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A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies

Strong tropical cyclone (TC) Ockhi occurred in the southeastern Arabian Sea (AS) in 2017. Ockhi greatly changed the oceanic conditions and induced large variation in chlorophyll-a (Chl-a). The dynamic mechanisms of the long-term phytoplankton bloom after the passage of the TC were investigated in th...

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Autores principales: Lü, Haibin, Zhao, Xingyu, Sun, Jialong, Zha, Guozhen, Xi, Jingyuan, Cai, Shuqun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147795/
https://www.ncbi.nlm.nih.gov/pubmed/32275722
http://dx.doi.org/10.1371/journal.pone.0230394
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author Lü, Haibin
Zhao, Xingyu
Sun, Jialong
Zha, Guozhen
Xi, Jingyuan
Cai, Shuqun
author_facet Lü, Haibin
Zhao, Xingyu
Sun, Jialong
Zha, Guozhen
Xi, Jingyuan
Cai, Shuqun
author_sort Lü, Haibin
collection PubMed
description Strong tropical cyclone (TC) Ockhi occurred in the southeastern Arabian Sea (AS) in 2017. Ockhi greatly changed the oceanic conditions and induced large variation in chlorophyll-a (Chl-a). The dynamic mechanisms of the long-term phytoplankton bloom after the passage of the TC were investigated in this study. Prominent surface ocean responses, e.g., decreasing temperature and salinity, were identified from Argo data by comparing the pre- and post-conditions of the TC. A phytoplankton bloom was observed in southeastern AS after the passage of TC Ockhi within the area of (11°N-14°N, 67°E-70°E) and lasted for seven days. Interestingly, there were two weaker cyclonic eddies, with an average vorticity of less than 0.14 s(-1), on the TC trajectory from November 28 to December 2. As Ockhi approached, strong vertical mixing occurred on December 3, increasing the eddy vorticity to 0.26 s(-1). After the passage of Ockhi, both eddies, with a two-day oscillation period, were substantially enhanced. Especially from December 11 to 16, the vorticity above 70 m was as high as 0.2 s(-1) in the thermocline. Because of the high photosynthetically available radiation (PAR) and low precipitation, the enhanced cyclonic eddies induced upwelling for the entire thermocline for over ten days and uplifted nitrates into the mixed layer. This study offers new insights on the influence of eddies in regulating the impacts of typhoons on Chl-a, and the results can help evaluate typhoon-induced biological responses in the future.
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spelling pubmed-71477952020-04-14 A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies Lü, Haibin Zhao, Xingyu Sun, Jialong Zha, Guozhen Xi, Jingyuan Cai, Shuqun PLoS One Research Article Strong tropical cyclone (TC) Ockhi occurred in the southeastern Arabian Sea (AS) in 2017. Ockhi greatly changed the oceanic conditions and induced large variation in chlorophyll-a (Chl-a). The dynamic mechanisms of the long-term phytoplankton bloom after the passage of the TC were investigated in this study. Prominent surface ocean responses, e.g., decreasing temperature and salinity, were identified from Argo data by comparing the pre- and post-conditions of the TC. A phytoplankton bloom was observed in southeastern AS after the passage of TC Ockhi within the area of (11°N-14°N, 67°E-70°E) and lasted for seven days. Interestingly, there were two weaker cyclonic eddies, with an average vorticity of less than 0.14 s(-1), on the TC trajectory from November 28 to December 2. As Ockhi approached, strong vertical mixing occurred on December 3, increasing the eddy vorticity to 0.26 s(-1). After the passage of Ockhi, both eddies, with a two-day oscillation period, were substantially enhanced. Especially from December 11 to 16, the vorticity above 70 m was as high as 0.2 s(-1) in the thermocline. Because of the high photosynthetically available radiation (PAR) and low precipitation, the enhanced cyclonic eddies induced upwelling for the entire thermocline for over ten days and uplifted nitrates into the mixed layer. This study offers new insights on the influence of eddies in regulating the impacts of typhoons on Chl-a, and the results can help evaluate typhoon-induced biological responses in the future. Public Library of Science 2020-04-10 /pmc/articles/PMC7147795/ /pubmed/32275722 http://dx.doi.org/10.1371/journal.pone.0230394 Text en © 2020 Lü et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Lü, Haibin
Zhao, Xingyu
Sun, Jialong
Zha, Guozhen
Xi, Jingyuan
Cai, Shuqun
A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title_full A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title_fullStr A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title_full_unstemmed A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title_short A case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
title_sort case study of a phytoplankton bloom triggered by a tropical cyclone and cyclonic eddies
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7147795/
https://www.ncbi.nlm.nih.gov/pubmed/32275722
http://dx.doi.org/10.1371/journal.pone.0230394
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