Past Graduate Research Symposium Oral Presentations

Presentations are listed alphabetically by the last name of the presenter.

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 2.3m3 of 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