Nitrogen Limitation of the Summer Phytoplankton and Heterotrophic Prokaryote Communities in the Chukchi Sea - Laboratoire d'Océanographie Microbienne Accéder directement au contenu
Article Dans Une Revue Frontiers in Marine Science Année : 2018

Nitrogen Limitation of the Summer Phytoplankton and Heterotrophic Prokaryote Communities in the Chukchi Sea

Résumé

Major changes to Arctic marine ecosystems have resulted in longer growing seasons with increased phytoplankton production over larger areas. In the Chukchi Sea, the high productivity fuels intense benthic denitrification creating a nitrogen (N) deficit that is transported through the Arctic to the Atlantic Ocean, where it likely fuels N fixation. Given the rapid pace of environmental change and the potentially globally significant N deficit, we conducted experiments aimed at understanding phytoplankton and microbial N utilization in the Chukchi Sea. Ship-board experiments tested the effect of nitrate (NO 3 −) additions on both phytoplankton and heterotrophic prokaryote abundance, community composition, photophysiology, carbon fixation and NO 3 − uptake rates. Results support the critical role of NO 3 − in limiting summer phytoplankton communities to small cells with low production rates. NO 3 − additions increased particulate concentrations, abundance of large diatoms, and rates of carbon fixation and NO 3 − uptake by cells >1 µm. Increases in the quantum yield and electron turnover rate of photosystem II in +NO 3 − treatments suggested that phytoplankton in the ambient dissolved N environment were N starved and unable to build new, or repair damaged, reaction centers. While some increases in heterotrophic prokaryote abundance and production were noted with NO 3 − amendments, phytoplankton competition or grazers likely dampened these responses. Trends toward a warmer more stratified Chukchi Sea will likely enhance summer oligotrophic conditions and further N starve Chukchi Sea phytoplankton communities.
Fichier principal
Vignette du fichier
fmars-05-00362.pdf (7.37 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-04002590 , version 1 (23-02-2023)

Identifiants

Citer

Matthew M Mills, Zachary W Brown, Samuel R Laney, Eva Ortega-Retuerta, Kate E Lowry, et al.. Nitrogen Limitation of the Summer Phytoplankton and Heterotrophic Prokaryote Communities in the Chukchi Sea. Frontiers in Marine Science, 2018, 5, pp.362. ⟨10.3389/fmars.2018.00362⟩. ⟨hal-04002590⟩
85 Consultations
58 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More