Wednesday, All Day in Poster Hall
, Thursday, All Day in Poster Hall
(subject to change)
Benthic conditions in shallow estuaries are closely linked to the activity of benthic invertebrates. Prior studies have demonstrated the capacity of certain species to significantly alter sediment redox status and rates of nutrient regeneration and release. Feedbacks between invertebrates and sediment processes could affect the progression of eutrophication by reducing anoxia in sediments and by altering nutrient availability. However, because few studies have tested the effects of invertebrate density and species composition on sediment processes, it is not clear how spatial or temporal variation in invertebrate abundance and diversity will affect ecosystem response to eutrophication. In this study, we assessed the relationship between density and various sediment processes and the relative importance of density versus diversity. In laboratory microcosms containing representatives from two functional groups, gallery diffusers (deep burrowing polychaetes) and biodiffusers (bioturbating bivalves), we measured fluxes of dissolved oxygen, dissolved inorganic carbon (DIC) and nutrients (ammonium, nitrate, phosphate and silica), concentrations of DIC, ammonium and sulfide in porewater and microalgal chlorophyll. Our results demonstrate the importance of accounting for both invertebrate density and species composition when evaluating the response of coastal systems to eutrophication.
