%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Keerthi, M. G.
%A Prend, C. J.
%A Aumont, Olivier
%A Levy, Marina
%T Annual variations in phytoplankton biomass driven by small-scale physical processes
%D 2022
%L PAR00025264
%G ENG
%J Nature Geoscience
%@ 1752-0894
%K MONDE
%M ISI:000883294100001
%P 1027-1033
%R 10.1038/s41561-022-01057-3
%U https://www.documentation.ird.fr/hor/PAR00025264
%> https://www.documentation.ird.fr/intranet/publi/2024-03/010089890.pdf
%V 15
%W Horizon (IRD)
%X Phytoplankton biomass exhibits substantial year-to-year changes, and understanding these changes is crucial to fisheries management and projecting future climate. These annual changes result partly from low-frequency climate modes that also lead to variations in sea surface temperature (SST). Here we evaluate the contribution of small scales to annual fluctuations based on a global analysis of satellite observations of sea surface chlorophyll (SChl), an indicator of phytoplankton biomass, and of SST from 1999 to 2018. We disentangle the spatio-temporal scales of variability in the time series and find that besides the prominent seasonal cycle, SChl is dominated by high-frequency fluctuations (<three months) at small spatial scales (<50 km)-which accumulates over annual scales in contrast to SST. The results suggest that observations and models with high spatio-temporal resolutions are necessary to understand annual changes in SChl. The rapid response of SChl to small-scale physical processes, combined with intrinsic ecosystem interactions and air-sea interaction feedbacks, may explain the differences between annual variations in SST and SChl. Annual variations of phytoplankton biomass can be explained by processes acting on small spatio-temporal scales, according to a global analysis of satellite observations of sea surface chlorophyll and temperature from 1999 to 2018.
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