2020 Research Project Descriptions

Projects will take place from 2021 to 2023

Can Watershed Land Use Legacies Inform Nitrogen Management?

Investigators: Ashley Helton, Chester Arnold, Emily Wilson, and David Bjerklie, University of Connecticut; Wilfred Wollheim, University of New Hampshire; Mary Becker and Chris Bellucci, CT DEEP; Paul Stacey, Footprints in the Water LLC
Grant Award: $487,391 plus $487,391 in matching funds

Past land use activities can be strong indicators of contemporary water quality, yet watershed management strategies often neglect the lag times associated with land changes. This project will work to develop a more complete understanding of land use legacies within the Long Island Sound watershed and how they interact with patterns of nitrogen dynamics and stream biointegrity to allow for more informed and improved management that better aligns with watershed processes. Three objectives will be pursued:

  • Developing a geospatial classification scheme of vulnerability to watershed land use legacies
  • Quantifying the influences of watershed land use legacies on present-day water quality
  • Engaging the public and resource managers in understanding how watershed land use legacies can guide better watershed management decisions.

Evaluating Thin Layer Placement in Long Island Sound Marshes Using a Multi-Scale Approach

Investigators: Beth Lawrence, Ashley Helton, and Chris Elphick, University of Connecticut; Min Huang, CT DEEP
Grant Award: $470,969 plus $245,238 in matching funds

Rising seas and limits to marsh migration pose serious threats to remaining Long Island Sound tidal marshes and the services they provide. Implementing restoration techniques that build elevation and promote coastal resilience, such as placement of sediments, is key to tidal marsh maintenance and a high priority for regional managers. This research will address the critical need for well-tested guidelines examining how sediment sizes and textures as well as tidal range alter the effectiveness of sediment applications for marsh restoration. The project will measure sediment, plant, and carbon flux responses to experimental treatments and compare responses in three marshes. These field experiments will help inform management decisions in real time and ultimately help enhance coastal resiliency. The project will evaluate whether small-scale placement experiments are representative of management-scale applications and promote better understanding of sea level rise, coastal wetlands, and marsh restoration among diverse stakeholders.

Can They Get Out? Loss of Connectivity for Juvenile Alewives Out-Migrating to Long Island Sound

Investigators: Eric Schultz, James Knighton, and Cary Chadwick, University of Connecticut
Grant Award: $231,013 plus $123,000 in matching Funds

Populations of anadromous river herring have been greatly impacted by the loss of connectivity to freshwater habitats due to dams and other anthropogenic barriers. Considerable resources have been put into restoring fish passage for upstream migration of adults, but barriers to out-migration of juvenile river herring have been largely overlooked. Low flows during summer and fall are regularly observed to prevent juvenile out-migration. The extent of the problem is unknown, and managers need to assess risks and evaluate potential interventions to improve passage. This project addresses this need through six steps: collecting existing data and environmental characteristics of the herring runs; characterizing the hydrological conditions of the herring streams; developing soil and water assessment tool models for the streams; surveying out-migrating juveniles in eight CT rivers; condensing the results into an interactive online tool and map viewer that managers can use to identify the risks of lost connectivity under various conditions; and promoting the tool among resource managers, municipalities and land owners to empower them to evaluate interventions that will reduce that risk.

Establishing Robust Bioindicators of Microplastics in Long Island Sound: Implications for Reliable Estimates of Concentration Distribution and Impacts

Investigators: J. Evan Ward and Sandra Shumway, University of Connecticut
Grant Award: $301,150 plus $150,575 in matching funds

Contamination of marine animals (including commercially important species) by microplastics is of growing concern to governmental and non-governmental groups, the aquaculture industry and the public. This project seeks to quantify the load and distribution of microplastics in Long Island Sound as an important first step in addressing these concerns. Laboratory and field studies will be conducted to determine if slipper snails and tunicates, which are non-discriminant particle feeders, can be used as bioindicators to estimate and monitor microplastic loads in Long Island Sound and other marine environments. In the project, slipper snails, tunicates and oysters will be exposed to different sizes, shapes and types of microplastics commonly found in the natural environment. Feces, pseudofeces and tissue will be analyzed to determine the proportion of microplastics ingested, rejected and egested, and gut retention time.

