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SPECIES-ABUNDANCE-BIOMASS RESPONSES BY ESTUARINE MACROBENTHOS TO SEDIMENT CHEMICAL CONTAMINATION.
Rakocinski, C. F., S. S. Brown, G. R. Gaston, R. W. Heard, W W. Walker, AND J K. Summers. SPECIES-ABUNDANCE-BIOMASS RESPONSES BY ESTUARINE MACROBENTHOS TO SEDIMENT CHEMICAL CONTAMINATION. JOURNAL OF AQUATIC ECOSYSTEM STRESS AND RECOVERY 7(3):201-214, (2000).
Macrobenthic community responses can be measured through concerted changes in univariate metrics, including species richness, total abundance, and total biomass. The classic model of pollution effects on marine macroinvertebrate communities recognizes that species/abundance/biomass (SAB) curves vary distinctively in a nonlinear manner with the magnitude of organic enrichment. For example, at moderate levels of organic enrichment, small-bodied opportunistic species boost the abundance curve, while species richness falls. Ratios among the metrics form useful indicators of how the community changes with organic enrichment. However, the classic SAB model is based on organic enrichment effects over small spatial and temporal scales, and the applicability of the SAB model to sediment chemical contamination and across broad natural estuarine gradients is largely unknown. Here, SAB responses were examined with respect to primary gradients in metals and organic chemicals based on an extensive dataset comprising 319 estuarine sites from throughout the northern Gulf of Mexico. Each SAB metric was first adjusted with respect to the three primary natural estuarine gradients, salinity, depth, and sediment silt/clay content. Adjusted SAB relationships varied in their details with respect to different classes of sediment contamination, but all types of SAB stress responses appear to exhibit similar basic characteristics. As in the SAB model, all three SAB metrics were notably low at the highest concentrations of both metal and organic-chemical contaminants. Moreover, rapid decreases in the B/A ratio with increasing contamination supported the concept that relatively long-lived, large-bodied, equilibrium taxa decline markedly at high concentrations of toxicants
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
GULF ECOLOGY DIVISION