National Status and Trends: Bioeffects Program - Kachemak Bay Database

This study was based on the sediment quality triad (SQT) approach. A stratified probabilistic sampling design was utilized to characterize the Kachemak Bay system in terms of chemical contamination, sediment toxicity and benthic infaunal community structure. The purpose was to define the extent and magnitude of toxicity and other biological effects associated with contaminants in the Kachemak Bay system. Five strata (Homer harbor, Western intertidal, Western subtidal, Eastern intertidal, and Eastern subtidal) were established in the shallow (less than 10 fathoms) northern area of the bay. Sediment samples were collected at multiple stations in each strata. A broad suite of sediment contaminants were analyzed at each station, including polynuclear aromatic hydrocarbons (PAHs), chlorinated pesticides including DDT and its metabolites, polychlorinated biphenyls (PCBs), trace elements, and butyl-tins Other parameters included grain size analysis, total organic/inorganic carbon (TOC/TIC), and percent solids. Characterization of infaunal assemblages and the abundance of organisms present in sediments provide additional information to help determine areas of degraded sediments. Whole sediment toxicity bioassays with two species of amphipod were conducted to test for overt contaminant toxicity. This project provides invaluable baseline data on sediment infauna species richness, chemical contamination and toxicity that is georeferenced and posted on the internet through the NOAA's National Status and Trends data portal.