Short-term variation in copepod community and physical environment in the waters adjacent to the Kuroshio Current
Short-term variation in copepod community and physical environment in the waters adjacent to the Kuroshio Current
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DOI：
10.1007/s10872-017-0420-6
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发表时间：
2017-04
影响因子：
2.3
通讯作者：
S. Sogawa;Takashi Kidachi;M. Nagayama;T. Ichikawa;K. Hidaka;T. Ono;Y. Shimizu
中科院分区：
文献类型：
--
作者：
S. Sogawa;Takashi Kidachi;M. Nagayama;T. Ichikawa;K. Hidaka;T. Ono;Y. Shimizu
对日本伊豆群岛东北部至房总半岛浮游动物群落和海洋物理环境的短期变化进行了连续调查。高桡足类丰度和小隆起的表层和盐度最低层的次表层观察到的北侧海岸锋在最西端的样带，向南移动的黑潮离开房总半岛。因此，盐度最低层可能是形成上升流和锋面的关键因素，导致了伊豆群岛东北部沿海桡足类的大量存在。哲水蚤桡足类的群落结构分析显示，沿海和近海（黑潮）组合之间的中间带组合。在中间带，桡足类丰度极低，Ctenocalanus vanus占优势（近37%），表明Ctenocalanus对环境的耐受性较强。随着黑潮离开房总半岛，沿岸组合向同一方向扩展，伊豆群岛东北部外海的中间带组合消失。中华哲水蚤的最大种群出现在沿着伊豆群岛东北部的两条西部样带（>1000 m深度），推测是从相模湾向西南方向迁移，并在桡足类CIII至CV期生长。中华哲水蚤幼虫是除小拟哲水蚤外的重要饵料，在对桡足类不利的条件下，瓦氏C. vanus为优势种。
A continuous survey examined short-term variations in the zooplankton community and physical ocean environment from the northeastern Izu Islands to Boso Peninsula in Japan. High copepod abundance and small upwellings in the surface layer and salinity minimum layer in the subsurface were observed on the north side of coastal fronts in the westernmost transect, moving southward as the Kuroshio Current left the Boso Peninsula. Thus, the salinity minimum layer might be a key factor forming upwelling and the fronts, leading to large abundance of coastal copepods off the northeastern Izu Islands. A community structure analysis of calanoid copepods revealed an intermediate belt assemblage between coastal and offshore (Kuroshio) assemblages. Copepod abundance was remarkably low andCtenocalanus vanusdominated (nearly 37%) in the intermediate belt zone, indicating thatC. vanushas a relatively high tolerance to adverse environments for calanoid copepods. As the Kuroshio Current left the Boso Peninsula, the coastal assemblage expanded in the same direction, and the intermediate belt assemblage off the northeastern Izu Islands disappeared. The largest population ofCalanus sinicuswas found along the two western transects off the northeastern Izu Islands (>1000 m depth), which was assumed to be transported from Sagami Bay and advanced southwestward while growing from copepodite stages CIII to CV. Larvae ofC. sinicuswould be an important food for fish larvae in addition toParacalanus parvuss.l., the numerically dominant species in the coastal assemblage, andC. vanusunder the adverse conditions for coastal copepods.