Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles
Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global...
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Online Access: | https://doi.org/10.5194/bg-13-4111-2016 https://doaj.org/article/80c9cda1244741efaab2ec5bf0d73d7d |
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ftdoajarticles:oai:doaj.org/article:80c9cda1244741efaab2ec5bf0d73d7d 2023-05-15T18:24:02+02:00 Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles C. Le Quéré E. T. Buitenhuis R. Moriarty S. Alvain O. Aumont L. Bopp S. Chollet C. Enright D. J. Franklin R. J. Geider S. P. Harrison A. G. Hirst S. Larsen L. Legendre T. Platt I. C. Prentice R. B. Rivkin S. Sailley S. Sathyendranath N. Stephens M. Vogt S. M. Vallina 2016-07-01T00:00:00Z https://doi.org/10.5194/bg-13-4111-2016 https://doaj.org/article/80c9cda1244741efaab2ec5bf0d73d7d EN eng Copernicus Publications http://www.biogeosciences.net/13/4111/2016/bg-13-4111-2016.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-13-4111-2016 https://doaj.org/article/80c9cda1244741efaab2ec5bf0d73d7d Biogeosciences, Vol 13, Iss 14, Pp 4111-4133 (2016) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/bg-13-4111-2016 2022-12-31T03:04:59Z Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs): six types of phytoplankton, three types of zooplankton, and heterotrophic procaryotes. We improved the representation of zooplankton dynamics in our model through (a) the explicit inclusion of large, slow-growing macrozooplankton (e.g. krill), and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean high-nutrient low-chlorophyll (HNLC) region during summer. When model simulations do not include macrozooplankton grazing explicitly, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when there is no iron deposition from dust. When model simulations include a slow-growing macrozooplankton and trophic cascades among three zooplankton types, the high-chlorophyll summer bias in the Southern Ocean HNLC region largely disappears. Our model results suggest that the observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community, despite iron limitation of phytoplankton community growth rates. This result has implications for the representation of global biogeochemical cycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Southern Ocean Biogeosciences 13 14 4111 4133 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 C. Le Quéré E. T. Buitenhuis R. Moriarty S. Alvain O. Aumont L. Bopp S. Chollet C. Enright D. J. Franklin R. J. Geider S. P. Harrison A. G. Hirst S. Larsen L. Legendre T. Platt I. C. Prentice R. B. Rivkin S. Sailley S. Sathyendranath N. Stephens M. Vogt S. M. Vallina Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Global ocean biogeochemistry models currently employed in climate change projections use highly simplified representations of pelagic food webs. These food webs do not necessarily include critical pathways by which ecosystems interact with ocean biogeochemistry and climate. Here we present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types (PFTs): six types of phytoplankton, three types of zooplankton, and heterotrophic procaryotes. We improved the representation of zooplankton dynamics in our model through (a) the explicit inclusion of large, slow-growing macrozooplankton (e.g. krill), and (b) the introduction of trophic cascades among the three zooplankton types. We use the model to quantitatively assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean high-nutrient low-chlorophyll (HNLC) region during summer. When model simulations do not include macrozooplankton grazing explicitly, they systematically overestimate Southern Ocean chlorophyll biomass during the summer, even when there is no iron deposition from dust. When model simulations include a slow-growing macrozooplankton and trophic cascades among three zooplankton types, the high-chlorophyll summer bias in the Southern Ocean HNLC region largely disappears. Our model results suggest that the observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community, despite iron limitation of phytoplankton community growth rates. This result has implications for the representation of global biogeochemical cycles in models as zooplankton faecal pellets sink rapidly and partly control the carbon export to the intermediate and deep ocean. |
format |
Article in Journal/Newspaper |
author |
C. Le Quéré E. T. Buitenhuis R. Moriarty S. Alvain O. Aumont L. Bopp S. Chollet C. Enright D. J. Franklin R. J. Geider S. P. Harrison A. G. Hirst S. Larsen L. Legendre T. Platt I. C. Prentice R. B. Rivkin S. Sailley S. Sathyendranath N. Stephens M. Vogt S. M. Vallina |
author_facet |
C. Le Quéré E. T. Buitenhuis R. Moriarty S. Alvain O. Aumont L. Bopp S. Chollet C. Enright D. J. Franklin R. J. Geider S. P. Harrison A. G. Hirst S. Larsen L. Legendre T. Platt I. C. Prentice R. B. Rivkin S. Sailley S. Sathyendranath N. Stephens M. Vogt S. M. Vallina |
author_sort |
C. Le Quéré |
title |
Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
title_short |
Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
title_full |
Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
title_fullStr |
Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
title_full_unstemmed |
Role of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cycles |
title_sort |
role of zooplankton dynamics for southern ocean phytoplankton biomass and global biogeochemical cycles |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/bg-13-4111-2016 https://doaj.org/article/80c9cda1244741efaab2ec5bf0d73d7d |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences, Vol 13, Iss 14, Pp 4111-4133 (2016) |
op_relation |
http://www.biogeosciences.net/13/4111/2016/bg-13-4111-2016.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-13-4111-2016 https://doaj.org/article/80c9cda1244741efaab2ec5bf0d73d7d |
op_doi |
https://doi.org/10.5194/bg-13-4111-2016 |
container_title |
Biogeosciences |
container_volume |
13 |
container_issue |
14 |
container_start_page |
4111 |
op_container_end_page |
4133 |
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1766204313138364416 |