Short-term effects of nereid polychaete size and density on sediment inorganic nitrogen cycling under varying oxygen conditions

Marine Ecology Progress Series

Jeffrey C. Cornwell¹  Jennifer A. Bosch¹  W. Michael Kemp¹ 

关键词: Polychaetes;    Nitrogen cycling;    Sediment biogeochemistry;    Bioirrigation;    Hypoxia;    Denitrification;    Alitta succinea;   

DOI  :  10.3354/meps11185

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Chronic eutrophication and expanding seasonal hypoxia (O₂ < 63 µM) in estuaries like Chesapeake Bay have altered benthic faunal communities in favor of opportunistic species that can quickly populate organic-rich sediments following hypoxic events. It has been suggested that the biogenic activity of polychaetes can stimulate microbial ammonification, nitrification, and/or denitrification in estuarine sediments as well as increase the fluxes of inorganic nitrogen (NH₄⁺, NO₂^-, NO₃^-, N₂) across the sediment-water interface. Results of 2 laboratory experiments with the opportunistic polychaete Alitta (Neanthes) succinea were used to quantify the short-term influence of density and size of surface-feeding polychaetes on denitrification and sediment-water fluxes of inorganic nitrogen under varying oxygen conditions. This study shows that polychaete enhancements of O₂ and nitrogen fluxes were strongly correlated with total animal biomass. Fluxes of O₂, NH₄⁺ and N₂ were stimulated by presence of animals for both larger and smaller worms, but per capita effects were greater for the deep-burrowing larger polychaetes. With the onset of hypoxic conditions, all density treatments had reductions in O₂, NH₄⁺ and N₂ fluxes, with the high-density treatment showing the greatest change. Denitrification efficiency  was 33% higher for experiments with large worms than for smaller worm treatments, suggesting that the former were more effective in removing fixed nitrogen.

【 授权许可】

Unknown