Graduate Research Symposium 2016 Presentation Topics

Ocean Engineering

 

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

Contact: Eric Doherty, eam45@wildcats.unh.edu

 

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.

Contact: Ian Gagnon, ifh2@wildcats.unh.edu

 

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.

Contact: John Turner, johnjturnerv@gmail.com

 

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.

Contact: Megan Wengrove, meagan.wengrove@gmail.com

Oceanography

 

Model-Field Data Comparison of Flow Structure in the Great Bay Estuary, New Hampshire

Contact: Salme Cook, sc10@wildcats.unh.edu

 

Autonomous Surface Vessel Developments for Hydrographic Survey

Contact: Damian Manda, damian.manda@noaa.gov

 

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

Contact: Maria Marin, mjm2015@wildcats.unh.edu

 

Observations of Seasonal Changes and Storm Effects in a Bedrock-Influenced, Paraglacial Coastal System: New Hampshire

Coastal systems are undergoing increasing pressure due to growing anthropogenic influences, accelerated eustatic sea-level rise, and more intense storms due to climate change. Consequently, a thorough understanding of coastal processes and sediment dynamics is necessary to create and maintain a sustainable balance between human influences and coastal environments. Like many other areas in the northeastern United States, the New Hampshire coastal region is heavily developed and features almost continuous engineering structures along the entire coast. Despite the extensive development, the New Hampshire coast has not been systematically studied to evaluate changes in beach morphology and sedimentology on seasonal bases nor in response to storms. To address these needs, monitoring stations have been established along the New Hampshire coast to study beach morphology, volumetric changes, sediments, and morphodynamics. Beach profiles are being measured primarily utilizing a GPS rover system. Each beach has been profiled at approximately bimonthly intervals, with additional surveys before and after high energy events. In addition, an uncertainty analysis was conducted. Initial profiling results indicate significant changes in beach elevation in response to relatively weak events.

Contact: Kaitlyn McPherran, kam2026@wildcats.unh.edu

 

Developments in Eelgrass Mapping Methodology Using Hydrographic Multi-beam Sonar

Our goal is to develop a data collection and processing methodology for water column backscatter data collected with a multi-beam echo-sounder to determine presence/absence, percent cover, maximum depth limit, and canopy height of eelgrass beds. Acoustic eelgrass mapping is of particular use in deep waters and turbid estuaries, where aerial imagery does not reveal the necessary detail for analysis. Presented here are updates to this project, including fieldwork completed in the summer and fall of 2015. The three main updates to the project are:
- More comprehensive delineation of the deep edge of eelgrass beds in Portsmouth Harbor
- Trials of a remotely-operated survey vehicle with the same sensor package used for our boat-based multi-beam surveys over eelgrass beds
- Extension of canopy and bottom picks further out across the swath of the multi-beam

Contact: Ashley Norton, anorton@ccom.unh.edu

 

Acoustic and Geomorphological Signatures of Gas Seeps on the East Siberian Margin

Rising hydrocarbon gas concentrations in the atmosphere are strongly linked to global warming. In the next century, significant amounts of hydrocarbons will be transport from the ocean to the atmosphere via thawing of flooded permafrost. The East Siberian Arctic Shelf (ESAS) holds 80% of the world's flood permafrost and is at risk of massive release due to bottom water warming. Gas released from permafrost is transported by gas seeps through the ocean; however, historically the magnitude of this gas flux has been difficult to quantify.

This research aims to estimate the total gas flux from a region of the ESAS, Herald Canyon, via acoustic and geomorphological characterization of gas seeps in the area. Data was collected with three acoustic systems (EM122 multibeam echo sounder, SBP120 subbottom profiler, and EK80 split-beam sonar) onboard the Oden, during the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) program.

53 seeps have been identified in the vicinity of Herald Canyon. Together, the EM122 high-resolution multibeam bathymetry and SBP120 chirp subbottom profiling data, provide the spatial and geologic context of the gas seeps. The EK80, which makes acoustic measurements over a broad range of frequencies, can identify individual bubble scatters. This enables estimates of bubble size distribution and rise velocity measurements in certain seeps; ultimately providing gas flux estimates. The combination of three data sets offers the opportunity to link seep flux measurements to geomorphological setting. The geomorphological setting can further be linked to local and regional geologic processes determined from seafloor morphology and subsurface structure. These links will help define our knowledge of the transport of hydrocarbon gas from flooded permafrost to the atmosphere.

Contact: Liz Weidner, eweidner@ccom.unh.edu

 

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.

