Silicic acid limitation drives bloom termination and potential carbon sequestration in an Arctic bloom.

Autor: Krause JW; Dauphin Island Sea Lab, Dauphin Island, AL, USA. jkrause@disl.edu.; Department of Marine Sciences, University of South Alabama, Mobile, AL, USA. jkrause@disl.edu., Schulz IK; Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia., Rowe KA; Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia., Dobbins W; Dauphin Island Sea Lab, Dauphin Island, AL, USA., Winding MHS; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland., Sejr MK; Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark., Duarte CM; Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.; Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark., Agustí S; Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2019 May 31; Vol. 9 (1), pp. 8149. Date of Electronic Publication: 2019 May 31.
DOI: 10.1038/s41598-019-44587-4
Abstrakt: The spring diatom bloom in the Arctic Ocean accounts for significant annual primary production leading to the most rapid annual drawdown of water-column pCO 2 . Late-winter waters in the Atlantic Arctic & Subarctic Provinces (AASP) have lower silicic acid concentrations than nitrate, which suggests diatom blooms may deplete Si before N. Here we test a facet of the hypothesis that silicic acid limitation terminates the spring diatom bloom in the AASP and the sinking of the senescent and dead diatoms helps drive carbon sequestration. During a 6-week study, diatoms bloomed and progressively consumed silicic acid to where it limited their growth. The onset of growth limitation was concurrent with the minimum pCO 2 in the surface waters and increases in both the proportion of dead diatoms and the diatom assemblage sedimentation rate. Data reanalysis within the AASP shows a highly significant and positive correlation between silicic acid and pCO 2 in the surface waters, but no significant relationship with nitrate and pCO 2 was observed unless data were smoothed. Therefore, understanding the future of the AASP spring diatom bloom requires models that explicitly consider changes in silicic acid supply as a driver of this process.
Databáze: MEDLINE
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