Wildfire aerosol deposition likely amplified a summertime Arctic phytoplankton bloom

Mathieu Ardyna (1, 2) , Douglas S. Hamilton , Tristan Harmel (3) , Léo Lacour (4, 1) , Diana N. Bernstein , Julien Laliberté (4, 2) , Christopher Horvat , Rémi Laxenaire (5, 6) , Matthew M. Mills , Gert van Dijken , Igor Polyakov , Hervé Claustre (1) , Natalie Mahowald , Kevin Robert Arrigo

1 LOV - Laboratoire d'océanographie de Villefranche
2 Takuvik Joint International Laboratory ULAVAL-CNRS
3 GET - Géosciences Environnement Toulouse
4 CNRS - Centre National de la Recherche Scientifique
5 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
6 LACy - Laboratoire de l'Atmosphère et des Cyclones

Summertime wildfire activity is increasing in boreal forest and tundra ecosystems in the Northern Hemisphere. However, the impact of long range transport and deposition of wildfire aerosols on biogeochemical cycles in the Arctic Ocean is unknown. Here, we use satellite-based ocean color data, atmospheric modeling and back trajectory analysis to investigate the transport and fate of aerosols emitted from Siberian wildfires in summer 2014 and their potential impact on phytoplankton dynamics in the Arctic Ocean. We detect large phytoplankton blooms near the North Pole (up to 82°N in the eastern Eurasian Basin). Our analysis indicates that these blooms were induced by the northward plume transport and deposition of nutrient-bearing wildfire aerosols. We estimate that these highly stratified surface waters received large amounts of wildfire-derived nitrogen, which alleviated nutrient stress in the phytoplankton community and triggered an unusually large bloom event. Our findings suggest that changes in wildfire activity may strongly influence summertime productivity in the Arctic Ocean.

Domaines: Planète et Univers [physics]

Mathieu Ardyna, Douglas S. Hamilton, Tristan Harmel, Léo Lacour, Diana N. Bernstein, et al.. Wildfire aerosol deposition likely amplified a summertime Arctic phytoplankton bloom. Communications Earth & Environment, 2022, 3, ⟨10.1038/s43247-022-00511-9⟩. ⟨insu-03824434⟩