Quantifying the Ability of Seaweed Aquaculture in Long Island Sound to Remove Nitrogen, Combat Ocean Acidification, Improve Water Quality and Benefit Bivalves

Investigators: Christopher Gobler and Michael Doall, Stony Brook University: Kendall Barbery, GreenWave
Grant Award: $238,933 plus $131,984 in matching funds

This research seeks to explore if two warm-water seaweeds could be complementary to winter kelp farming for purposes of bioextraction of excess nitrogen, ameliorating coastal ocean acidification and reducing the incidence of harmful algal blooms. The research also seeks to understand if the production of Gracilaria and Ulva would benefit the growth of cultured bivalves. This will be done by growing kelp, Gracilaria and Ulva and multiple locations in New York and Connecticut waters and quantifying net nitrogen and carbon removal rates. It will also map changes in dissolved oxygen, ocean acidification, HAB concentrations and ecosystem metabolism in areas with seaweed aquaculture. The project will also quantify the growth, survival, settlement, condition and nitrogen bioextraction of nitrogen by Eastern oysters and blue mussels grown with and without seaweeds. Information on best practices for maximizing growth of seaweeds, nitrogen bioextraction, bivalve performance and water quality improvements will be shared in a guidance document and workshop.

Constraining Models of Metabolism and Ventilation of Bottom Water in Long Island Sound Using Oxygen Isotopes

Investigators: Craig Tobias and James O’Donnell, University of Connecticut
Grant Award: $649,386, plus $325,004 in matching funds

While efforts to reduce nutrient loads have reduced hypoxia in Long Island Sound, there is still a need to better understand how controls on bottom water oxygen and nutrient reduction translates into a hypoxia recovery trajectory. This project is designed specifically to inform how to improve models of bottom water hypoxia by using oxygen isotopes to tackle two fundamental questions:

  • How does vertical mixing affect bottom water oxygen?
  • How important is benthic oxygen demand?

This will be done through both field measurements and laboratory experiments to measure water column oxygen metabolism and quantify the vertical and horizontal mixing of oxygen. Laboratory experiments will measure the isotope effect of water column and benthic respiration associated with oxygen loss. The project will develop and validate a coupled hydrodynamic hypoxia simulation model of oxygen and its isotopic composition in the surface and bottom waters.

Improving Eelgrass Restoration Success by Manipulating the Sediment Iron Cycle

Investigators: Craig Tobias and Jamie Vaudrey, University of Connecticut; Chris Pickerell, Cornell Cooperative Extension
Grant Award: $323,404, plus $161,786 in matching funds

While many Long Island Sound embayments now have improved water quality that should make them suitable for eelgrass restoration, there is a difference between the acreage of habitat that could theoretically support eelgrass and where it has actually regrown or been restored successfully. Sediment is a key component that may have been overlooked and is a potentially limiting factor for eelgrass restoration efforts to move forward, which is a key goal of the Long Island Sound Comprehensive Conservation and Management Plan. To develop a new restoration management framework, this project will map sediment sulfide and iron gradients in relic eelgrass beds in the Niantic River Estuary, and correlate sulfide concentrations to other sediment variables to establish easy-to-measure proxies for sulfide for use in evaluation of potential eelgrass restoration. The project will then conduct experiments to test the effect of adding iron-oxide pellets, a cost-effective tool, to sediments on porewater sulfide and solid phase iron-sulfide mineral content. This method of iron amendments could potentially be easily integrated into existing restoration techniques.

Alkalinity of Long Island Sound Embayments

Investigators: Penny Vlahos and Michael Whitney, University of Connecticut; Peter Linderoth, Save the Sound; Katie O’Brien-Clayton, CT DEEP
Grant Award: $131,088, plus $181,205 in matching funds

Total alkalinity and aragonite saturation in river-fed embayments in Long Island Sound differ greatly based on water quality and land use patterns and have significant implications for shellfish yields. This project will conduct the first assessment of alkalinity in the Sound’s embayments, with the goal of measuring and analyzing four key variables in the carbonate alkalinity system: total alkalinity, pH, partial pressure of carbon dioxide and dissolved inorganic carbon. This will contribute to an understanding of the range of buffering capacity and resilience across the Sound to acidification and link this to nutrient loading and local conditions. The results will provide an in-depth analysis of spatial and temporal variability along with management-scenario testing. Maps of alkalinity and aragonite saturation will be developed by combining observations and simulation results to identify areas that are resilient or vulnerable to changes in pH across regions through engagements of stakeholder groups across the coastline. Additionally, the project will identify aragonite saturation rates at these embayments to determine the occurrence of low saturation periods that are a risk to shellfish.

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