Empirical leucine-to-carbon conversion factors in north-eastern Atlantic waters (50-200 m) shaped by bacterial community composition and optical signature of DOM

Article research Microbial heterotrophic activity is a major process regulating the flux of dissolved organic matter (DOM) in the ocean, while the characteristics of this DOM strongly influence its microbial utilization and fate in the ocean. In order to broaden the vertical resolution of leucine-to...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Orta-Ponce, C.P. (Cessna Pamela), Rodríguez-Ramos, T. (Tamara), Nieto-Cid, M. (Mar), Teira, E. (Eva), Guerrero-Feijóo, E. (Elisa), Bode, A. (Antonio), Varela, M.M. (Marta María)
Format: Article in Journal/Newspaper
Language:English
Published: Centro Oceanográfico de A Coruña 2021
Subjects:
leucine-to carbon conversion factors
NE Atlantic Ocean
Bacterial community composition
DOM
community composition
dissolved organic matter
organic matter
conversion factors
Nordeste
North Atlantic
Northeast Atlantic
Online Access:http://hdl.handle.net/10508/16466
https://doi.org/10.1038/s41598-021-03790-y
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Summary:Article research Microbial heterotrophic activity is a major process regulating the flux of dissolved organic matter (DOM) in the ocean, while the characteristics of this DOM strongly influence its microbial utilization and fate in the ocean. In order to broaden the vertical resolution of leucine-to-carbon conversion factors (CFs), needed for converting substrate incorporation into biomass production by heterotrophic bacteria, 20 dilution experiments were performed in the North Atlantic Ocean. We found a depth-stratification in empirical CFs values from epipelagic to bathypelagic waters (4.00 ± 1.09 to 0.10 ± 0.00 kg C mol Leu−1). Our results demonstrated that the customarily used theoretical CF of 1.55 kg C mol Leu−1 in oceanic samples can lead to an underestimation of prokaryotic heterotrophic production in epi- and mesopelagic waters, while it can overestimate it in the bathypelagic ocean. Pearson correlations showed that CFs were related not only to hydrographic variables such as temperature, but also to specific phylogenetic groups and DOM quality and quantity indices. Furthermore, a multiple linear regression model predicting CFs from relatively simple hydrographic and optical spectroscopic measurements was attempted. Taken together, our results suggest that differences in CFs throughout the water column are significantly connected to DOM, and also reflect differences linked to specific prokaryotic groups. 2,927

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