An Evaluation of Candidate Measures of Biological Effects for the National Status and Trends Program (Classic Reprint)

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Excerpt from An Evaluation of Candidate Measures of Biological Effects for the National Status and Trends ProgramAnalyses of benthic communities were performed with two methods: traditional taxonomic analyses of animals collected with a grab sampler and retained on a 1-millimeter (mm) screen, and analyses of horizontal sediment profiling photographs taken with a remotely operated camera. The taxonomic analyses showed that the benthos were very similar among the three stations sampled at each site, but quite distinct among the sites. Total abundance, species richness, measures of total biomass, and indices of dominance and species diversity all indicated significant differences among sites. Molluscs were dominant at one site, polychaetes at another (the reference site), and crustaceans were dominant at two others. No data are available thus far for the most contaminated site. The major differences in benthos composition among sites could be attributable to natural types of stress such as periods of lowered salinity or scouring, as well as to differences in chemical contamination.A survey of 69 sites in the San Francisco Bay estuary was performed with a sediment profiling camera. A variety of sedimentological and biological parameters was recorded during analyses of the photographs. There were 4 of the 69 sites which corresponded with those sampled for bioassays, benthos, and chemical analyses. Signs of sediment organic enrichment or anoxia were recorded at very few of the sites. Some sites in the peripheral waterways of Redwood Creek, Oakland Inner Harbor, and Richmond Harbor showed indications of enriched sediments. Among the four sites sampled for toxicity, benthos, and chemical analyses the most contaminated site showed several indications of slightly elevated organic enrichment and contamination by bacterial indicators of sewage. The successional stage in benthic communities at that site, however, was not remarkably different from that at the other three sites. The sediment profiling photography technique provided data quickly on important characteristics of the surficial sediments.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.