大鹏湾中叶绿素-a的多年调查结果及其与环境因子的灰关联分析

依据1998-2009年145个航次的调查资料，简要描述和分析大鹏湾海水中叶绿素-a含量的空间分布和时间变化，并对其与各环境因子之间的灰关联进行分析。结果表明大鹏湾海水中的叶绿素-a含量夏、秋季较高，而冬、春季较低，且表层高于底层，平均为4．6μg-L^-1；由于受到香港和深圳陆源排放的影响，终年吐露港和沙头附近海域的叶绿素-a含量明显高于其他区域。lla（1999-2009）调查期间，香港海区叶绿素-a含量各航次均值的年际变化略呈下降趋势，表明大鹏湾海水的生态环境质量有所改善。灰关联分析结果表明各因子对叶绿素-a含量影响大小的排序为：亚硝酸盐≥硝酸盐≥5d生化需氧量≥磷酸盐≥酸碱度≥氨≥可溶性总氮≥盐度兰可溶性总磷≥溶解氧≥可溶性硅兰温度。

Analysis of multi-year measurements of chlorophyll-a and its grey incidences to environmental factors in the Mirs Bay

Based on the data obtained from 145 cruises from 1998 to 2009, the spatial distribution and temporal variation of the chlorophyll-a concentration and its grey incidences with various environmental factors in the seawater of Mirs Bay were briefly presented and analyzed. It was shown that the chlorophyll-a concentration, with an average of 4.6 μg.L^-1, was generally higher in summer and autumn than winter and spring and higher in the surface than the bottom. It was perennially higher in the Tolo Harbourand the Sha Tau Kok Sea zones than the other zones of Mirs Bay due to the impact of seaward discharges from the cities of Hongkong and Shen Zhen. During the investigated 11 years （from 1999 to 2009）, the interarmual variation of the chlorophyll-a concentration averaged in each cruise from the Hongkong zone witnessed a decreasing trend, indicating an improvement of the ecological environmental quality for the seawater in the bay. The analytic result of the grey incidence showed that the incident orderof impacts of the various environmental factors on the chlorophyll-a was nitrite ≥ nitrate ≥ 5 days biochemical oxygen demand≥ phosphate ≥ pH≥ ammonia ≥ dissolvable total nitrogen ≥ salinity ≥ dissolvable total phosphorus ≥ dissolved oxygen ≥ dissolvable silica ≥ temperature.