Abundance and distribution of archaeal acetyl-CoA/propionyl-CoA carboxylase genes indicative for putatively chemoautotrophic Archaea in the tropical Atlantic's interior

Author(s)
Kristin Bergauer, Eva Sintes Elvelin, Judith van Bleijswijk, Harry Witte, Gerhard J. Herndl
Abstract

Recently, evidence suggests that dark CO2 fixation in the pelagic realm of the ocean does not only occur in the suboxic and anoxic water bodies but also in the oxygenated meso- and bathypelagic waters of the North Atlantic. To elucidate the significance and phylogeny of the key organisms mediating dark CO2 fixation in the tropical Atlantic, we quantified functional genes indicative for CO2 fixation. We used a Q-PCR-based assay targeting the bifunctional acetyl-CoA/propionyl-CoA carboxylase (accA subunit), a key enzyme powering inter alia the 3-hydroxypropionate/4-hydroxybutyrate cycle (HP/HB) and the archaeal ammonia monooxygenase (amoA). Quantification of accA-like genes revealed a consistent depth profile in the upper mesopelagial with increasing gene abundances from subsurface layers towards the oxygen minimum zone (OMZ), coinciding with an increase in archaeal amoA gene abundance. Gene abundance profiles of metabolic marker genes (accA, amoA) were correlated with thaumarchaeal 16S rRNA gene abundances as well as CO2 fixation rates to link the genetic potential to actual rate measurements. AccA gene abundances correlated with archaeal amoA gene abundance throughout the water column (r2 = 0.309, P < 0.0001). Overall, a substantial genetic predisposition of CO2 fixation was present in the dark realm of the tropical Atlantic in both Archaea and Bacteria. Hence, dark ocean CO2 fixation might be more widespread among prokaryotes inhabiting the oxygenated water column of the ocean's interior than hitherto assumed.

Organisation(s)
External organisation(s)
Royal Netherlands Institute for Sea Research
Journal
FEMS microbiology ecology
Volume
84
Pages
461-473
No. of pages
13
ISSN
0168-6496
DOI
https://doi.org/10.1111/1574-6941.12073
Publication date
06-2013
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
Keywords
ASJC Scopus subject areas
Ecology, Applied Microbiology and Biotechnology, Microbiology
Portal url
https://ucris.univie.ac.at/portal/en/publications/abundance-and-distribution-of-archaeal-acetylcoapropionylcoa-carboxylase-genes-indicative-for-putatively-chemoautotrophic-archaea-in-the-tropical-atlantics-interior(5397b0f0-96f0-42a3-a4fb-134bc8d7f013).html