Habitat Analysis via Finite Element Modeling of Invasive Macroalgae
Outside environmental influences and invasive species are changing the makeup of ecosystems on the land and in the sea at an unprecedented rate.  Right here off of the coast of New Hampshire and the Gulf of Maine, invasive macroalgae (also known as seaweeds) are rapidly displacing native species and in some areas completely transforming the seafloor habitat.  We have developed a new analysis technique to measure and compare the 3D spatial architecture of seaweeds so that we may better understand the refuge spaces they can provide to small aquatic organisms.  This information can then be used to predict changes in organism populations that rely upon these seaweeds for protection as invasive varieties crowd out native communities.  Our analysis of three seaweed species models showed a high diversity of habitat within their 3D spatial structures, and by collecting field samples we have been able to validate our approach and demonstrate its viability.  By further developing this new analysis technique, we can begin to model entire communities of seaweeds as they change over time to learn how they might affect the entire food chain in a marine ecosystem.

Gregory Gilbert Taylor-Power, MS, Mechanical Engineering

Experimental investigation of the turbulent wake generated by wind turbine models in a large boundary layer wind tunnel

Katherine Vera von Krusenstiern, MS, Oceanography

Predicting Bathymetric change in dynamic estuaries
Sediment transport is investigated at Hampton-Seabrook estuary, NH to evaluate the applicability of the Coupled-Ocean-Atmospheric-Waves and Sediment Transport (COAWST) numerical model to simulate the bathymetric change over annual timescales. The study area spans the near coastal region that includes the adjacent beaches and extensive back-bay channels extending inland for several kilometers. In this hindcast, the Regional Ocean Modeling System (ROMS) and the Community Sediment Transport Model (CSTM) are coupled within the COAWST to track the temporal stability of the seafloor. The model is forced by observed water levels at the seaward open boundary, and is verified with observations of sea surface elevation and vertical variation in currents at sensor locations, deployed in fall 2017. Model results are compared to an in situ bathymetric survey completed in fall 2016. Differences between the field and model simulated bathymetric change will be discussed in terms of hydrodynamic variations on spring-neap tidal cycles, specification of bottom boundary conditions, and sediment grain size distributions.

Hampton-Seabrook estuary is a vital economic, recreational, and ecological asset to New Hampshire. Due to the dynamic nature of the sediments, navigational channels and harbors are dredged regularly from infill of sediments by the Army Corp of Engineers. Numerical modeling offers a robust capability to predict morphologic change in dynamic environments and provides an important tool for assessing coasting resilience to vulnerable shorelines. This work is supported by the National Ocean and Atmospheric Association and the Office of Naval Research.

Wilton Burns, MS, Earth Sciences

Effects of small-scale turbulence on phytoplankton growth and metabolism. 
Our current understanding of how turbulence affects small planktonic organisms is based on fluid dynamic theory, ocean models, and laboratory experiments that often have conflicting results. Atmospheric models predict that global temperature rise associated with climate change will affect turbulence patterns within the marine photic zone, where phytoplankton reside. To investigate how small-scale turbulence affects growth (growth rates, cell counts and extracted chlorophyll, and nutrient quotas) and metabolism (production of transparent exopolymer particles (TEP)) of marine primary producers, phytoplankton in monoculture and natural assemblages were incubated under a range of turbulent treatments. Results indicate that early in exponential growth of the monocultures, cell-specific TEP was higher with increased turbulence. During mid- and late exponential growth, there were no measurable differences in phytoplankton growth and TEP production as a function of turbulence. However, nutrient quotas were higher in the more turbulent tanks in phytoplankton cells >15 µm in length. Data from this study suggest that changes in turbulence in marine photic zones could result in increased nutrient storage in larger phytoplankton cells, as predicted by numerical models, but may not greatly affect the global carbon cycle via changes in TEP production.

