Impacts of heavy metals on diatom (Bacillariophyceae) communities in Constitution Marsh and Foundry Cove, Cold Spring, New York, United States of America.

摘要

Foundry Cove and Constitution Marsh are located on the east side of the Hudson River, 85 km upriver from lower Manhattan. The marsh is a contiguous area of emergent marsh plants and mud flats. Between 1965 and 1971 cadmium and nickel were discharged into Foundry Cove by Marathon Battery Company. Cobalt was briefly discharged during this time. An estimated 53 metric tons of cadmium and nickel were deposited in the cove, which became a Superfund site in 1994. The dredging and restoration was completed in 1996.; Have heavy metals affected diatom communities in Constitution Marsh and Foundry Cove? Surface sediments were collected in triplicate from 12 sampling sites on eight occasions from September 18, 1997 to May 16, 1998. Three sampling sites were added to the 12 original sites during the May 30, 1998 collection and were sampled throughout the rest of the study for a total of 738 samples. Cadmium, nickel and cobalt levels were determined for each of the 738 samples. Diatoms were identified and enumerated for each collected sample. These data were analyzed using Bray-Curtis Similarity, MDS ordination, analysis of similarity, similarity of percentages and diversity indices.; Results show that the diversity of benthic diatoms is not affected by cadmium, nickel and cobalt at the concentrations found. In fact, the areas of the marsh with higher cadmium-nickel concentrations had similar diatoms to other parts of the study area. The dominant taxa, Navicula gregaria, Cyclotella meneghiniana and Cocconeis placentula var. lineata were present in similar proportions at all sampling sites. Navicula gregaria, however, occurred in the higher cadmium and nickel sites, stations four and five, in greater relative abundance than in other stations. This raises the question of whether this species is more tolerant of metals. Rarer species, then, were very important in differentiating the higher cadmium sites from the control sites.