NUTRIENT AND METAL ACCUMULATION IN A FRESH-WATER TIDAL MARSH

Stratigraphic records from sediment cores collected in a freshwater ti dal marsh and in the estuary up stream and downstream from the marsh w ere used to determine the accumulation of nutrients and trace metals o ver long time periods. Analysis of pollen and seeds show that the high marsh has formed only within the past 100 yr, following increased sed imentation rates in the area. Variations in nutrient and trace metal a ccumulations over several decades show that pollutants from agricultur al runoff and wastewater discharge are stored to a greater extent in h igh-marsh than in low-marsh sediments. Greater accumulation rates in t he high marsh are probably related to its greater sedimentary organic carbon concentration.