Melissa Gloekler, MS

Movement and Erosion of Alberta Bitumen along the Bottom as a Function of Temperature, Water Velocity and Salinity
While many trajectory models exist to predict the movement of oil floating in or on water, few are designed to address heavy oil on the bottom of water bodies. In addition, remobilization (erosion) of the material into the water column is also difficult to predict. While properties such as adhesion, viscosity and density of oil may be readily measured, the critical shear stress (CSS) and the effect of (current) velocity, salinity, and temperature are virtually unknown for most heavy oils. The Center for Spills and Environmental Hazards (CSE) has a 4,000 L annular flume, with a water depth of 0.43 m. An inner rectangular flume (1.2 m length, 0.2m width, 0.9 m height), placed inside the annular flume, was preceded by two flow straighteners to reduced turbulence and produce a uniform, one dimensional flow field. The current is generated by an electric thrust motor and measured in 3D by a Nortek AS (Norway) Vectrino II Profiling Velocimeter. A 20g circle of Alberta bitumen (SG = 0.998) was placed on a laminated grid (1cm2 square pattern) at the bottom of the straight flume. A total of 2.3mof water was then gradually added to the flume. The electric motor was started and the profiler began collecting data. Two cameras, placed along the side and above the oil, collected video of the erosions and length/width changes of the oil. Conditions were held steady for one hour once the desired current velocity was achieved. Temperatures, current velocity (X, Y, Z), and digital videographic data were collected during each run. Erosions and percent lengthening of the oil was monitored as a function of water temperature, salinity and velocity. The turbulent kinetic energy (TKE) method was used to calculate the bed shear stress (BSS). In addition to the expected impact of higher temperature on the movement along the bed and erosion into the water column, the viscoelastic and shear-thinning properties of the bitumen played a role in its behavior (lowering of viscosity at higher BSS slowing erosions and movement) and must be considered when predicting its behavior during a spill.

Meghan Hartwick, PhD candidate, Molecular, Cellular, and Biomedical Sciences

Estimating Seasonal Variation of Vibrio parahaemolyticus concentrations in Oysters from the Great Bay Estuary
The recent emergence of Vibrio parahaemolyticus disease in the Northeast US is a challenge for public health safety, resource management and industry regulation. Most V. parahaemolyticus strains are believed to be non-pathogenic and those that do cause disease are contracted from the consumption of raw or undercooked seafood and shellfish from warm water environments. It is believed that co-occurring climate change associated environmental trends may be an underlying factor behind this new disease pattern. Surveillance of V. parahaemolyticus concentrations and coincident environmental conditions in the Great Bay Estuary has produced a long-term data set that can be applied to identify to conditions that may contribute to V. parahaemolyticus population dynamics in this region. Non-linear, temporal and multivariate analysis were applied to environmental and climatic data to determine that surface water temperature, average pH, average chlorophyll a, maximum turbidity and salinity were key variables to estimate V. parahaemolyticus concentration in oysters from the GBE. Focused studies into plankton dynamics suggest season specific plankton communities that are significantly associated with the variation that is observed in V. parahaemolyticus populations in oysters. The application of these results provides the basis to characterize ecological relationships for V. parahaemolyticus in this region and will be used to develop forecasting models of risk conditions for industry, shellfish resource managers and public health agencies in the Northeast.

Joshua Humberston, PhD candidate, Earth Sciences

Estimating surficial seafloor mud fraction in the tidally dominated Little Bay using principal component analysis of acoustic backscatter envelope properties
Field observations from an Odom Echotrac vertical-incidence 200 kHz echosounder were used to estimate seafloor mud fraction (fractional sediment size distribution less than 62.5 mm) in a tidally-dominated estuary with sediment distribution ranging 0–78% mud. Observations were obtained in water depths ranging 0.5–24 m in the Little Bay, New Hampshire. Backscatter waveform envelopes associated with the first acoustic interaction with the seafloor were analyzed and defined by seven properties: maximum and mean intensity, waveform width, area, skewness, kurtosis, and leading edge rise time. The spatial variability in these properties were decomposed into orthogonal eigenvectors using standard principle component analysis. The spatial weighting of the first principal component (representing 95% of the variance) was compared to observed surficial mud fraction. A simple logarithmic curve fit to the data accounted for 41% of the variability and well estimated (13% RMS error) the spatial pattern of mud across the bay from deep channels (no mud) to the flats (high mud content). The calibrated logarithmic function is used to estimate mud fraction spanning the estuary. Systematic deviations from the model are associated with regions with lower sediment porosity. When these anomalous data are removed from the analysis, the logarithmic model accounts for 62% of the variance. Application of the model along two cross-estuary transects in the Great Bay (independent from model development) resulted in similar RMS errors (15%) in predicted mud fraction showing that the empirical model works well for the Great Bay region provided the same sonar and settings are used.

