Copepod Grazing Influences Diatom Aggregation and Particle Dynamics
In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggr...
Published in: | Frontiers in Marine Science |
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Language: | English |
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2019
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Online Access: | https://archimer.ifremer.fr/doc/00594/70605/68799.pdf https://archimer.ifremer.fr/doc/00594/70605/68800.mp4 https://archimer.ifremer.fr/doc/00594/70605/68801.mp4 https://archimer.ifremer.fr/doc/00594/70605/68802.mp4 https://doi.org/10.3389/fmars.2019.00751 https://archimer.ifremer.fr/doc/00594/70605/ |
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ftarchimer:oai:archimer.ifremer.fr:70605 2023-05-15T15:48:07+02:00 Copepod Grazing Influences Diatom Aggregation and Particle Dynamics Toullec, Jordan Vincent, Dorothée Frohn, Laura Miner, Philippe Le Goff, Manon Devesa, Jérémy Moriceau, Brivaela 2019-12 application/pdf https://archimer.ifremer.fr/doc/00594/70605/68799.pdf https://archimer.ifremer.fr/doc/00594/70605/68800.mp4 https://archimer.ifremer.fr/doc/00594/70605/68801.mp4 https://archimer.ifremer.fr/doc/00594/70605/68802.mp4 https://doi.org/10.3389/fmars.2019.00751 https://archimer.ifremer.fr/doc/00594/70605/ eng eng Frontiers Media SA https://archimer.ifremer.fr/doc/00594/70605/68799.pdf https://archimer.ifremer.fr/doc/00594/70605/68800.mp4 https://archimer.ifremer.fr/doc/00594/70605/68801.mp4 https://archimer.ifremer.fr/doc/00594/70605/68802.mp4 doi:10.3389/fmars.2019.00751 https://archimer.ifremer.fr/doc/00594/70605/ info:eu-repo/semantics/openAccess restricted use Frontiers In Marine Science (2296-7745) (Frontiers Media SA), 2019-12 , Vol. 6 , N. 751 , P. 22p. diatom aggregate grazing experiment copepod sinking velocity particle dynamics text Publication info:eu-repo/semantics/article 2019 ftarchimer https://doi.org/10.3389/fmars.2019.00751 2021-09-23T20:33:59Z In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggregates into small pieces through swimming activity or direct ingestion. Freely suspended cells, artificial monospecific aggregates from two different diatom species (Chaetoceros neogracile and Skeletonema marinoi) and natural aggregates of Melosira sp. were independently incubated with five different copepod species (Acartia clausi, Temora longicornis, Calanus helgolandicus, Euterpina acutifrons, and Calanus hyperboreus). During the grazing experiments initiated with free diatoms, E. acutifrons feeding activity evidenced by ingestion rates of 157 ± 155 ng Chl a ind–1 d–1, induced a significant increase of S. marinoi aggregation. Transparent exopolymeric particles (TEP) production was only slightly boosted by the presence of grazers and turbulences created by swimming may be the main trigger of the aggregation processes. All copepods studied were able to graze on aggregates and quantitative estimates led to chlorophyll a ingestion rates (expressed in Chla a equivalent, i.e., the sum of chlorophyll a and pheopigments in their guts) ranging from 4 to 23 ng Chl aeq ind–1 d–1. The relation between equivalent spherical diameters (ESDs) and sinking velocities of the aggregates did not significantly change after grazing, suggesting that copepod grazing did not affect aggregate density as also shown by Si:C and C:N ratios. Three main trends in particle dynamics could be identified and further linked to the copepod feeding behavior and the size ratio between prey and predators: (1) Fragmentation of S. marinoi aggregates by the cruise feeder T. longicornis and of Melosira sp. aggregates by C. hyperboreus at prey to predator size ratios larger than 15; (2) no change of particle dynamics in the presence of the detritic cruise feeder E. acutifrons; and finally (3) re-aggregation of C. neogracile and S. marinoi aggregates when the two filter feeders A. clausi and C. helgolandicus were grazing on aggregate at prey to predator size ratios lower than 10. Aggregation of freely suspended cells or small aggregates was facilitated by turbulence resulting from active swimming of small copepods. However, stronger turbulence created by larger cruise feeders copepods prevent aggregate formation and even made them vulnerable to breakage. Article in Journal/Newspaper Calanus hyperboreus Copepods Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Frontiers in Marine Science 6 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
diatom aggregate grazing experiment copepod sinking velocity particle dynamics |