Contact: Onni Irish, oirish@ccom.unh.edu

 

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

Contact: Melissa Melendez, mm19@wildcats.unh.edu

 

 Development of a Late Quarternary Depositional Model of a Paraglacial Estuarine Embayment, Portsmouth Harbor and Approach, New Hampshire

Contact: Kelly Nifong, knifong@ccom.unh.edu

Biological Sciences

 

A Hostile Takeover in the Salt Marsh: Invasive Snail Threatens Essential Plant Species

Surveys and experiments improved our understanding of the interactions occurring between two ecosystem engineers, Littorina littorea and Spartina alterniflora, in a fringing salt marsh along an eroding shoreline (York ME). The common periwinkle (L. littorea) is an invasive snail that destabilizes surface sediments and will often climb Spartina alterniflora, creating radulations as it grazes, which can weaken and kill the plant. Due to its ability to withstand regular inundation, S. alterniflora is the cornerstone species responsible for sediment trapping and marsh establishment, making it critical for coastal zone protection from erosion and sea level rise. As a result, the outcome of L. littorea and S. alterniflora interactions could have consequences for intertidal shorelines across New England. Snail densities reached 616 snails m-2 at our research site and tended to be greater in vegetated areas. Research questions for this study include: What is the maximum number of snails the average stand of S. alterniflora can sustain before experiencing significant biomass loss? Can N enrichment stimulate plant growth to overcome the snail driven biomass loss? What are the best plant protection strategies? Initial results show that the presence of snails reduced new shoot growth by 54%, while N enrichment increased new shoot growth by 48%. Since sea level rise and human encroachment both impact coastal marshes, preservation and restoration of remaining marshes is a priority and better understanding of community dynamics could improve restoration methods and management strategies to support healthy salt marsh ecosystems where L. littorea is present.

Contact: Devin Batchelder, dkb2001@wildcats.unh.edu

 

Identifying Foraging Locations of a Pelagic Seabird in Coastal New Hampshire

Contact: Jessica Carloni, Jessica.Carloni@wildlife.nh.gov

 

Factors Influencing the Distribution of Ovigerous American Lobsters

Contact: Joshua Carloni, joshuacarloni@hotmail.com

 

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.

Contact: Steve Eayrs, sjn57@wildcats.unh.edu

 

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

Oyster restoration aims to restore the ecological functions of native oyster reefs. Understanding how proximity to a native oyster reef affects recruitment patterns will assist in restoration site selection. In this study, spatial patterns of oyster recruitment were studied at three native oyster reefs in Great Bay Estuary. Mesh cages used for sampling oyster spat were placed on native reefs and at 200, 400, 600, 800 and 1000 meters upstream and downstream of native reefs. There was a significant decrease in spat densities as proximity from a native reef increased, while recruitment was not significantly different upstream or downstream from a native oyster reef. Results suggest that restoration efforts should consider extendin the natural boundary of native oyster reefs to provide the greatest potential for natural recruitment and thus long-term reef development.

Contact: Robert Eckert, robert.eckert@wildlife.nh.gov

 

Effects of Biodiversity on Sand Dune Systems of Plum Island, Newbury, Massachusetts

The impacts of Superstorm Sandy on coastal resources of the eastern United States have brought the importance of resilient sand dune systems into focus. While dunes are primarily dominated by American beachgrass (Ammophila breviligulata), a host of other native species commonly occur in these systems, providing diversity and habitat complexity that is often not recognized or incorporated into dune restoration initiatives, and could benefit sites where dune die-off is a concern. We sought to explore the importance of biodiversity on dune resiliency by using a variety of native species (in addition to A. breviligulata) to stabilize and revegetate dunes on the north shore of Massachusetts. Field experiments were used to determine which native dune species may be well suited for restoration by recording plant survivorship, growth rate, and relative ability to trap and accrete windblown sand in foredune habitats. We also compared differences in sand accretion capability or a single species (A. breviligulata only) versus low diversity (A. breviligulata with Solidago sempervirens) and higher diversity plots (A. breviligulata with S. sempervirens, Lathyrus japonicus, and Cakile edentula). Finally, diversity and percent cover were compared between healthy, natural dunes, restoration areas and dunes exhibiting signs of dune die-off. Based upon preliminary results, S. sempervirens and L. japonicus appear to be best-suited for restoration plantings. However, relative sand accretion was not affected by diversity level (low or high). As expected, diversity and percent cover were greatest in the control sites, compared to the restoration areas and dunes with die-off.  While it is clear that the benefits of diversity (structural, habitat, and ecological complexity) are essential to maintaining functional coastal ecosystems, the quantitative effects of diversity on dune resiliency will require further study to determine the best practices for restoration efforts.