Christopher Hunt, PhD candidate, Natural Resources & Earth Systems Sciences

Coastal Alkalinity: What we know (and don’t know) about neutralizing Ocean Acidification 
Ocean Acidification (OA) is a complex problem in coastal waters, affecting a variety of stakeholder groups (commercial, environmental, governmental) across a wide range of spatial and temporal scales. Assessing and projecting OA impacts is difficult given the contributions of several processes, a lack of recent historical baseline data in many areas, and the dynamic nature of the coastal environment. Alkalinity is the ocean's primary buffer against climate-driven acidification.  While the alkalinity of the ocean has long been studied, the variability of alkalinity in the coastal zone and the processes affecting alkalinity have received less attention.  However, new technological advancements coupled with improved understanding of the chemistry of alkaline species may offer new insights into buffering against OA.  Researchers in the UNH Ocean Process Analysis Laboratory are currently conducting two projects examining coastal alkalinity across a variety of settings.  This presentation will discuss the state of knowledge regarding coastal alkalinity, outline the approach of each OPAL project, present new data and maps, and synthesize how these projects will advance our understanding of coastal alkalinity and acidification.

Kara Koetje, MS, Ocean Engineering

Boundary Layer Dynamics in the Great Bay: Working Towards Resolving Estuarine Nutrient Fluxes
Quantifying the coupled physical and geochemical processes in the fluid-sediment interface is critical to managing coastal resources. This is of particular importance during times of enhanced hydrodynamic forcing where extreme tide or wind events can have a significant impact on water quality. A combination of field and laboratory experiments were used to examine the relationship between large-scale fluid shear stresses and geochemical fluxes at the fluid-sediment interface in the Great Bay Estuary, New Hampshire. Sediment geochemical measurements paired with flow field observations over several tidal cycles provide nutrient load estimates for the Bay. Sampling during typical tidal flow conditions along estuary-wide transects, an unexpected rotational flow field in the near-bed region of the water column was observed, which could have significant impact on the resultant nutrient release and nutrient budget estimates.

Meghan Owings, MS, Biological Sciences

Effects of the biomedical bleeding process on the behavior and physiology of the American horseshoe crab, Limulus polyphemus.
The hemolymph from the American horseshoe crab, Limulus polyphemus, is used to produce Limulus Amebocyte Lysate (LAL), which is used to test medical devices and vaccines for Gram-negative bacteria. This process has a 10-30% mortality rate, as well as several sublethal impacts. The goals of this study were to: 1) investigate the effects of the bleeding procedure on the behavior of horseshoe crabs in their natural environment and; 2) determine which bleeding process stressors (blood loss, air exposure, or increased temperature) have the most deleterious effects. For the field study, 14 control and 14 bled animals were fitted with ultrasonic transmitters and released into the Great Bay Estuary, and their depth preferences and locomotor activity were recorded from May-December of 2016. Lab experiments were conducted in outdoor tanks where animals were exposed to combinations of stressors. Accelerometers were attached to 64 animals to measure activity; and blood samples were repeatedly drawn to monitor hemocyanin levels. The telemetry study showed that control and bled animals exhibited similar activity patterns and seasonal migrations with females being slightly more impacted by the bleeding process in the first few weeks after they were released. In the lab, hemocyanin concentrations and activity were significantly impacted by different combinations of stressors, but not individual stressors. We hope that when this study is completed, the findings can be utilized to more sustainably bleed horseshoe crabs.

