Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

Author(s)
Christian Lønborg, L. Antonio Cuevas, Thomas Reinthaler, Gerhard J. Herndl, Josep M. Gasol, Xosé Anxelu G. Morán, Nicholas R. Bates, Xosé A. Álvarez-Salgado
Abstract

Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0–200 m), meso- (201–1,000m) and bathypelagic waters (1,001–4,000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (Ea) of 36 ± 7 kJ mol–1 for the epipelagic, 72 ± 15 kJ mol–1 for the mesopelagic and 274 ± 65 kJ mol–1 for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12 and 55% in the epi-, meso- and bathypelagic ocean, respectively, in response to a water temperature increase by 1ºC. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activity.

Organisation(s)
Department of Limnology and Bio-Oceanography
Journal
Frontiers in Marine Science
Volume
3
Pages
90
No. of pages
9
ISSN
2296-7745
DOI
https://doi.org/10.3389/fmars.2016.00090
Publication date
2016
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology, 105306 Oceanography
Portal url
https://ucris.univie.ac.at/portal/en/publications/depth-dependent-relationships-between-temperature-and-ocean-heterotrophic-prokaryotic-production(ca844645-4d5a-45a6-a0f8-e4948aded931).html