Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 15, issue 16
Biogeosciences, 15, 5155-5167, 2018
https://doi.org/10.5194/bg-15-5155-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Biogeosciences, 15, 5155-5167, 2018
https://doi.org/10.5194/bg-15-5155-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 28 Aug 2018

Research article | 28 Aug 2018

Basin-scale variability of microbial methanol uptake in the Atlantic Ocean

Stephanie L. Sargeant1,a, J. Colin Murrell2, Philip D. Nightingale1, and Joanna L. Dixon1 Stephanie L. Sargeant et al.
  • 1Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth, Devon, PL1 3DH, UK
  • 2School of Environmental Science, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
  • anow at: Centre for Research in Biosciences, University of the West of England, Frenchay Campus, Coldharbour Lane, Bristol, BS16 1QY, UK

Abstract. Methanol is a climate-active gas and the most abundant oxygenated volatile organic compound (OVOC) in the atmosphere and seawater. Marine methylotrophs are aerobic bacteria that utilise methanol from seawater as a source of carbon (assimilation) and/or energy (dissimilation). A few spatially limited studies have previously reported methanol oxidation rates in seawater; however, the basin-wide ubiquity of marine microbial methanol utilisation remains unknown. This study uniquely combines seawater 14C labelled methanol tracer studies with 16S rRNA pyrosequencing to investigate variability in microbial methanol dissimilation and known methanol-utilising bacteria throughout a meridional transect of the Atlantic Ocean between 47°N to 39°S. Microbial methanol dissimilation varied between 0.05 and 1.68nmolL−1h−1 in the top 200m of the Atlantic Ocean and showed significant variability between biogeochemical provinces. The highest rates of methanol dissimilation were found in the northern subtropical gyre (average 0.99±0.41nmolL−1h−1), which were up to 8 times greater than other Atlantic regions. Microbial methanol dissimilation rates displayed a significant inverse correlation with heterotrophic bacterial production (determined using 3H-leucine). Despite significant depth stratification of bacterial communities, methanol dissimilation rates showed much greater variability between oceanic provinces compared to depth. There were no significant differences in rates between samples collected under light and dark environmental conditions. The variability in the numbers of SAR11 (16S rRNA gene sequences) were estimated to explain approximately 50% of the changes in microbial methanol dissimilation rates. We estimate that SAR11 cells in the Atlantic Ocean account for between 0.3% and 59% of the rates of methanol dissimilation in Atlantic waters, compared to <0.01%–2.3% for temperate coastal waters. These results make a substantial contribution to our current knowledge and understanding of the utilisation of methanol by marine microbial communities, but highlight the lack of understanding of in situ methanol production mechanisms.

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Methanol is a climate-active gas and the most abundant oxygenated volatile organic compound in the atmosphere and seawater. This study uniquely combines methanol tracer uptake experiments with 16S rRNA pyrosequencing to show basin-wide microbial methanol uptake throughout the top 200 m of the Atlantic Ocean. These rates showed a positive correlation with the numbers of SAR11 16S rRNA gene sequences, suggesting these numerous bacteria are important sinks for methanol in seawater.
Methanol is a climate-active gas and the most abundant oxygenated volatile organic compound in...
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