Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea
The faecal pellets egested by zooplankton are essential as they influence the vertical material flux in oceans. As mesozooplankton are dominant within the plankton community in the southern Okhotsk Sea during early summer, the vertical material flux via mesozooplankton is expected to be substantial....
Published in: | Deep Sea Research Part I: Oceanographic Research Papers |
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/86941 2023-05-15T17:52:37+02:00 Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea Kojima, Daiki Hamao, Yusuke Amei, Kanako Fukai, Yutaka Matsuno, Kohei Mitani, Yoko Yamaguchi, Atsushi http://hdl.handle.net/2115/86941 https://doi.org/10.1016/j.dsr.2022.103771 eng eng Elsevier http://hdl.handle.net/2115/86941 Deep Sea Research Part I Oceanographic Research Papers, 185: 103771 http://dx.doi.org/10.1016/j.dsr.2022.103771 Carbon flux Copepoda Coprophagy Faecal pellet Okhotsk Sea ZooScan 452 article fthokunivhus https://doi.org/10.1016/j.dsr.2022.103771 2022-11-18T01:07:06Z The faecal pellets egested by zooplankton are essential as they influence the vertical material flux in oceans. As mesozooplankton are dominant within the plankton community in the southern Okhotsk Sea during early summer, the vertical material flux via mesozooplankton is expected to be substantial. However, quantitative information on their faecal pellets is currently lacking. In this study, we evaluated the taxonomic accounts of the entire plankton community, including microplankton, mesozooplankton, and macrozooplankton, in the 0-1000 m water column. The ingestion and egestion rates of the zooplankton were also estimated. We used a fine-mesh (63 mu m) plankton net along with an imaging technique (with ZooScan) to quantify the amount of in-situ faecal pellets. Furthermore, on-board experiments were conducted to estimate the faecal pellet egestion by the dominant zooplankton species. Cosmopolitan diatom species were found to dominate the microplankton biomass, whereas the large-sized calanoid copepod Metridia okhotensis, which performs nocturnal ascent diel vertical migration, dominated the mesozooplankton biomass. Two euphausiid species with different body sizes, namely the small-sized Thysanoessa inermis and the large-sized Euphausia pacifica, were found to be dominant among the macrozooplankton. The highest density and mass of faecal pellets (1888 pellets m(-3), 2.96 mg C m(-3)) was observed in the 0-100 m layer during the daytime. Throughout the layer, the volumes of the faecal pellets peaked at 0.010-0.015 mm(3), which corresponded with the size of the pellets egested by M. okhotensis in the on-board laboratory experiments. The large-sized faecal pellets (> 0.2 mm(3)), which were inferred to be egested by euphausiids, were only observed during the night-time. Based on the on-board experiments, the faecal pellets egested by all the meso- and macrozooplankton species contained phytoplankton cells that possessed a fluo-rescent ability. Furthermore, cyanobacteria were the most common taxa (26-65% in number) ... Article in Journal/Newspaper okhotsk sea Thysanoessa inermis Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Okhotsk Deep Sea Research Part I: Oceanographic Research Papers 185 103771 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
Carbon flux Copepoda Coprophagy Faecal pellet Okhotsk Sea ZooScan 452 |
spellingShingle |
Carbon flux Copepoda Coprophagy Faecal pellet Okhotsk Sea ZooScan 452 Kojima, Daiki Hamao, Yusuke Amei, Kanako Fukai, Yutaka Matsuno, Kohei Mitani, Yoko Yamaguchi, Atsushi Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
topic_facet |
Carbon flux Copepoda Coprophagy Faecal pellet Okhotsk Sea ZooScan 452 |
description |
The faecal pellets egested by zooplankton are essential as they influence the vertical material flux in oceans. As mesozooplankton are dominant within the plankton community in the southern Okhotsk Sea during early summer, the vertical material flux via mesozooplankton is expected to be substantial. However, quantitative information on their faecal pellets is currently lacking. In this study, we evaluated the taxonomic accounts of the entire plankton community, including microplankton, mesozooplankton, and macrozooplankton, in the 0-1000 m water column. The ingestion and egestion rates of the zooplankton were also estimated. We used a fine-mesh (63 mu m) plankton net along with an imaging technique (with ZooScan) to quantify the amount of in-situ faecal pellets. Furthermore, on-board experiments were conducted to estimate the faecal pellet egestion by the dominant zooplankton species. Cosmopolitan diatom species were found to dominate the microplankton biomass, whereas the large-sized calanoid copepod Metridia okhotensis, which performs nocturnal ascent diel vertical migration, dominated the mesozooplankton biomass. Two euphausiid species with different body sizes, namely the small-sized Thysanoessa inermis and the large-sized Euphausia pacifica, were found to be dominant among the macrozooplankton. The highest density and mass of faecal pellets (1888 pellets m(-3), 2.96 mg C m(-3)) was observed in the 0-100 m layer during the daytime. Throughout the layer, the volumes of the faecal pellets peaked at 0.010-0.015 mm(3), which corresponded with the size of the pellets egested by M. okhotensis in the on-board laboratory experiments. The large-sized faecal pellets (> 0.2 mm(3)), which were inferred to be egested by euphausiids, were only observed during the night-time. Based on the on-board experiments, the faecal pellets egested by all the meso- and macrozooplankton species contained phytoplankton cells that possessed a fluo-rescent ability. Furthermore, cyanobacteria were the most common taxa (26-65% in number) ... |
format |
Article in Journal/Newspaper |
author |
Kojima, Daiki Hamao, Yusuke Amei, Kanako Fukai, Yutaka Matsuno, Kohei Mitani, Yoko Yamaguchi, Atsushi |
author_facet |
Kojima, Daiki Hamao, Yusuke Amei, Kanako Fukai, Yutaka Matsuno, Kohei Mitani, Yoko Yamaguchi, Atsushi |
author_sort |
Kojima, Daiki |
title |
Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
title_short |
Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
title_full |
Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
title_fullStr |
Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
title_full_unstemmed |
Vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern Okhotsk Sea |
title_sort |
vertical distribution, standing stocks, and taxonomic accounts of the entire plankton community, and the estimation of vertical material flux via faecal pellets in the southern okhotsk sea |
publisher |
Elsevier |
url |
http://hdl.handle.net/2115/86941 https://doi.org/10.1016/j.dsr.2022.103771 |
geographic |
Okhotsk |
geographic_facet |
Okhotsk |
genre |
okhotsk sea Thysanoessa inermis |
genre_facet |
okhotsk sea Thysanoessa inermis |
op_relation |
http://hdl.handle.net/2115/86941 Deep Sea Research Part I Oceanographic Research Papers, 185: 103771 http://dx.doi.org/10.1016/j.dsr.2022.103771 |
op_doi |
https://doi.org/10.1016/j.dsr.2022.103771 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
185 |
container_start_page |
103771 |
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1766160293057003520 |