Lindsey Williams, PhD candidate, Natural Resources & Earth Systems Sciences

Information needs of coastal decision-makers and resource users: an exploration of information flow, timescale, and systems perspectives
Despite increasing calls to connect science with decision-makers, challenges remain in facilitating the flow of information across sectors.  In some cases, these challenges stem from lack of resources or other capacity limitations, in others from a fundamental lack for awareness of what information is most needed by decision makers and how information flows between groups.  In this study, we focus on the information needs and sources as reported by business and government decision makers in coastal New England.  Through analysis of semi-structured interviews, we focus on what types of information needs are identified and what sources of information business and government decision-makers rely on for their jobs.  Within these sectors, we also explore 1) the timescale of the information needs as context for understanding how the different sectors conceptualize the challenges they face, and 2) the systems scale as context for understanding conceptualization of the system within which they operate. If we are to meet the calls for management relevant science and science based decision-making, understanding these factors of information flow will be a key component.

Kaitlin Van Volkom, MS, Biological Sciences

Effects of introduced prey species on the growth and reproduction of the blood star, Henricia sanguinolenta
Henricia sanguinolenta is a native generalist predator that consumes sponges during the fall and spring months. Historically, in the summer and the fall months, these animals feed on detritus and filter particles from the water column. However, after the invasion of several tunicate species, these animals had the opportunity to feed on another prey species during the warmer months when food is less abundant. The goals of this study were to 1) monitor the percent cover of prey species throughout the year 2) determine sea star feeding patterns, and 3) evaluate the effect of diet on growth and reproduction. A field site was surveyed monthly to evaluate the percent cover of tunicate species, and instances of feeding were recorded. In a lab setting, sea stars were fed four different diets for six months. They were fed a combination of sponge and tunicate species that represented the historical and proposed current diet. They were weighed every two weeks, and at the end of the experiment the gonads and pyloric caeca were weighed.

Elizabeth Weidner, MS, Earth Sciences (Best Oral Presentation for 2017!)

Estimation of Marine Seep Flux on the East Siberian Arctic Shelf
An estimated 1400 gigatons of methane are held in subsea reservoirs on the shallow (<50 m average depth) Eastern Siberian Arctic Shelf (ESAS). Marine gas seeps and high methane concentrations in surface waters indicate these reservoirs are releasing methane via ebullition. Bubbles ebullated from the ESAS seafloor have a relatively short pathway through the water column and can facilitate the transport of methane directly to the atmosphere without oxidation. Methane seeps were mapped with a calibrated broadband split-beam echosounder on the ESAS in order to directly and quantitatively address the magnitude of methane flux and the fate of rising bubbles. Acoustic measurements were made over a broad range of frequencies (16 to 29 kHz), which allowed for very high range resolution and the identification of single bubbles in the water column. Seep bubble size distribution (BSD) were determined by exploiting bubble target strength models over the broad range of frequencies. By coupling BSD with bubble rise velocity measurements, made possible by split-beam target tracking, gas flux can be estimated.

Jessica Carloni, MS, Natural Resources, Wildlife Conservation & Biology

Identifying Foraging Locations of a Pelagic Seabird in Coastal New Hampshire

Joshua Carloni, MS, Zoology

Factors Influencing the Distribution of Ovigerous American Lobsters

Eric Doherty, MS, Ocean Engineering

The Memorial "Living Bridge" Project: Tidal Energy fron the Piscataqua River

Steve Eayrs, PhD candidate, Natural Resources & Environmental Studies

Facilitating Change in the New England Groundfish Fishery: Application of the Kotter Model for Organizational Change
This study applied organizational change management theories and principles to understand the appetite and attitudes of fishermen to change, including the Paradox of Fishermen. It also evaluated the efficacy of industry groups that serve to facilitate change on behalf of fishermen against the renowned Kotter model for organizational change, and it developed a new, comprehensive change management model to facilitate change in the New England groundfish fishery.

