Wednesday, All Day in Poster Hall
, Thursday, All Day in Poster Hall
(subject to change)
West Falmouth Harbor, Massachusetts is a shallow coastal estuary undergoing eutrophication due to increased nitrogen loading. Using experimental microcosms, we studied the impact of three species of benthic invertebrates common in West Falmouth Harbor (Nereis virens, Mercenaria mercenaria, Ilyanassa obsoleta) on benthic nutrient dynamics. We compared porewater profiles of sulfide, sulfate and ammonium in both high and low organic matter sediments. Porewater sulfide and ammonium concentrations were significantly decreased by each of the three species, with N. virens having the largest effect. Additionally, in more organic sediment, the alteration of porewater chemistry was greater than in less organic sediment. This implies that benthic invertebrates have progressively greater impact on sediment nutrient dynamics as eutrophication leads to organic enrichment of sediments. We also observed slight reductions in organic matter in the presence of invertebrates, suggesting that these organisms may help facilitate removal of organic matter. Other studies have shown that sediment enrichment due to eutrophication reduces the abundance of large infaunal invertebrates. Thus, our study indicates that benthic macrofauna may play an important role in regulating sediment nutrient dynamics during early eutrophication of shallow estuaries, as long as the organisms are retained in the ecosystem.
