Joseph J. Vitaliano

Benthic Biological Processes and EH as a Basis for a Benthic Index

It is proposed that the common measures of benthic community condition can be augmented with a vertical EH profile taken through the benthic bioturbation zone. Sediment EH, an electrochemical measure of oxidized and reduced compounds in sediment porewater, measures the integrative consequences of all metabolic and transport processes of the benthic community. Biota, especially microbiota, metabolize carbon using a variety of electron acceptors, including O2, SO4 and some nitrogen and metal compounds. Motile benthic macrofauna ingest and transport particles, ventilate deep burrows and anoxic sediment with overlying seawater while sedentary suspension-feeding fauna deposit suspended organic matter onto the sediment surface. Collectively, these metabolic and behavioral processes advect particles and seawater between bottom water and deep sediment and define the overall structure of porewater chemistry. That structure creates a full spectrum of biogeochemical conditions of solubility, reactivity, and microbial metabolism which remineralizes excess organic carbon and most organic contaminants, defines solubility of trace metals, and pushes the vertical EH profile toward oxidizing conditions. It is proposed that a standard EH probe inserted downward through the bioturbation zone will provide a general measure of this resulting porewater chemistry and thus the impact of feeding, irrigation, and metabolism of the total macro, meio, and microbenthic community. If such a measure can be validated it will permit extended measurement of community function and reduced efforts in measuring community structure.

Trace metals in eggs of winter flounder from Boston Harbor, a contaminated North American estuary☆

Abstract In 1987, the effects of contaminant levels in Boston Harbor, Massachusetts on the reproductive success of winter flounder were studied. As part of the study, the concentrations of 15 trace metals in laboratory-spawned eggs from adult winter flounder, taken from two stations in Boston Harbor, were measured using atomic absorption spectrophotometry. Trace metal concentrations in the eggs were low. There were no statistically significant differences between the two stations in the concentrations of any trace metal in the eggs. However, two fish captured from the Deer Island station had concentrations of cadmium in their eggs that were the highest reported for a flounder species to date. The concentrations of trace metals in eggs of winter flounder from Boston Harbor were similar to eggs of flounder species from other estuaries that exhibited different levels of habitat contamination. This suggests that differences in habitat contamination are not necessarily reflected in metal concentrations in laboratory spawned eggs.