苏北浅滩绿潮爆发早期营养盐的水平分布

The Saptial Distribution of Nutrients in Subei Shoal on the Early Stage of Green Tide

依据2016年5月、6月苏北浅滩海域两次调查资料分析了调查海域溶解态营养盐的结构与分布特征。结果表明:DIN(dissolved inorganic nitrogen,溶解无机氮)的主要存在形态是NO_3^-—N(nitrate,硝酸盐),NO_2^-—N(nitrite,亚硝酸盐)占DIN比重最少,DON(dissolved organic nitrogen,溶解有机氮)为TDN(total dissolved nitrogen,溶解态总氮)的主要存在形态,DOP(dissolved organic phosphorus,溶解有机磷)未检出。从N、P、Si的比值来看,调查海域属于磷限制。NO_3^-—N、PO_4^(3-)—P(phosphate,磷酸盐)、SiO_3^(2-)—Si(silicate,硅酸盐)浓度水平分布呈近岸高、远岸低的趋势;而NO_2^-—N、NH_4^+—N、DON的分布无明显规律。与5月相比,6月除NO-2—N浓度升高外,其他各项溶解态营养盐浓度均明显降低;NO_3^-—N、PO_4^(3-)—P、SiO_3^(2-)—Si的高值区向近岸方向收缩。NO_3^-—N、PO_4^(3-)—P、SiO_3^(2-)—Si与盐度有显著或高度负相关关系,说明NO_3^-—N、PO_4^(3-)—P、SiO_3^(2-)—Si主要来自近岸淡水的输送。

Based on the data gained from two field investigations handled on Subei Shoal in May and June 2016,the structure and distribution characteristics of dissolved nutrients were analyzed.The results show that the main form of DIN(dissolved inorganic nitrogen,the sum of nitrite,nitrate and ammonia)was nitrate,and nitrite was the least,DON(dissolved organic nitrogen)was the main form of TDN(total dissolved nitrogen),and DOP(dissolved organic phosphorus)was under the detection limit.In terms of the ratio among N、P and Si,the growth of phytoplankton was constricted by phosphorus.There was a offshore decreasing trend in the spatial distribution of NO-3-N(nitrate)、PO 3-4-P(phosphate)and SiO 2-3-Si(silicate),but there was no obvious pattern in the spatial distribution of NO-2-N(nitrite)、NH+4-N(ammonia)and DON.Compared to May,the concentration of dissolved nutrients declined obviously,except NO 2-N;the region with high value of NO-3-N、PO 3-4-P and SiO 2-3-Si shrank inshore.There were significant or high negative correlations between salinity and NO-3-N、PO 3-4-P、SiO 2-3-Si,indicating that the main source of these three nutrients was terrigenous fresh water input.