Major contribution of autotrophy to microbial carbon cycling in the deep North Atlantic's interior

Author(s)
Thomas Reinthaler, Hendrik M. van Aken, Gerhard Herndl
Abstract

Current estimates point to a mismatch of particulate organic carbon supply derived from the surface ocean and the microbial organic carbon demand in the meso- and bathypelagic realm. Based on recent findings that chemoautotrophic Crenarchaeota are abundant in the mesopelagic zone, we quantified dissolved inorganic carbon (DIC) fixation in the meso- and bathypelagic North Atlantic and compared it with heterotrophic microbial activity. Measuring C-14-bicarbonate fixation and H-3-leucine incorporation revealed that microbial DIC fixation is substantial in the mesopelagic water masses, ranging from 0.1 to 56.7 iimol C m(-3) d(-1), and is within the same order of magnitude as heterotrophic microbial activity. Integrated over the dark ocean's water column, DIC fixation ranged from 1-2.5 mmol C m(-2) d(-1), indicating that chemoautotrophy in the dark ocean represents a significant source of autochthonously produced 'new organic carbon' in the ocean's interior amounting to about 15-53% of the phytoplankton export production. Hence, chemoautotrophic DIC fixation in the oxygenated meso- and bathypelagic water column of the North Atlantic might substantially contribute to the organic carbon demand of the deep-water microbial food web.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
Royal Netherlands Institute for Sea Research
Journal
Deep-Sea Research. Part 2: Topical Studies in Oceanography
Volume
57
Pages
1572-1580
No. of pages
9
ISSN
0967-0645
DOI
https://doi.org/10.1016/j.dsr2.2010.02.023
Publication date
2010
Peer reviewed
Yes
Austrian Fields of Science 2012
106026 Ecosystem research, 105105 Geochemistry, 106022 Microbiology
Portal url
https://ucris.univie.ac.at/portal/en/publications/major-contribution-of-autotrophy-to-microbial-carbon-cycling-in-the-deep-north-atlantics-interior(386cad1c-b34a-4ae8-bb76-4601cb8e5a1d).html