Temperature control of microbial respiration and growth efficiency in the mesopelagic zone of the South Atlantic and Indian Oceans

We have measured both prokaryotic heterotrophic production (PHP) and respiration (R), then providing direct estimates of prokaryotic growth efficiencies (PGE), in the upper mesopelagic zone (300–600 m) of the South Atlantic and Indian Oceans. Our results show that in situ R ranged 3-fold, from 87 to...

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Bibliographic Details
Published in:Deep Sea Research Part I: Oceanographic Research Papers
Main Authors: Mazuecos, Ignacio P., Aristegui, Javier, Vázquez-Domínguez, Evaristo, Ortega-Retuerta, Eva, Gasol, Josep M., Reche, Isabel
Other Authors: Gasol, Josep M, 36542617400, 7006816204, 17136364200, 14063577900, 7003299234, 6603791726, 5965710, 227201, 2146947, 1462677, 97985, 676677, WOS:Mazuecos, IP, WOS:Aristegui, J, WOS:Vazquez-Dominguez, E, WOS:Ortega-Retuerta, E, WOS:Gasol, JM, WOS:Reche, I
Format: Article in Journal/Newspaper
Language:English
Published: 0967-0637 2015
Subjects:
251001 Oceanografía biológica
Mesopelagic zone
Microbial respiration
Prokaryotic growth efficiency
Temperature
Indian Ocean
South Atlantic Ocean
Indian
Online Access:http://hdl.handle.net/10553/51628
https://doi.org/10.1016/j.dsr.2014.10.014
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Summary:We have measured both prokaryotic heterotrophic production (PHP) and respiration (R), then providing direct estimates of prokaryotic growth efficiencies (PGE), in the upper mesopelagic zone (300–600 m) of the South Atlantic and Indian Oceans. Our results show that in situ R ranged 3-fold, from 87 to 238 μmol C m−3 d−1. In situ PHP rates were much lower but also more variable than R (ranging from 0.3 to 9.1 μmol C m−3 d−1). The derived in situ PGE values were on average ~1.4% (from 0.3% to 3.7%), indicating that most of the organic substrates incorporated by prokaryotes were respired instead of being used for growth. Together with the few previous studies on PGE published before for the Atlantic Ocean and Mediterranean Sea, our findings support the hypothesis that the global mesopelagic zone represents a key remineralization site for export production in the open ocean. We also found a strong correlation between R and PGE with temperature across a gradient ranging from 8.7 to 14.9 °C. The derived Q10 value of 3.7 suggests that temperature variability in the mesopelagic zone plays a significant role in the remineralization of organic matter. 138 131 1,369 2,684 Q1 Q1 SCIE

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