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Interacting effects of ocean acidification and warming on growth and DMS ‐production in the haptophyte coccolithophore E miliania huxleyi
Author(s) -
Arnold Hayley E.,
Kerrison Philip,
Steinke Michael
Publication year - 2013
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12105
Subject(s) - haptophyte , coccolithophore , emiliania huxleyi , environmental science , oceanography , global warming , chemistry , phytoplankton , climate change , ecology , biology , geology , nutrient
The production of the marine trace gas dimethyl sulfide ( DMS ) provides 90% of the marine biogenic sulfur in the atmosphere where it affects cloud formation and climate. The effects of increasing anthropogenic CO 2 and the resulting warming and ocean acidification on trace gas production in the oceans are poorly understood. Here we report the first measurements of DMS ‐production and data on growth, DMSP and DMS concentrations in pH‐stated cultures of the phytoplankton haptophyte E miliania huxleyi . Four different environmental conditions were tested: ambient, elevated CO 2 (+ CO 2 ), elevated temperature (+ T ) and elevated temperature and CO 2 (+ TCO 2 ). In comparison to the ambient treatment, average DMS production was about 50% lower in the + CO 2 treatment. Importantly, temperature had a strong effect on DMS production and the impacts outweighed the effects of a decrease in pH. As a result, the + T and + TCO 2 treatments showed significantly higher DMS production of 36.2 ± 2.58 and 31.5 ± 4.66 μmol L −1 cell volume ( CV ) h −1 in comparison with the + CO 2 treatment (14.9 ± 4.20 μmol L −1 CV h −1 ). As the cultures were aerated with an air/ CO 2 mixture, DMS was effectively removed from the incubation bottles so that concentration remained relatively low (3.6–6.1 mmol L −1 CV). Intracellular DMSP has been shown to increase in E . huxleyi as a result of elevated temperature and/or elevated CO 2 and our results are in agreement with this finding: the ambient and + CO 2 treatments showed 125 ± 20.4 and 162 ± 27.7 mmol L −1 CV, whereas + T and + TCO 2 showed significantly increased intracellular DMSP concentrations of 195 ± 15.8 and 211 ± 28.2 mmol L −1 CV respectively. Growth was unaffected by the treatments, but cell diameter decreased significantly under elevated temperature. These results indicate that DMS production is sensitive to CO 2 and temperature in E . huxleyi . Hence, global environmental change that manifests in ocean acidification and warming may not result in decreased DMS as suggested by earlier studies investigating the effect of elevated CO 2 in isolation.