IAN Seminar Series

As part of a larger study of multiple stressors in near-shore habitats, we measured water quality in 50 mid-Atlantic coastal bays and sub-estuaries. Total nitrogen and total phosphorus concentrations in estuarine water increased with the percentage of cropland in the watershed. Total nitrogen concentration also increased with the percentage of developed land but not as steeply as with cropland. Chlorophyll a concentrations increased at similar rates with increase in either developed or urban land. The land use composition of the local watershed clearly affected water quality in the bays and sub-estuaries, indicating that local efforts to reduce nutrient pollution will be needed to improve water quality. In 11 sub-estuaries we also analyzed mercury and organic contaminants in fish tissues. Some organic pollutants in fish, such as PCBs and pesticides, increased with developed land in the local watershed, depending on fish species, while some agricultural pesticides were associated with cropland. In contrast, me