Unexpected winter phytoplankton blooms in ...
Document type :
Article dans une revue scientifique
DOI :
Title :
Unexpected winter phytoplankton blooms in the North Atlantic subpolar gyre
Author(s) :
Lacour, L. [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Ardyna, M. [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Stec, K. F. [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Claustre, Hervé [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Prieur, L. [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Poteau, A. [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Laboratoire d'océanographie de Villefranche [LOV]
Ribera D 'Alcala, M [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Iudicone, D. [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Laboratoire d'océanographie de Villefranche [LOV]
Ardyna, M. [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Stec, K. F. [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Claustre, Hervé [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Prieur, L. [Auteur]
Laboratoire d'océanographie de Villefranche [LOV]
Poteau, A. [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Laboratoire d'océanographie de Villefranche [LOV]
Ribera D 'Alcala, M [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Iudicone, D. [Auteur]
Stazione Zoologica Anton Dohrn [SZN]
Journal title :
Nature Geoscience
Pages :
836 - 839
Publisher :
Nature Publishing Group
Publication date :
2017-10-02
ISSN :
1752-0894
HAL domain(s) :
Sciences de l'environnement/Biodiversité et Ecologie
Planète et Univers [physics]/Océan, Atmosphère
Planète et Univers [physics]/Océan, Atmosphère
English abstract : [en]
In mid-and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination ...
Show more >In mid-and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination with low solar radiation, drastically limits phytoplankton growth during the winter, especially that of the diatoms and other species that are involved in seeding the spring bloom. Here we present observational evidence for widespread winter phytoplankton blooms in a large part of the North Atlantic subpolar gyre from autonomous profiling floats equipped with biogeochemical sensors. These blooms were triggered by intermittent restratification of the mixed layer when mixed-layer eddies led to a horizontal transport of lighter water over denser layers. Combining a bio-optical index with complementary chemotaxonomic and modelling approaches, we show that these restratification events increase phytoplankton residence time in the sunlight zone, resulting in greater light interception and the emergence of winter blooms. Restratification also caused a phytoplankton community shift from pico-and nanophytoplankton to phototrophic diatoms. We conclude that transient winter blooms can maintain active diatom populations throughout the winter months, directly seeding the spring bloom and potentially making a significant contribution to over-winter carbon export.Show less >
Show more >In mid-and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination with low solar radiation, drastically limits phytoplankton growth during the winter, especially that of the diatoms and other species that are involved in seeding the spring bloom. Here we present observational evidence for widespread winter phytoplankton blooms in a large part of the North Atlantic subpolar gyre from autonomous profiling floats equipped with biogeochemical sensors. These blooms were triggered by intermittent restratification of the mixed layer when mixed-layer eddies led to a horizontal transport of lighter water over denser layers. Combining a bio-optical index with complementary chemotaxonomic and modelling approaches, we show that these restratification events increase phytoplankton residence time in the sunlight zone, resulting in greater light interception and the emergence of winter blooms. Restratification also caused a phytoplankton community shift from pico-and nanophytoplankton to phototrophic diatoms. We conclude that transient winter blooms can maintain active diatom populations throughout the winter months, directly seeding the spring bloom and potentially making a significant contribution to over-winter carbon export.Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Source :
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