spellingShingle |
diatom aggregate grazing experiment copepod sinking velocity particle dynamics Toullec, Jordan Vincent, Dorothée Frohn, Laura Miner, Philippe Le Goff, Manon Devesa, Jérémy Moriceau, Brivaela Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
topic_facet |
diatom aggregate grazing experiment copepod sinking velocity particle dynamics |
description |
In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggregates into small pieces through swimming activity or direct ingestion. Freely suspended cells, artificial monospecific aggregates from two different diatom species (Chaetoceros neogracile and Skeletonema marinoi) and natural aggregates of Melosira sp. were independently incubated with five different copepod species (Acartia clausi, Temora longicornis, Calanus helgolandicus, Euterpina acutifrons, and Calanus hyperboreus). During the grazing experiments initiated with free diatoms, E. acutifrons feeding activity evidenced by ingestion rates of 157 ± 155 ng Chl a ind–1 d–1, induced a significant increase of S. marinoi aggregation. Transparent exopolymeric particles (TEP) production was only slightly boosted by the presence of grazers and turbulences created by swimming may be the main trigger of the aggregation processes. All copepods studied were able to graze on aggregates and quantitative estimates led to chlorophyll a ingestion rates (expressed in Chla a equivalent, i.e., the sum of chlorophyll a and pheopigments in their guts) ranging from 4 to 23 ng Chl aeq ind–1 d–1. The relation between equivalent spherical diameters (ESDs) and sinking velocities of the aggregates did not significantly change after grazing, suggesting that copepod grazing did not affect aggregate density as also shown by Si:C and C:N ratios. Three main trends in particle dynamics could be identified and further linked to the copepod feeding behavior and the size ratio between prey and predators: (1) Fragmentation of S. marinoi aggregates by the cruise feeder T. longicornis and of Melosira sp. aggregates by C. hyperboreus at prey to predator size ratios larger than 15; (2) no change of particle dynamics in the presence of the detritic cruise feeder E. acutifrons; and finally (3) re-aggregation of C. neogracile and S. marinoi aggregates when the two filter feeders A. clausi and C. helgolandicus were grazing on aggregate at prey to predator size ratios lower than 10. Aggregation of freely suspended cells or small aggregates was facilitated by turbulence resulting from active swimming of small copepods. However, stronger turbulence created by larger cruise feeders copepods prevent aggregate formation and even made them vulnerable to breakage. |
format |
Article in Journal/Newspaper |
author |
Toullec, Jordan Vincent, Dorothée Frohn, Laura Miner, Philippe Le Goff, Manon Devesa, Jérémy Moriceau, Brivaela |
author_facet |
Toullec, Jordan Vincent, Dorothée Frohn, Laura Miner, Philippe Le Goff, Manon Devesa, Jérémy Moriceau, Brivaela |
author_sort |
Toullec, Jordan |
title |
Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
title_short |
Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
title_full |
Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
title_fullStr |
Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
title_full_unstemmed |
Copepod Grazing Influences Diatom Aggregation and Particle Dynamics |
title_sort |
copepod grazing influences diatom aggregation and particle dynamics |
publisher |
Frontiers Media SA |
publishDate |
2019 |
url |
https://archimer.ifremer.fr/doc/00594/70605/68799.pdf https://archimer.ifremer.fr/doc/00594/70605/68800.mp4 https://archimer.ifremer.fr/doc/00594/70605/68801.mp4 https://archimer.ifremer.fr/doc/00594/70605/68802.mp4 https://doi.org/10.3389/fmars.2019.00751 https://archimer.ifremer.fr/doc/00594/70605/ |
genre |
Calanus hyperboreus Copepods |
genre_facet |
Calanus hyperboreus Copepods |
op_source |
Frontiers In Marine Science (2296-7745) (Frontiers Media SA), 2019-12 , Vol. 6 , N. 751 , P. 22p. |
op_relation |
https://archimer.ifremer.fr/doc/00594/70605/68799.pdf https://archimer.ifremer.fr/doc/00594/70605/68800.mp4 https://archimer.ifremer.fr/doc/00594/70605/68801.mp4 https://archimer.ifremer.fr/doc/00594/70605/68802.mp4 doi:10.3389/fmars.2019.00751 https://archimer.ifremer.fr/doc/00594/70605/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.3389/fmars.2019.00751 |
container_title |
Frontiers in Marine Science |
container_volume |
6 |
_version_ |
1766383122234998784 |