Photos of the Long Island Sound

Research & Monitoring

2002 Research Project Descriptions

New Approaches for Assessing Mutagenic Risk of Contaminants in the Long Island Sound Environment

Investigators:
Dr. Anne McElroy, Stony Brook University
Dr. Lynn Mendelman and Dr. Richard Setlow, Brookhaven National Laboratory

The objectives of this project were to evaluate the potential capacity of contaminants in the sediments of Long Island Sound to cause mutations in vertebrates and to determine the types of mutations induced and the classes of contaminants responsible for these mutations. The researchers collected sediment samples from the Sound and identified those samples that were mutatoxic. Eggs from a fish species that is particularly susceptible to environmental mutagens were then exposed to the mutatoxic sediments from six sites. After the eggs hatched, the fish larvae were examined to determine the mutation frequency related to the sediment samples. Mutation frequency in the fish embryos increased after exposure to sediments from only one of the LIS sites. The sediment sample from this site contained extremely high levels of polycyclic aromatic hydrocarbons (PAHs). Results illustrate that transgenic embryos can be used to help quantify and characterize mutations induced by exposure to environmental mutagens. Data from this small-scale study also indicate that the mutagenic risk of LIS sediment contaminants to vertebrate organisms is generally low. The researchers recommended that additional work to evaluate the mutagenic risk of sediments at contaminated urban sites be conducted to substantiate their preliminary findings.
Final Report Summary
Final Report

Published paper related to grant: McElroy , A.E., A.D Bogler, D. Weisbaum, M. Norris, L.V. Mendelman, R. Setlow, and R Winn. 2006. Uptake, metabolism, mutant frequencies and mutational spectra in transgenic medaka embryos exposed to benzo[á]pyrene dosed sediments. Marine Environmental Research .62(2006): 273-277.

Phytoplankton Dynamics in Long Island Sound: Influence of environmental factors on naturally occurring assemblages

Investigators:
Dr. J. Evan Ward, University of Connecticut
Dr. Kevin Strychar, Dalhousie University
Dr. Gary Wikfors, National Marine Fisheries Service

The objective of this project is to determine how phytoplankton dynamics differ in Long Island Sound along an eutrophication gradient (from east to west) and with the seasons. The researchers are also examining which environmental factors (i.e., nutrients, hypoxia or temperature) are the best predictors of phytoplankton assemblages. Phytoplankton are important primary producers that fuel coastal marine food webs. Nutrient over-loading, eutrophication and pollution can alter phytoplankton abundance and community structure. Such changes can lead to the degradation of food webs that support commercially valuable finfish species. This work will help advance the understanding of linkages among nutrients, phytoplankton and hypoxia. This information will have important implications for the long-term management of Long Island Sound and for the development of strategies to protect and restore the Sound’s living marine resources.
Final Report Summary
Final Report

Saltmarsh-breeding Sparrows in Long Island Sound: Status and productivity of globally important populations

Investigators:
Dr. Chris Elphick and Dr. Margaret Rubega, University of Connecticut
Mr. Patrick Comins, National Audubon Society

The objective of this project is to compare a variety of methods for estimating saltmarsh sparrow abundance along the central Connecticut coast and identify the simplest, most cost-effective method for providing accurate population estimates. Saltmarsh sparrows are high priority species for bird conservation in New England. However, little is known about the status of these birds and methods for measuring their abundance are not well developed. Data gaps that these researchers are working to address include detailed information on population sizes, within-marsh habitat selection, and productivity. Evaluating the productivity of populations in key marshes is essential to determining the health of these populations and understanding the underlying environmental factors that influence reproductive success, breeding density and species occurrence is fundamental to effective management. Using data regarding what features influence nest site placement, the researchers are developing models that will be used to predict the consequences of a variety of habitat changes that may arise in the future and to compare alternative management scenarios. Data collected on marsh bird assemblages at each study plot is also being compiled by the researchers in order to evaluate options for developing useful indicators for the health of the bird communities in Long Island Sound saltmarshes.
Final Report Summary
Final Report

Additional information on this project is available at the following website:
http://hydrodictyon.eeb.uconn.edu/people/birdlab

Published paper related to grant: Gjerdrum, C., C.S. Elphick, and M. Rubega. 2005. What determines nest site selection and nesting success in saltmarsh breeding sparrows? Condor 107:849-862.

Water Column Oxygen Production and Consumption in Long Island Sound: Measurements and coupled bio-physical modeling

Investigators:
Dr. James Kremer and Dr. Nicole Goebel, University of Connecticut
Dr. Chris Edwards, University of California at Santa Cruz

The objectives of this project are to measure water column oxygen production and consumption rates for Long Island Sound and to develop a coupled bio-physical simulation model of the Sound. These researchers are directly measuring plankton oxygen metabolism during the critical summer months in order to further the understanding of the processes leading to hypoxia in Long Island Sound. This study will improve the development and interpretation of the water quality models applied to the Sound by providing field measurements of planktonic oxygen production and consumption rates. The researchers are also developing a new model with which the relevant biological and physical processes that lead to eutrophication and hypoxia in the Sound can be analyzed. The results of this work will help inform planning and management decisions regarding hypoxia in the Sound.
Final Report Summary

Published paper: Goebel, N.L., J.N. Kremer, and C.A. Edwards. 2006. Primary Production in Long Island Sound. Estuaries and Coasts. Vol. 29, No. 2 (April 2006): 232-245.

Western Long Island Sound Hypoxia: Isotope tracers of the East River nitrate pump

Investigator: Dr. Richard Fairbanks, Columbia University

The objective of this project was to assess the contribution of discharge from the East River to hypoxia in western Long Island Sound using isotope tracers of East River water and organic particulate matter. Isotope tracers, in addition to concentration data, allow researchers to identify the sources and mixing history of water and particulates entering western Long Island Sound. This researcher investigated the processes and pathways governing the sequestration of nitrogen and phosphate from the East River. Using isotopic tracers to follow the delivery of East River-derived nitrate and phosphate to the hypoxic region, a map of the concentration and volume of East River water in the western Sound during the development of hypoxia was produced. The unique results of this study indicate that four small, deep basins act as “hypoxia incubators” on the seafloor of the western Sound and that these basins spread hypoxia throughout the water column. Nitrogen isotope tracers demonstrate that the organic particulates sampled in the deep basins derive their nitrogen almost entirely from wastewater effluent. Oxygen isotope measurements of water molecules indicate that tidal mixing maintains a high percentage of East River water directly overlying the site of initial hypoxia in the western Sound. Isotope data also show that the eastward spread of low oxygen waters is due to tidal and current mixing with the extremely low oxygen waters pooling in the four deep basins. Based on these findings, the researcher recommends that managers target hypoxia abatement strategies at these four restricted basins in order to address the immediate source of the problem. It is also recommended that a hypoxia abatement experiment be conducted in the smallest basin using isotope and purposeful tracers.
Final Report Summary
Final Report

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