香港海域叶绿素-a浓度的时空分布规律

选取香港海域7个水环境控制区在1988 ~ 1999年期间每月或每半月定位连续取样的37个水质测站,每个测站选用17个水质参数,研究香港海域海岸带水体叶绿素-a浓度及其相关因子的时空分布规律。对37个测站17个参数作聚类分析,结果表明,香港海域东部由半封闭海湾组成的水域控制区,其赤潮发生频率较高;西部水域属于河口环境。多变量分析结果表明,BOD5对叶绿素-a浓度普遍存在显著性影响,氮和光照条件在东部海域对叶绿素-a浓度的影响比西部海域更显著,而磷以及包括盐度、温度、溶解氧和pH在内的海洋物理化学条件在西部海域有更显著的影响。在整个香港海域,年内平均最高叶绿素-a浓度主要出现在冬末春初和夏末秋初,东部海域的年平均叶绿素-a浓度一般高于西部海域。香港海域的叶绿素-a浓度普遍存在一个8~10年的周期性变化规律。||Seven Water Control Zones in Hong Kong’s coastal waters with sampling data of 17 parameters collected at 37 monitoring stations from 1988 to 1999 were selected to analyze the spatio-temporal variations of chlorophyll-a concentration. The results suggest that frequent red tides occurred in eastern Hong Kong’s coastal waters, and less red tides occurred in an estuarine environment in the west. In all coastal waters, the organic contents indicator, BOD 5 , was a common significant influential factor of the chlorophyll-a level. Nitrogen and light penetration condition related to turbility, total volatile solids and suspended solids had greater influence on the cholophyll-a level in the east than in the west, while phosphorus and oceanographic condition associated with salinity, temperature, dissolved oxygen and pH was more important in west than in east. Generally, there was a higher average chlorophyll-a level in the late winter and early spring, and late summer and early autumn in a year. The chlorophyll-a level was higher in the east than in the west among all seasons in general. The chlorophyll-a concentration has a fluctuation period of 8-10 years generally in the whole region.