昌黎近岸海域扇贝养殖区沉积物-水界面溶解无机氮磷及尿素扩散通量研究

分别于2015年12月、2016年4月和2016年9月，分3个航次采集了昌黎近岸海域扇贝养殖区沉积物柱状样品和原位底层海水，通过实验室培养法对该水域沉积物-海水界面DIN，DIP和尿素的扩散通量进行了测定。结果表明，昌黎近岸海域扇贝养殖区沉积物-海水界面DIN的扩散通量平均为52.72 μmol/（m2·h），DIP年平均通量为0.074 μmol/（m2·h），尿素年平均通量为1.00 μmol/（m2·h），扩散方向总体表现为从沉积物向上覆水扩散。昌黎近岸扇贝养殖区沉积物-海水界面尿素的通量为胶州湾通量的2~3倍，为黄海通量的2倍多，沉积物所提供的尿素为北戴河抑食金球藻褐潮的爆发提供了可能。沉积物每年向养殖系统输入的DIN总量估算为1680.73 t，溶解无机磷为2.36 t，尿素为136.66 t，表明沉积物是昌黎近岸海域扇贝养殖区水体氮磷，尤其是溶解无机氮和尿素的重要输入源。

Study on the diffusion fluxes of dissolved inorganic nitrogen phosphorus and urea across sediment-water interface in scallop culture area of Changli coastal waters

Three cruises were conducted in the scallop cultivation area of Changli coast in December 2015, April and September 2016; respectively, to collect the sediment cores and in situ bottom seawater. The diffusion fluxes of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and urea across sediment-seawater interface were measured by incubation experiment in laboratory. The average diffusion fluxes of DIN, DIP and urea across sediment-water interface were 52.72 μmol/(m2·h), 0.074 μmol/(m2·h) and 1.00 μmol/(m2·h), respectively, which showed obvious diffusion trend of nutrient from sediment to overlying water. The diffusion flux of urea in Changli scallop culture area was two to three-folds of that in Jiaozhou Bay and more than twice as much as that in Yellow Sea, which increased the possibility of brown tides caused by Aureococcus Anophagefferens. The annual fluxes of DIN, DIP and urea from sediment to water were estimated to be 1680.73 t, 2.36 t and 136.66 t respectively, which indicated that sediment was a major source for nutrient input, especially for DIN and urea.