Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific.

Autor:	Smith KL Jr; Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039; ksmith@mbari.org., Ruhl HA; Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039.; National Oceanography Centre, University of Southampton, SO14 3ZH Southampton, United Kingdom., Huffard CL; Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039., Messié M; Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039.; Aix Marseille Université, Université de Toulon, CNRS, Institut de Recherche pour le Développement (IRD), Mediterranean Institute of Oceanography (MIO), Unité Mixte 110, 13288 Marseille, France., Kahru M; Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2018 Nov 27; Vol. 115 (48), pp. 12235-12240. Date of Electronic Publication: 2018 Nov 14.
DOI:	10.1073/pnas.1814559115
Abstrakt:	Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events (≥mean + 2 σ), and 43% from 2011 to 2017. From 2011 to 2017, when high-resolution SCOC data were available, time lags between changes in satellite-estimated export flux (EF), POC flux, and SCOC on the sea floor varied between six flux events from 0 to 70 days, suggesting variable remineralization rates and/or particle sinking speeds. Half of POC flux pulse events correlated with prior increases in EF and/or subsequent SCOC increases. Peaks in EF overlying Station M frequently translated to changes in POC flux at abyssal depths. A power-law model (Martin curve) was used to estimate abyssal fluxes from EF and midwater temperature variation. While the background POC flux at 3,400-m depth was described well by the model, the episodic events were significantly underestimated by ∼80% and total flux by almost 50%. Quantifying episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of POC sequestration and understanding the global carbon cycle. Competing Interests: The authors declare no conflict of interest. (Copyright © 2018 the Author(s). Published by PNAS.)
Databáze:	MEDLINE
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