夏季南海西部中尺度物理过程对营养盐和叶绿素a分布特征的影响

Mesoscale physical processes on the effects of distribution of nutrients and chlorophyll ain the western South China Sea in summer

通过对2014年8月31日—9月26日国家自然科学基金委南海西部综合航次的调查结果分析,发现在中南半岛沿岸海域存在具有低温高盐的冷涡和位于其东南部海域具有高温低盐的暖涡。相对于暖涡和其他海域,冷涡水团含有更高的营养盐,并在50m、75m和100m层增加明显,DIP分别高0.21μmol/L、0.39μmol/L和0.23μmol/L,DIN分别高4.94μmol/L、7.56μmol/L和3.76μmol/L,DSi分别高2.55μmol/L、5.25μmol/L和3.46μmol/L,说明冷涡对提高初级生产力具有明显的营养优势条件和巨大潜力;叶绿素a最大值均出现在50m层,其中以海南岛近岸海域最大,冷涡在25m层提高初级生产力明显,主要是受营养盐影响显著;而在75m、100m层可能受到冷涡带来的低温环境而导致叶绿素a含量不高。

Samples for seawater nutrients and chlorophyll awere collected in the western South China Sea from 31 August to 26 September,2014.Results show that coast of IndoChina have cold-core eddy with low temperature,high salinity and warm-core eddy with high temperature,low salinity which is located in the lower right relative to cold-core eddy.Relative to warm-core eddy and other areas,nutrients of cold-core eddy have higher concentration,50 m,75mand 100 mlayer of which is increased remarkably.DIP higher by 0.21μmol/L,0.39μmol/L and 0.23μmol/L respectively,DIN higher by 4.94μmol/L,7.56μmol/L and 3.76μmol/L respectively,and DSi higher by2.55μmol/L,5.25μmol/L and 3.46μmol/L respectively.It indicates cold-core eddy on improving primary production with significant nutritional advantages and huge potential.DCM layer appear in 50 mlayer,maximum value of which is located in coast of Hainan island.Under the influence of nutrients,cold-core eddy increases primary productivity significantly in 25 mlayer,while value of Chl ais not high in 75 m,100mlayer,which may be caused by low temperature with cold-core eddy.