High-West and Low-East Distribution Patterns of Chlorophyll a, Primary Productivity and Diatoms in the Subarctic North Pacific Surface Waters, Midwinter 1996
High-West and Low-East Distribution Patterns of Chlorophyll a, Primary Productivity and Diatoms in the Subarctic North Pacific Surface Waters, Midwinter 1996
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1996年仲冬亚北极北太平洋表层水中叶绿素a、初级生产力和硅藻的高西低东分布模式
DOI：
10.1023/a:1007835306413
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发表时间：
1999
影响因子：
2.3
通讯作者：
H. Asami
中科院分区：
文献类型：
--
作者：
A. Shiomoto;H. Asami
1996年1月，我们测定了北太平洋亚北极表层叶绿素a （Chla）浓度、初级生产力、硅藻细胞密度和种类组成以及微型浮游动物的数量。在巡航期间，还测量了从150米到水面的垂直拖曳所获得的桡足类动物的湿重。Chla浓度和初级生产力在180°西部亚北极北太平洋（WSNP）地区高于180°东部亚北极北太平洋（ESNP）地区。对总硅藻细胞密度、海藻属和齿藻属观察到相同的结果。海藻细胞密度与Chla浓度和初级生产力之间存在显著的线性关系，表明海藻对Chla浓度和初级生产力的高wsnp和低esnp分布模式有贡献。此外，裸纤毛虫的丰度在WSNP中比在ESNP中低，而桡足类生物量则呈现相反的趋势。海硅藻细胞密度与裸纤毛虫数、裸纤毛虫数与桡足类湿重呈显著负Spearman秩相关。这些结果表明，桡足类食草动物通过捕食裸纤毛虫间接控制海assiassira细胞密度。我们认为，高桡足类生物量是控制高WSNP和低esnp海硅藻丰度的一个因素，从而控制Chla浓度和初级生产力模式。
We have determined chlorophyll a (Chla) concentration, primary productivity, cell density and species composition of diatoms, and the number of microzooplankton at the surface in the subarctic North Pacific in January 1996. The wet weight of copepods obtained by vertical tows from 150 m to the surface was also measured during the cruise. Chla concentration and primary productivity tended to be higher in the region west of 180°, the western subarctic North Pacific (WSNP), than east of 180°, the eastern subarctic North Pacific (ESNP). The same results were observed for the total diatom cell densities and for the genera Thalassiosira and Denticulopsis. Significant linear relationships were observed between the Thalassiosira cell density and Chla concentration and primary productivity, indicating that Thalassiosira contributes to the high-WSNP and low-ESNP distribution patterns of Chla concentration and primary productivity. Moreover, naked ciliate abundance tended to be lower in the WSNP than in the ESNP, whereas copepod biomass showed an inverse trend. Significantly negative Spearman rank correlations were found between the Thalassiosira cell density and the number of naked ciliates and between the number of naked ciliates and the wet weight of copepods. These results indicate that copepod grazing indirectly controls Thalassiosira cell density via predation on the naked ciliates. We conclude that the high copepod biomass in the WSNP is a factor controlling the high-WSNP and low-ESNP Thalassiosira abundance and hence Chla concentration and primary productivity patterns.