Biological and physical influences on marine snowfall at the equator.

Kiko, Rainer , Biastoch, Arne , Brandt, Peter , Cravatte, S., Hauss, Helena , Hummels, Rebecca, Kriest, Iris , Marin, F., McDonnell, A. M. P., Oschlies, Andreas , Picheral, M., Schwarzkopf, Franziska U. , Thurnherr, A. M. and Stemmann, L. (2017) Biological and physical influences on marine snowfall at the equator. Nature Geoscience, 10 (11). pp. 852-858. DOI 10.1038/ngeo3042.

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Supplementary data:

Abstract

High primary productivity in the equatorial Atlantic and Pacific oceans is one of the key features of tropical ocean biogeochemistry and fuels a substantial flux of particulate matter towards the abyssal ocean. How biological processes and equatorial current dynamics shape the particle size distribution and flux, however, is poorly understood. Here we use high-resolution size-resolved particle imaging and Acoustic Doppler Current Profiler data to assess these influences in equatorial oceans. We find an increase in particle abundance and flux at depths of 300 to 600 m at the Atlantic and Pacific equator, a depth range to which zooplankton and nekton migrate vertically in a daily cycle. We attribute this particle maximum to faecal pellet production by these organisms. At depths of 1,000 to 4,000 m, we find that the particulate organic carbon flux is up to three times greater in the equatorial belt (1° S–1° N) than in off-equatorial regions. At 3,000 m, the flux is dominated by small particles less than 0.53 mm in diameter. The dominance of small particles seems to be caused by enhanced active and passive particle export in this region, as well as by the focusing of particles by deep eastward jets found at 2° N and 2° S. We thus suggest that zooplankton movements and ocean currents modulate the transfer of particulate carbon from the surface to the deep ocean.

Document Type: Article
Keywords: Carbon cycle; Marine biology; Physical oceanography
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BM Biogeochemical Modeling
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-N Experimental Ecology - Food Webs
OceanRep > SFB 754
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
OceanRep > SFB 754 > B1
OceanRep > SFB 754 > B8
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1038/ngeo3042
ISSN: 1752-0894
Related URLs:
Projects: SFB754, RACE, OCEANOMICS
Expeditions/Models/Experiments:
Date Deposited: 08 Nov 2017 10:43
Last Modified: 25 Feb 2019 14:13
URI: http://oceanrep.geomar.de/id/eprint/40088

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