title: Resilience of SAR11 bacteria to rapid acidification in the high-latitude open ocean.
abstract: Ubiquitous SAR11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short-term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of SAR11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic SAR11. This study investigated the effect of 2.5-fold acidification of seawater on the metabolism of SAR11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake rates of the amino acid leucine by SAR11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects.
authors.affiliation: National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, UK.
authors.forename: Manuela
authors.initials: M
authors.lastname: Hartmann
authors.affiliation: National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, UK.
authors.forename: Polly G
authors.initials: PG
authors.lastname: Hill
authors.affiliation: School of Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, UK.
authors.forename: Eithne
authors.initials: E
authors.lastname: Tynan
authors.affiliation: School of Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, UK GEOMAR Helmholtz Centre for Ocean Research, D-24148 Kiel, Germany.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Achterberg
authors.affiliation: Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, UK.
authors.forename: Raymond J G
authors.initials: RJ
authors.lastname: Leakey
authors.affiliation: National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, UK mvz@noc.ac.uk.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Zubkov
mesh_terms: D020561:Alphaproteobacteria / Q000378:metabolism*; D059001:Aquatic Organisms / Q000378:metabolism; D001267:Atlantic Ocean; D001692:Biological Transport / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism*; D006116:Greenland; D006863:Hydrogen-Ion Concentration; D007930:Leucine / Q000378:metabolism*; D009792:Oceans and Seas; D010933:Plankton / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology; D013696:Temperature
chemical_list: D002245:Carbon Dioxide; D007930:Leucine
keywords: CARD-FISH; flow cytometric cell sorting; isotopic tracer labelling; pCO2 perturbation