热带西太平洋部分海域海水的化学状况分析

Chemical Characteristics of Seawater in the Partial Regions of the Tropic West-pacific

本文对１９９２年１１月棉兰老岛东南海域、伊里安岛北部海域上层水及４０°Ｓ１５６°Ｅ定点长达４个月的ｐＨ、Ｅｈ、∑Ｓ（－Ⅱ）调查分析，研究了上述海域的海水化学状况，结果表明，１９９２年１１月，在上层水中（０～１５０ｍ），棉兰老岛东南海域海水的碱性较弱、氧化性较强，伊里安岛北部海域海水碱性较强，还原性较强，４°Ｓ１５６°Ｅ的上层水界于二者之间；在４°Ｓ１５６°Ｅ海水中，５０ｍ左右是一层碱性最强的海水，其ｐＨ≥８．３０，３００ｍ以下ｐＨ则在７．８０～７．９０之间，碱性较弱，５０～２００ｍ是Ｅｈ、∑Ｓ（－Ⅱ）的跃层区，Ｅｈ变为低值，∑Ｓ（－Ⅱ）变为高值，该层海水的还原性最强；在其光层内，ｐＨ一般在中午１２：００出现最大值，凌晨４：００出现最低值，下午４：００一般出现Ｅｈ最低值，∑Ｓ（－Ⅱ）的最高值，这时海水的还原性最强；在其光层内，浮游植物的光合作用是控制海水碱度的主要因素，海气界面的氧交换是控制海水氧化还原的重要因素，温度是决定海水中∑Ｓ（－Ⅱ）产生的重要因素之一。

The chemical characteristics of seawater in the partial regions of the tropic westpacific were studied through the observations of pH,Eh and ∑S (-Ⅱ)in Nov,1992.The results show that lower alkalinity and stronger oxidation in the upper water(0～150m)appeared in the southeast off Mindanao Island,and higher alkalinity and stronger reduction appeared in the north off New Guinea Island.Alkalinity was the highest and.pH was more than 8.30 at 50m layer.pH values were from 7.80 to 7.90 below 300m and alkalinity were low at 4°S156°E. At 50～200m layer Eh and ∑S (-Ⅱ)were in the sharp-chine and the lowest Eh and the highest ∑S (-Ⅱ) appeared in it.In the euphotic,the maximum of pH apeared at l2 o'clock and the minimum of pH at 4 o'colck a.m.,and the lowest Eh and the highest ∑S(-Ⅱ)appeared at 4 o'clock p.m. while the reduction of the seawater is the strongest day and night.Photosynthesis of phytoplankton is the main factor that controlls alkalinity of the seawater.Oxygen excharged through the sea-air interface mainly controlls redox the charactensitic of the seawater. The temperature of the seawater is one of the importtant factors of the production of ∑S (-Ⅱ).