The temporal and spatial distribution characteristics and affecting factors of dissolved oxygen in the offshore water of Tianjin in recent 15 years were studied,based on the dissolved ox-ygen data.The results showed that the inter-annual variation of the annual averages of the dis-solved oxygen content in Tianjin coastal regions was small.The maximum and minimum annual average of the dissolved oxygen was respectively found in 2012 and 2008,and with time goes on, the annual change of the dissolved oxygen was firstly decreased and then slowly increased.The dissolved oxygen content varied with seasons,and a descending order that winter,spring,autumn and summer was found in surface seawaters,as well as in bottom seawaters.From January on-wards,the variations of the dissolved oxygen content were in sine forms,and the maximum and minimum was respectively found in January and September.As the water depth increases,the dis-solved oxygen content showed a decreasing trend as the result of the loss of good water-air ex-change functions,adequate illuminations and effective plants photosynthesis in surface seawaters. Statistical analysis showed that factors including the temperature,salinity and pH were related to the dissolved oxygen content,and indicating that these factors may determine the dissolved oxygen content of coastal waters in Tianjin.%文章基于2001—2015年15年的长时间序列溶解氧含量和相关理化因子的多源数据,研究天津近岸海域溶解氧含量的分布特征和影响因素,结果表明:溶解氧含量年均值的变化幅度较小且分布稳定,在2008年出现较小值,2008年后有略微升高的趋势,在2012年出现较大值;表层平均值和底层平均值均存在由大到小依次为冬季、春季、秋季、夏季的规律;月均值呈正弦变化趋势,最高值出现在1月,最低值出现在9月,6-9月均较低;溶解氧含量随深度的增加有降低的趋势,这主要是由于表层海气交换充分且阳光充足,植物的光合作用占优势;海水温度、盐度和pH值都对溶解氧含量产生重要影响,均存在相关关系.
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