夏季西南印度洋叶绿素a分布特征  

The distribution of chlorophyll a in the Southwestern Indian Ocean in summer

作　　者：洪丽莎[1,2] 王春生[1,2] 周亚东[1,2] 林钟扬[1,2] 王小谷[1,2] 宋迅殊[1,3] 

机构地区：[1]国家海洋局第二海洋研究所,杭州310012 [2]国家海洋局海洋生态系统与生物地球化学重点实验室,杭州310012 [3]卫星海洋环境动力学国家重点实验室,杭州310012

出　　处：《生态学报》2012年第14期4525-4534,共10页Acta Ecologica Sinica

基　　金：中国大洋矿产资源研究开发协会专项基金(DY125-13-E-01)

摘　　要：分析了2011年1月西南印度洋叶绿素a的分布特征及其粒级结构,并结合水动力学环境和营养盐数据探讨了其主要影响因素。结果表明,西南印度洋副热带涡流(IOSG)区表层叶绿素a浓度较低,不超过0.07 mg/m3,次表层叶绿素a浓度最大值所在水层较深,超过100 m;副热带聚集区(SCZ)表层叶绿素a浓度较高(0.164—0.247 mg/m3),次表层叶绿素a浓度最大值出现在50—70 m层。硝酸盐是该海区浮游植物生长的主要限制因素。微微型(pico)粒级的浮游植物占绝对优势,所有站位其对总叶绿素a的平均贡献率为71.1%,微型(nano)粒级次之(24.2%),小型(net)粒级所占比例最小(4.7%),其中IOSG区pico粒级对总叶绿素a的平均贡献率为77.9%,SCZ的pico粒级对总叶绿素a的平均贡献率为66.7%。IOSG区和SCZ海区之间水动力学环境的不同,可能导致了这两个海区叶绿素a的分布特征及粒级结构的较大差异。An investigation of the distribution and size composition of chlorophyll a concentration was carried out in the Southwestern Indian Ocean（47—70°E,25—40°S） in January 2011,and factors that might affect the distribution and size composition were discussed.Fluorometric method was used to obtain total and size-fractioned chlorophyll a concentrations.The survey was carried out during the austral summer,and there were 6 stations altogether,two of which located in the region of the south Indian Ocean Subtropical Gyre（IOSG） and the other four located in the subtropical convergence zone（SCZ）.Water samples were collected from 13 layers in 0—200m column of each station and the vertical profiles of chlorophyll a,nutrients（NO-3 、PO3-4 and SiO2-3）,temperature and salinity were obtained.The objective of this study was to investigate the spatial distribution and size fraction of chlorophyll a concentration and to relate them to environmental factors.The results showed that the surface chlorophyll a concentration was low and did not exceed 0.07mg/m3,and the depth of the subsurface chlorophyll a maximum was deep,at approximately 100m and sometimes reaching as deep as 150m in the region of IOSG;However,in the SCZ,the surface chlorophyll a concentration was higher（0.164—0.247 mg/m3）,and the subsurface chlorophyll a maximum layer occurred between 50—70m.In the region of IOSG,phytoplankton growth is limited by nutrients supply,while the frontal system formed by the Agulhas Return Current（ARC） and the Subtropical Convergence（STC） is a region of intense mesoscale activity presenting enhanced levels of biological production and chlorophyll a concentration.Based on the discussion of the factors affecting the distribution of phytoplankton,it appeared that NO-3 was the main factor that limited the growth of phytoplankton in the southwestern Indian Ocean,and PO3-4 could be the main limiting factor in some areas.Size-fractioned chlorophyll a concentration clearly showed that the study area was a typic

关 键 词：西南印度洋 叶绿素A 粒级结构 

分 类 号：Q948.8[生物学—植物学]