Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA 23062, United States.
Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy.
Mar Pollut Bull. 2018 Feb;127:524-535. doi: 10.1016/j.marpolbul.2017.12.003. Epub 2017 Dec 21.
As bivalve aquaculture expands globally, an understanding of how it alters nitrogen is important to minimize impacts. This study investigated nitrogen cycling associated with clam aquaculture in the Sacca di Goro, Italy (Ruditapes philipinarum) and the Eastern Shore, USA (Mercenaria mercenaria). Ammonium and dissolved oxygen fluxes were positively correlated with clam biomass; R. philippinarum consumed ~6 times more oxygen and excreted ~5 times more NH than M. mercenaria. There was no direct effect of clams on denitrification or dissimilatory nitrate reduction to ammonium (DNRA); rather, nitrate availability controlled the competition between these microbial pathways. Highest denitrification rates were measured at sites where both water column nitrate and nitrification were elevated due to high densities of a burrowing amphipod (Corophium sp.). DNRA exceeded denitrification where water column nitrate was low and nitrification was suppressed in highly reduced sediment, potentially due to low hydrologic flow and high clam densities.
随着双壳贝类水产养殖在全球范围内的扩张，了解其对氮的影响对于最小化影响非常重要。本研究调查了意大利 Sacca di Goro（菲律宾蛤仔，Ruditapes philipinarum）和美国东海岸（美欧帘蛤，Mercenaria mercenaria）贝类养殖与氮循环的关系。氨氮通量和溶解氧通量与蛤仔生物量呈正相关；菲律宾蛤仔消耗的氧气约是美欧帘蛤的 6 倍，排泄的氨氮约是美欧帘蛤的 5 倍。蛤仔对反硝化作用或异化硝酸盐还原为铵（DNRA）没有直接影响；相反，硝酸盐的可用性控制了这些微生物途径之间的竞争。在由于底栖桡足类（Corophium sp.）密度高而导致水柱硝酸盐和硝化作用升高的地点，测量到的反硝化作用速率最高。DNRA 超过了反硝化作用，因为水柱硝酸盐含量低，而在高度还原的沉积物中硝化作用受到抑制，这可能是由于水动力流量低和蛤仔密度高所致。
