钦州湾近20a来水环境指标的变化趋势 Ⅵ溶解氧的含量变化及其在生态环境可持续发展中的作用

Change trend of water environmental index in Qinzhou Bay last 20 years Ⅵ variation and effect of DO content on sustainable development of ecological environment

通过对钦州湾1983～2003年10个航次调查资料的分析，探讨了该湾溶解氧的含量变化及其在生态环境可持续发展中的作用。结果表明：20a来该湾水体中的DO含量变化并不大，所有航次均在一类海水标准范围内，以冬季最高、春季次之、夏秋季较低的特征出现；O2％的变化与DO相一致。但由于浮游植物在海湾生态环境的演变过程中扮演了正、反两方面的角色，从而使DO与环境因子之间的关系趋于复杂，作为温盐函数的DO，与水温之间却多以显著正相关出现，与盐度则多以显著负相关出现，与pH、COD、浮游植物（或chl．a）和N、P、Si的相关性，却体现了时代变迁的特征；02％的相关变化与DO不尽一致。但总的说来，浮游植物的增氧作用在海湾生态环境可持续发展的进程中起到了主导影响作用。

Based on the data obtained from 10 cruises in Qinhou Bay 1983 - 2003, the variation and effect of DO content on the sustainable development of the ecological environment in the bay were studied. The results showed that there was not significant change of DO content in water of the bay. All of the cruises showed that DO content was within the range of the first class to the marine water quality standard. The highest was in winter, a little lower in spring, and the lowest in summer and autumn, and it was consistent with the variation of O2%. Due to the positive and negative effects of phytoplankton on the environmental change, the relation between DO and environmental factors is complicated. The temperature - salinity function of DO was a strong positive correlation with water temperature and a strong negative correlation with salinity, but the correlations with pH, COD, phytoplankton （or chl. a） , N, P, and Si showed an evolution with the age. On the other hand, the changes of O2 % are different with DO. As a whole, the enrichment oxygen effect of phytoplankton has played a leading role in the sustainable development of ecological environment in the bay.