Decadal variability of phytoplankton abundance in the North Atlantic through atmospheric and oceanic connections

• Main Authors: Martinez, Elodie, Raitsos, Dionysios, Antoine, David
• Other Authors: OPLC, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Red Sea Research Centre (RSRC), King Abdullah University of Science and Technology (KAUST), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), European Project:
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2012
• Subjects: decadal variability; phytoplankton; climate change; North Atlantic; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; North Atlantic oscillation
• Online Access: https://hal.science/hal-00749229

International audience Recent studies using models have reported opposite trends in the past decadal evolution of phytoplankton in the subpolar North Atlantic. In another hand, while long time series of phytoplankton observations are available in this region, they never have been investigated in parallel to physical forcing to understand their variability. Here, we investigated the multi decadal variability of phytoplankton and its underlying mechanisms since the 1960s, thanks to fifty years of in situ observations combined with satellite missions, reanalysed and model products. We show that a phytoplankton increase paralleled a deepening of the mixed layer depth (MLD) since the 1960s. This MLD deepening was related to a strengthening of the winds and net heat loss of the ocean after the mid-1980s following the low frequency signal of the North Atlantic Oscillation. Moreover, the decadal increase of sea surface temperature reported in this region was not associated with the expected scenario of shallower MLD. Our results run counter to the paradigm about how global warming could impact on MLD and phytoplankton abundance.