Sara Edquist, PhD candidate, Zoology

Spatial and Temporal Distribution of a Fish Parasite and its Intermediate Hosts in Great Bay Estuary

Ian Gagnon, MS, Mechanical Engineering

The UNH Living Bridge Tidal Energy Conversion System
A tidal energy conversion system was designed to power an array of smart infrastructure and estuarine sensors on Portsmouth, NH’s Memorial Bridge. The purpose of this tidal energy conversion system is to demonstrate an emerging renewable energy technology, serve as a research tool, and increase public interest in S.T.E.M. as well as the United States’ critical energy and transportation infrastructure. The tidal energy conversion system consists of a crossflow hydrokinetic turbine, a floating turbine deployment platform, and two vertical guideposts that provide a mooring point between the turbine deployment platform and one of the bridge’s piers. A resource assessment was performed to determine the available energy that could be converted from the tidal currents at the deployment site. An energy management system was simulated to determine the potential for providing continuous power to the sensors. Expected loads were calculated to ensure that the tidal energy conversion system would perform as expected under local gravitational, wind, wave, and tidal current loading. As a part of a senior design project, a 1:13 Froude scaled model of the tidal energy conversion system and bridge pier was constructed and tested in a tow/wave tank to experimentally verify these loads.

Onni Irish, MS, Earth Sciences (Best Oral Presentation for 2016!)

Analysis of CLCS Reccomendations in Light of their Relevance to the Delineation of a United States Extended Continental Shelf (ECS) in the Arctic
Article 76 of the United Nations Convention on the Law of the Sea provides a mechanism by which a coastal State can extend sovereign rights over resources of the seafloor and subsurface outside of its 200 nautical mile exclusive economic zone. In order for a coastal State to delineate this region, often referred to as the extended continental shelf (ECS), bathymetric, geophysical and geological data must be collected and analyzed to apply the mandates defined within Article 76. The coastal State must present its ECS delineation to a commission, called the Commission on the Limits of the Continental Shelf (CLCS). The CLCS reviews coastal States’ submissions and publishes recommendations as to whether they believe that the proposed ECS boundary is in accordance with Article 76. The United States has a potential ECS in the Chukchi Borderland region north of Alaska. This thesis examined two coastal States’ CLCS recommendations, the Kerguelen Plateau (Australia) and Vøring margin (Norway), to assess what criteria the CLCS utilized to classify seafloor highs, to forecast the impact these recommendations may have on a potential submission of the United States in the Chukchi Borderland region. This thesis has found that the CLCS requires a coastal State with seafloor highs that are connected to its continental margin to show that these features are (or not) morphologically and geologically continuous with the continental margin and landmass. If the coastal State can prove the seafloor high under question satisfies both of these criteria, it could potentially increase the coastal State’s final ECS outer boundary. Application of these criteria to the Chukchi Borderland region found that available data today could substantiate an argument that the Chukchi Borderland fulfills both criteria; however, further geological data needs to be collected from the northern extension of the Chukchi Borderland to support an Article 76 seafloor high classification.

Damian Manda, MS, Ocean Engineering

Autonomous Surface Vessel Developments for Hydrographic Survey

Maria Marin, MS, Oceanography

Observations of Surface Mixed Layer Variability in the Equatorial Pacific along the Coast of Ecuador

Melissa Melendez, PhD candidate, Oceanography

Local and Remote Forces Affecting the Carbonate Chemistry of Enrique Mid-shelf Reef at the Southwest Coast of Puerto Rico

Corey Sullivan, MS, Zoology

Design of an Integrated Multi-trophic  Aquaculture Raft

John Turner, PhD candidate, Mechanical Engineering

Very Large Experimental Wind Farm Array
Offshore wind proposal and installment is growing at a fantastic rate. In these necessarily large wind farms located near densely populated coastal cities, the governing fluid dynamics is not completely understood. An experimental study of a large offshore wind farm array is being conducted at the UNH Flow Physics Facility to better understand the flow around these devices.