Contact: Natalie Feldsine, nay53@wildcats.unh.edu

 

Effect of Salinity on Respiration Rates of Juvenile Cyclopterus lumpus

The lumpfish (Cyclopterus lumpus) is a commercially important species in Iceland and the Netherlands, where it is fished for roe which is used for caviar. Moreover, several recent studies have shown that lumpfish juveniles are useful cleaner fish in the Atlantic Salmon aquaculture industry. Despite the importance of the species, little is known about its ecology. This study is examining how one environmental variable (salinity) impacts the oxygen consumption of juvenile lumpfish. To determine this, juveniles were exposed to five salinity treatments (10, 15, 20, 25, 20 ppt) and oxygen consumption rates were measured. Standard metabolic rates (SMR) were calculated using SMR = (V*∆Cwo2)/ (∆t*Mf), where ∆Cwo2 is the slope of the decrease in dissolved oxygen, V is the volume of the respirometry chamber, ∆t is the change in time, and Mf is the mass of the individual fish. Results showed that juveniles had higher SMR at both 20 and 25ppt. However, they were able to tolerate salinities down to 5ppt for a week without visual signs of stress. This information will be helpful in informing the management of coastal and fishery resources, as well as those who wish to use lumpfish in aquaculture operations.

Contact: Jenna Rackovan, jlr2008@wildcats.unh.edu

 

Design of an Integrated Multi-trophic  Aquaculture Raft

Contact: Corey Sullivan, cjx86@wildcats.unh.edu

 

Floating to Recovery: Can Artificial Islands Provide Nesting Habitat for Saltmarsh Sparrows?

Tidal marsh birds are severely threatened by the impacts of rising sea levels on salt marsh ecosystems. Changes in vegetation, loss of nesting habitat, and increased tidal inundation will reduce, if not eliminate, the reproductive ability of marsh-nesting birds, such as the Saltmarsh Sparrow. Conservation actions are needed in the very near-term to identify solutions to mitigate nest flooding and maintain breeding populations until habitat is created in the longer term by accelerated marsh migration or other habitat restoration efforts. We designed a short-term management experiment for maintaining flood-free high marsh nesting habitat for Saltmarsh Sparrows through the use of artificial habitat islands. We installed four 4 ft x 8 ft floating island rafts, vegetated with Spartina patens and Spartina alterniflora in a marsh pool on Rachel Carson National Wildlife Refuge in Wells, Maine. Islands were monitored through the breeding season and winter. The islands remained free of tidal inundation and supported vegetation growth and expansion, suggesting that floating habitat islands hold promise as a method for mitigating nest flooding in tidal-marsh-nesting birds.

Contact: Bri Benvenuti, bar1@wildcats.unh.edu

 

Algal-bacteria Interactions and the Effects on Organic Matter Flux and Carbon Remineralization in the Ocean

Dissolved organic matter (DOM) produced during phytoplankton growth is processed and transformed by heterotrophic bacterial communities that produce extracellular enzymes in order to access and degrade organic matter substrates. Despite their important role for pelagic nutrient fluxes and energy cycling in the ocean, interactions between phytoplankton growth and activities of heterotrophic bacterial communities are rarely measured in concert. Separate laboratory experiments were conducted with non-axenic diatom cultures of Thalassiosira pseudonana, Thalassiosira sp. and Chaetoceros sp.; the latter two diatoms were recently isolated from the Northeast Pacific Ocean. Natural microbial assemblages were also sampled during a cruise into the Mid-Atlantic Bight to measure hydrolytic enzyme activities during phytoplankton growth. Diatom monocultures and mixed microbial communities were incubated under turbulence using oscillating grids and incubation times varied between 4 and 14 days. Subsamples were taken at different times during the incubation to determine bacterial and phytoplankton cell numbers, leucine-aminopeptidase activities, and concentrations of transparent exopolymeric particles (TEP) that form from microbial metabolites. The culture experiments revealed species-specific patterns in TEP formation and hydrolytic enzyme activities during the different phytoplankton growth phases. Heterotrophic responses within natural assemblages were more complex, reflecting hydrolytic activities of both bacterial communities associated with phytoplankton and free-living cells in the surrounding seawater.

Contact: Wilton Burns, wiltonburns@gmail.com

 

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

Contact: Sara Edquist, s.edquist@wildcats.unh.edu

 

Assessing Bottom Sediment Methane Concentrations and the Extent  of Anaerobic Oxidation of Methane in the Great Bay Estuary, New Hampshire

Contact: Dylan Lundgren, djl2008@wildcats.unh.edu