东山湾海水中Fe(Ⅱ)和Fe(Ⅲ)相互转化围隔实验研究

Transformation of Fe (Ⅱ) and Fe (Ⅲ) in Enclosures of Dongshan Bay

根据2008年8月与11月在东山湾海域获得的调查资料对表层水中溶解态Fe(II)和Fe(III)含量、浮游植物叶绿素a、营养元素及其浓度等环境参数进行分析。结果表明,夏、秋季海水中Fe(II)浓度及其在总溶解铁中所占比例均与浮游植物叶绿素a呈正相关,其相关系数分别为0.7959、0.9219。现场围隔实验表明,海水中总溶解态Fe含量在24 h内有较大的变化,最大减少量达到17.4%。DS2站点海水中Fe(II)浓度及其在总溶解铁中所占比例随光照强度增加而增加。最高值与初始值相比较,叶绿素a较高的DS2站点海水中Fe(II)浓度增加较叶绿素a较低的DS5号站点高0.053μg/L。Fe(II)和Fe(III)加富实验研究了溶解态的Fe(II)和Fe(III)在海水中相互转化。高浓度的Fe(II)在海水中被氧化成Fe(III),海水中浮游植物也会引发光还原作用使Fe(III)还原成Fe(II)。

Based on the samples collected from Dongshan Bay during in August and November 2008 for the field observation,the concentrations of total dissolved iron,Fe（II）,Fe（III）,chlorophyll a,nutrients,and other parameters were determined and discussed in this paper.Both of the concentration of Fe（II） and the percentage of Fe（II） of total dissolved iron were positive correlation with chlorophyll a and the correlation coefficients were 0.7959 and 0.9219,respectively.According to the results from the mesocosm experiments,total dissolved iron was depressed 17.4% during 24 hours,while the concentration of Fe（II） and the percentage of Fe（II） of total dissolved iron were increased.The concentration of Fe（II） in seawater from DS2 where marine phytoplankton was abundant was more than that from DS5 which was lacking of phytoplankton.Enrichment experiments of Fe（II） and Fe（III） were set up to study the transformation between Fe（II） and Fe（III）.The results showed that Fe（II） was oxidized rapidly in seawater,and Fe（III） was reduced to Fe（II） by the light-induced photochemical activity of marine phytoplankton.