Meagan Wengrove, PhD candidate, Ocean Engineering

Mightily Mobile Morphology at a Mega-nourishment
Observations of wave orbital ripples and current driven mega-ripples at two cross shore locations within the sub-tidal area of a mega-nourishment were made as part of the MEGA-Perturbation EXperiment (MEGAPEX). MEGAPEX was an internationally collaborative field experiment that took place in the fall of 2014 at the Sand Engine mega-coastal nourishment in the Netherlands. Installed in 2011, the purpose of the 4.5 km alongshore and 700 m cross shore perturbation is to use currents to naturally nourish the southern Dutch coast for a period of 20 years. Over the past 4 years the Sand Engine has dramatically changed shape as seen in Fig. 1a (initial shape in 2011) and Fig. 1b (shape today) (Stive, et al. 2013). On the large scale, the mega-nourishment is very dynamic; raising the question of the dynamic nature of its small scale morphology. This research investigates the forcing mechanisms behind small scale temporal and spatial morphologic change of ripples at the tip of the Sand Engine. Morphologic patterns were observed with two stationary rotating pencil beam sonars with a 3 m diameter footprint positioned with a 100 m cross shore spacing, just seaward of the shoreline and just shoreward of the sub-tidal sandbar. Concomitant hydrodynamic forcing was measured using an array of ADVs and ADCPs. Measurements were collected over a month long period, capturing two significant coastal storms, one of which was the remnants of Hurricane Gonzolo. Two-dimensional spectral analysis determined ripple orientation, wave length, and height (Fig. 1c and 1d). Results show ripples changing orientation and regime between orbital and anorbital bed states as a function of hydrodynamic forcing, a rarely observed phenomenon in previous works. Ripple wave length varied between 14 cm and 1.2 m (Fig. 1c and 1d) dependent upon the phase of the tide, sometimes complete transformation took place within as little as 20 minutes. Finally, during the passing of the remnants of Hurricane Gonzolo, with a 5 m offshore wave height, ripple wave lengths of 2.5 m were observed within this relatively shallow nearshore area.

Peter Bachant, PhD candidate, Mechanical Engineering

Studies of Cross-Flow Turbines at Large Laboratory Scale in the UNH Tow Tank

Eric Bajor, MS, Mechanical Engineering

High-Frequency Broadband Seafloor Backscatter in a Sandy Estuarine Environment

Emily Carlson, MS, Ocean Engineering

Near Bed Coherent Structures and Rippled Sea Bed Evolution Due to Short Waves

Anna Chase, MS, Zoology

The Influence of Substrate Material on Marine Fouling Community Development

Salme Cook, PhD candidate, Oceanography

Simulating Hydrodynamics on Tidal Mudflats

Tobias Dewhurst, PhD candidate, Mechanical Engineering (Best Oral Presentation for 2015!)

Dynamics of a Submersible Mussel Raft

Robert Eckert, MS, Zoology

Spatial Patterns of Spat Density in Relation to Distance from Native Oyster Reefs in Great Bay Estuary, New Hampshire

Shelley Edmundson, PhD candidate, Zoology

Channeled Whelk Research

Fiat Eren, PhD candidate, Mechanical Engineering

Pose Detection of Unmanned Underwater Vehicles (UUVs) Utilizing an Optical Detector Array

Meg Hartwick, PhD candidate, Natural Resources & Earth Systems

Marine Microbiology, Vibrio Ecology and Population Dynamics in the Great Bay Estuary

Scott Loranger, PhD candidate, Oceanography

Acoustic Properties of Submerged Oil Droplets

Elizabeth Morrissey, MS, Zoology

Clash of the Crustaceans: Interactions Between Green Crabs and Lobsters in the Great Bay Estuary

Ashley Norton, PhD candidate, Earth and Environmental Sciences

Developing Acoustic Methods for Characterizing Eelgrass Beds in Great Bay