Extreme value distributions describe interannual variability in the seasonal North Atlantic phytoplankton bloom

Abstract The North Atlantic phytoplankton bloom depends on a confluence of environmental factors that drive transient periods of exponential phytoplankton growth and interannual variability in bloom magnitude. I analyze interannual bloom variability in the North Atlantic via extreme value theory whe...

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Bibliographic Details
Published in:Limnology and Oceanography Letters
Main Author: Gregory L. Britten
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2022
Subjects:
Online Access:https://doi.org/10.1002/lol2.10247
https://doaj.org/article/b5382329df3f4a7bba4d36ce48e67f56
Description
Summary:Abstract The North Atlantic phytoplankton bloom depends on a confluence of environmental factors that drive transient periods of exponential phytoplankton growth and interannual variability in bloom magnitude. I analyze interannual bloom variability in the North Atlantic via extreme value theory where the generalized extreme value distribution (GEVD) is fitted spatially to annual maxima of satellite‐measured surface chlorophyll. I find excellent agreement between the observed distribution of interannual bloom maxima and those predicted from the GEVD. The spatial distribution of fitted GEVD parameters closely follows basin bathymetry where the largest extremes and heaviest distribution tails are found on the continental shelves and slopes. Trend analyses suggest weak evidence for changes in GEVD parameters, despite regional trends in mean chlorophyll levels and sea surface temperature. These results provide a framework to quantify interannual bloom variability and call for further work examining how extreme blooms propagate through food webs and contribute to carbon export.