泉州湾春、夏季表层溶解氧分布特征及其影响因素分析

Distribution of Dissolved Oxygen in the Surface Water and Its Influencial Factors in Quanzhou Bay During Spring and Summer

水体中的溶解氧(dissolved oxygen,DO)分布受控于复杂的生物地球化学过程,对区域生态环境保护和修复有重要意义.泉州湾表层水体DO的分析结果表明,春、夏季DO的质量浓度分别为6.37~8.24mg/L和2.76~7.62mg/L,两季差异主要是由于水温和DO消耗强度的变化.受入海径流和潮汐的影响,DO呈现从湾内向湾口增加的趋势,其中春季DO总体变化较小,在西南部海域的变化幅度比海湾中部至湾口更明显,而夏季反之.泉州湾的表观耗氧量(apparent oxygen utilization,AOU)与化学需氧量(chemical oxygen demand,COD)呈显著正相关,与盐度和pH均呈显著负相关,与营养盐的相关性在各潮期有异.总体而言,AOU分布在春、夏季均受有机物降解的强烈影响;夏季浮游生物生长旺盛,其耗氧过程对AOU分布的影响大于春季;春季浮游生物活动较弱,水动力条件对AOU的影响大于夏季.

Distribution of dissolved oxygen（DO）in water,which is influenced by complicated geochemical processes,plays an important role in ecological environment protection and restoration.We analyzed the DO concentrations in the surface water of Quanzhou Bay during spring and summer.The results showed that DO concentrations were 6.37-8.24 mg/L and 2.76-7.62 mg/L during spring and summer,respectively,and the seasonal difference was attributed to the differences of water temperature and oxygen consumption.DO concentrations increased from the inner bay to the bay mouth,and varied more significantly during spring than summer.Furthermore,DO concentrations varied more obviously in the southwestern waters than in the central of bay during spring,while varied in an opposite way during summer,which was mainly due to the effects of runoffs and tide.Apparent oxygen utilization（AOU）concentrations were significantly positively correlated with chemical oxygen demand（COD）and negatively correlated with salinity and pH,and the correlations between AOU and nutrients were different during various tidal periods.Generally,AOU distributions in Quanzhou Bay are influenced by organic matter degradation,plankton activities and mixture of runoffs and tide.The effects of plankton activities on AOU are greater during summer than spring,and the influences of runoffs and tide are stronger during spring than summer.