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Soft-Bottom Benthic Assemblages and Levels of Contaminants in Sediments and Biota at Gray’s Reef National Marine Sanctuary and Nearby Shelf Waters off the Coast of Georgia (2000 and 2001)

Author(s): Cooksey, C.; J. Hyland; W.L. Balthis; M. Fulton; G. Scott; D.Bearden


Publication Type: NOAA Technical Memoranda

Journal Title: NOAA Technical Memorandum NOS NCCOS 6

Date of Publication: 2005

Reference Information:

Extent of Work: 55

Keywords: Gray's Reef National Marine Sanctuary; South Atlantic Bight; Marine Benthic Communities; Georgia; Estuarine; Chemical Contaminants

Abstract: A series of studies was initiated to assess the condition of benthic macroinfauna and chemical contaminant levels in sediments and biota of the Gray’s Reef National Marine Sanctuary (GRNMS) and nearby shelf waters off the coast of Georgia. Four key objectives of the research are (1) to document existing environmental conditions within the sanctuary in order to provide a quantitative benchmark for tracking any future changes due to either natural or human disturbances; (2) to examine broader cross-shelf spatial patterns in benthic fauna and sediment contaminant concentrations and to identify potential controlling factors associated with the observed patterns; (3) to assess any between-year temporal variability in benthic fauna; and (4) to evaluate the importance of benthic fauna as prey for higher trophic levels. Such questions are being addressed to help fulfill long-term science and management goals of the GRNMS. However, it is anticipated that the information will be of additional value in broadening our understanding of the surrounding South Atlantic Bight (SAB) ecosystem and in bringing the knowledge to bear on related resource-management issues of the region. We have begun to address the first three of these objectives with data from samples collected in spring 2000 at stations within GRNMS, and in spring 2001 at stations within the sanctuary and along three cross-shelf transects extending from the mouths of Sapelo, Doboy, and Altamaha Sounds out to sanctuary depths (about 17-20 m). This report provides a description of baseline conditions within the sanctuary, based on results of the spring 2000 survey (Section II), and uses data from both 2000 and 2001 to examine overall spatial and temporal patterns in biological and chemical variables within the sanctuary and surrounding inner-shelf environment (Section III). Highlights of conclusions reported in Section II: ? Results of the initial spring 2000 survey indicated that, in general, chemical contaminants in sediments throughout GRNMS are at background levels, below probable bioeffect guidelines. The low sediment contamination is most likely attributable to the remote location of this offshore environment and the sandy nature of the substrate (e.g., absence of a silt-clay fraction). ? Contaminants in tissues of target benthic species within the Sanctuary are below human-health guidelines (where available) based on a limited sample population (10 fillets of black sea bass and 9 arc-shell composites). ? Both sediments and tissues contained trace concentrations of chemical contaminants associated with human sources (pesticides, PCBs, PAHs), demonstrating that such materials are making their way to the offshore sanctuary environment, either by air or underwater cross-shelf transport from land. ? The vast stretches of sands throughout the sanctuary support a highly diverse infaunal community, a finding which should change a frequent misconception that these “featureless” substra

Availability: Copy may be obtained from Cynthia Cooksey

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