近年渤海中部海域活性磷酸盐的时空变化特征

Recent Temporal and Spatial Variation in Active Phosphate Concentration in Seawater of the Central Bohai Sea

渤海封闭性强,水动力条件和自净能力较弱,其生态系统较为敏感和脆弱。2011年位于渤海中部的蓬莱19-3油田发生重大溢油事故,对渔业生态环境和渔业资源造成了严重影响。为了解和掌握该起溢油污染事故发生后渔业生态环境的变化状况,分别于2012-2014年在渤海中部海域进行了9个航次的生态环境跟踪调查。利用其中部分调查资料,作者对渤海中部活性磷酸盐的时空变化特征及其影响因素进行了分析探讨。结果显示,(1)2012-2014年春季和夏季渤海中部海域活性磷酸盐含量符合第二类海水水质标准要求,秋、冬季部分海域已受到活性磷酸盐的污染。(2)不同季节渤海中部海域活性磷酸盐的平面分布趋势各异,垂直分布也存在季节差异。春季和夏季活性磷酸盐呈现由表层至底层递减的趋势,秋季和冬季接近呈垂直分布均匀状态。(3)渤海中部海域活性磷酸盐平均含量季节变化明显,其含量顺序由高到低依次为冬季、秋季、春季、夏季,冬季明显高于夏季。2014年渤海中部海域活性磷酸盐含量低于2013年,呈逐年降低趋势。(4)渤海中部海域活性磷酸盐时空变化受到诸多因素的影响,营养盐的外源补充、内源再生和生物消耗是影响活性磷酸盐时空变化的最重要因素。

The Bohai Sea is a semi-closed gulf with weak hydrodynamic condition and self-purification capacity. Therefore its eco-system is more sensitive and fragile than open seas. A serious oil spill accident occurred in the Penglai 19-3 oil field located in the central Bohai Sea in 2011, which severely affected the marine ecological environment and fishery resources. To determine the aftermath in fishery ecological environment, nine surveys were carried out in the central Bohai Sea in 2012–2014. Based on part of the survey data, we analyzed the temporal and spatial variation in active phosphate and the corresponding factors in the central Bohai Sea. The results showed that the levels of active phosphate met thesecond class of sea water quality standard in spring and summer from 2012 to 2014, but the pollution caused by active phosphate was observed in part of the survey in autumn and winter; the horizontal and vertical distribution of active phosphate varied in different seasons, and in spring and summer the concentration of active phosphate gradually decreased along with the increase in depth, while in autumn and winter it was almost constant from the surface to the bottom; the seasonal mean concentration of active phosphate followed the order winter〉autumn〉spring〉summer, and it was obviously higher in winter than in summer, plus the mean concentration was lower in 2014 than in 2013; The distribution and variation of active phosphate in the central Bohai Sea was affected by many factors, and key ones included exogenous supplement, endogenous release of nutrients, and biological consumption.