Trace element concentrations among functional feeding groups in the estuarine food web in Middle Hempstead Bay, Long Island, New York
Estuaries are productive ecotones that are vulnerable to anthropogenic contamination due to human population density, overharvesting of marine resources, and an increase in urbanization and industrialization along coastlines. Most estuaries in the United States exhibit impaired water quality due to ongoing and legacy contamination. Middle Hempstead Bay is an estuarine ecosystem within the South Shore Estuary Reserve, on Long Island, New York, made up of densely clustered salt marsh islands that house multiple recreationally harvested (e.g., summer flounder, Paralichthys dentatus; blue crab, Callinectes sapidus; blue mussel, Mytilus edulis; and hard clam, Mercenaria mercenaria) and vulnerable species (e.g., piping plover, Charadrius melodus and diamondback terrapin, Malaclemys terrapin). This study investigated the concentration of six essential (Co, Cu, Fe, Mn, Se, Zn) and four nonessential (As, Cd, Hg, Pb) trace elements in sediments and in 27 estuarine species from Middle Hempstead Bay. Species were placed into functional feeding groups (FFGs) composed of species that feed or gain energy via the same general pathway; FFGs are commonly used to examine patterns in contaminant concentrations and behavior in food webs. Finally, differences in the tissue distribution of trace elements among four species [saltmarsh cordgrass (Spartina alterniflora), summer flounder, common tern (Sterna hirundo), and black skimmer (Rycops niger)] was examined. Within sediment, Fe had the greatest concentration, followed by Mn, Zn, Pb, Cu, As, Co, Se, Cd, and Hg. In addition, As concentrations exceeded sediment guidelines for NY State, and both As and Pb had concentrations higher than values reported in 2013 following Hurricane Sandy. Essential trace elements in biota generally exhibited greater concentrations than nonessential elements. Across FFGs, algae had significantly greater concentrations of trace elements known to biodiminish within the food web (Co, Pb) and piscivorous feeding groups were determined to have greater concentrations of elements known to biomagnify within the foodweb(Hg). For most elements, concentrations were greatest in the root, followed by the leaf and stem in saltmarsh cordgrass. Summer flounder had significantly greater trace element concentrations in liver tissue compared to muscle, except for Hg and Pb. Trace element concentrations were predominantly greatest in liver of common tern compared to muscle and feather. Black skimmer trace element concentrations were similar across tissues for Cd, Co, and Hg, with concentrations of the other seven elements varying across tissue type. This is the most comprehensive study of trace element concentrations in several trophic levels of the Middle Hempstead Bay food web. While this study did report sediment and biota trace element concentrations for Middle Hempstead Bay, future studies should include larger sample sizes and focus on investigating trace element concentrations among FFGs using food chains instead of complex food webs.
Estuarine, Estuary, Middle Hempstead Bay, South Shore Estuary Reserve, SSER, Trace element, Functional feeding group, FFG, Tissue distribution, Food web, Essential element, Nonessential element
Livingston, M. L. (2022). <i>Trace element concentrations among functional feeding groups in the estuarine food web in Middle Hempstead Bay, Long Island, New York</i> (Unpublished thesis). Texas State University, San Marcos, Texas.