Warming the phycosphere: differential effect of temperature on the use of diatom-derived carbon by two copiotrophic bacterial taxa.
Richnow, Hans H
Moran, Xose Anxelu G.
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Marine Science Program
Microbial oceanography Research Group
Red Sea Research Center (RSRC)
Online Publication Date2020-02-24
Print Publication Date2020-04
Embargo End Date2021-02-25
Permanent link to this recordhttp://hdl.handle.net/10754/661696
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AbstractHeterotrophic bacteria associated with microphytoplankton, particularly those colonizing the phycosphere, are major players in the remineralization of algal-derived carbon. Ocean warming might impact DOC uptake by microphytoplankton-associated bacteria with unknown biogeochemical implications. Here, by incubating natural seawater samples at 3 different temperatures we analyzed the effect of experimental warming on the abundance and C and N uptake activity of Rhodobacteraceae and Flavobacteria, two bacterial groups typically associated with microphytoplankton. Using NanoSIMS single-cell analysis we quantified the temperature-sensitivity of these two taxonomic groups to the uptake of algal-derived DOC in the microphytoplankton-associated fraction with 13 C-bicarbonate and 15 N-leucine as tracers. We found that cell-specific 13 C uptake was similar for both groups (~0.42 fg C h-1 μm-3 ), but Rhodobacteraceae were more active in 15 N-leucine uptake. Due to the higher abundance of Flavobacteria associated with microphytoplankton, this group incorporated 4-fold more carbon than Rhodobacteraceae. Cell-specific 13 C uptake was influenced by temperature, but no significant differences were found for 15 N-leucine uptake. Our results show that the contribution of Flavobacteria and Rhodobacteraceae to C assimilation increased up to 6-fold and 2-fold, respectively, with an increase of 3°C above ambient temperature, suggesting that warming may differently affect the contribution of distinct copiotrophic bacterial taxa to carbon cycling. This article is protected by copyright. All rights reserved.
CitationArandia-Gorostidi, N., Alonso-Sáez, L., Stryhanyuk, H., Richnow, H. H., Morán, X. A. G., & Musat, N. (2020). Warming the phycosphere: differential effect of temperature on the use of diatom-derived carbon by two copiotrophic bacterial taxa. Environmental Microbiology. doi:10.1111/1462-2920.14954
SponsorsWe are grateful to Basque Government for supporting N.A.G.’s Ph.D. fellowship the Spanish Ministry of Economy and Competitiveness (MINECO) for supporting L.A.S.’s Juan de la Cierva and Ramón y Cajal (RYC-2012-11404) fellowships and the COMITE project (CTM-2010–15840). We thank the Helmholtz Centre for Environmental Research and the Department of Isotope Biogeochemistry for providing the access to their infrastructure (ProVIS) and to M. G. for the EA-MS analysis. We are very thankful to all the staff of the R/V “José de Rioja” for their help during the sampling collection and L. Díaz and T.M. Huete-Stauffer for their help during the experiments.