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Community and trophic structures of pelagic copepods down to greater depths in the western subarctic Pacific (WEST-COSMIC)

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Title: Community and trophic structures of pelagic copepods down to greater depths in the western subarctic Pacific (WEST-COSMIC)
Authors: Yamaguchi, Atsushi Browse this author →KAKEN DB
Watanabe, Yuji Browse this author
Ishida, Hiroshi Browse this author
Harimoto, Takashi Browse this author
Furusawa, Kazushi Browse this author
Suzuki, Shinya Browse this author
Ishizaka, Joji Browse this author
Ikeda, Tsutomu Browse this author →KAKEN DB
Takahashi, Masayuki Mac Browse this author
Keywords: copepods
community structure
species diversity
carbon cycle
carbon flux
Issue Date: 2002
Publisher: Elsevier
Journal Title: Deep Sea Research Part I: Oceanographic Research Papers
Volume: 49
Issue: 6
Start Page: 1007
End Page: 1025
Publisher DOI: 10.1016/S0967-0637(02)00008-0
Abstract: As part of the research program “WEST-COSMIC (Western Pacific Environment Study on CO2 Ocean Sequestration for Mitigation of Climate Change)”, vertical distribution and community structure of copepods were studied at Station Knot (44˚N, 155˚E) down to 4000 m depth in the western subarctic Pacific. Vertical carbon flux mediated by copepod communities was also estimated. Both abundance and biomass of copepods were greatest in the near surface layer and decreased with increasing depth. Decrease of abundance with depth was best fitted to power regression model, while that of biomass was best described by an exponential regression model. Copepod carcasses occurred throughout the layer, and carcasses/living specimens ratios were greatest in the deepest layer (the ratio was 9.3 at 3000-4000 m depth). A total of 98 calanoid copepod species belonging to 38 genera and 15 families occurred in the 0-4000 m water column (Cyclopoida, Harpacticoida and Poecilostomatoida were not identified to species). The number of genera and species showed bimodal vertical distributions with peaks at 500-1000, and at 2000-3000 m both during day and night. Based on the species similarity indices, copepod community could be classified into epipelagic, mesopelagic and bathypelagic communities. Based on the feeding pattern, copepods were divided into four types: suspension feeders, suspension feeders in diapause, detritivores and carnivores. In terms of abundance, the most dominant group was suspension feeders (mainly the cyclopoid genus Oithona) in the epipelagic zone, while detritivores (mainly Poecilostomatoida genus Oncaea) were dominant in the meso- and bathypelagic zones. In terms of biomass, suspension feeders in diapause (calanoid genera Neocalanus and Eucalanus) were the major component (ca. 70%), especially at 200-2000 m depth. Comparison of vertical flux of particulate carbon with estimated copepod ingestion/egestion rates suggests that the suspension feeding copepods receive sufficient food. For detritivorous copepods, copepod carcasses, a possible food source, are not abundant enough, so other food sources need to be considered. As a food source for carnivorous copepods, the abundance of suspension feeding and detritivorous copepods appears to be high enough to meet their demand. Our calculation showed that an average of 32% of the particulate carbon flux is consumed by copepods in the 0-4000 m water column.
Type: article (author version)
Appears in Collections:水産科学院・水産科学研究院 (Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 山口 篤

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