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General Marine Environmental Science
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A double whammy: ocean hypoxia and acidification interact to influence diatom physiology P-GS-09-S Jiazhen Sun* , State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Tifeng Wang, State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Ruiping Huang, State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Xiangqi Yi, State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Di Zhang, State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Gang Li, Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology Guang Gao, Marine Resources Development Institute of Jiangsu, Huaihai Institute of Technology John Beardall, School of Biological Sciences, Monash University David Hutchins, Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California Kunshan Gao, State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University Presenter Email: iamvurtne@sina.com |
Oxygen is essential to respiration of most marine organisms. However, the oxygen concentration in seawater has been being declining, both in open oceans as well as in coastal waters, as a consequence of global warming and coastal eutrophication1. As a result, the extent of hypoxic waters is expanding2, deteriorating habitable environments for a wide range of marine biota. However, it is still unknown how marine photosynthesis will respond to such climate forcing in combination with ocean acidification. Here, we show that under experimental deoxygenation conditions, the diatom Thalassiosira weissflogi grows faster, respires less and shows faster rates of photosynthesis, with its CO2 concentrating mechanisms (CCMs) significantly up-regulated. Such stimulation of CCMs are associated with inhibition of photorespiration as consequence of Rubisco-catalyzed carboxylation and oxygenation shifting to favor CO2 fixation, that in turn enhances photosynthesis and net O2 production. Field measurements showed increased phytoplankton primary productivity at reduced oxygen concentrations, supporting our laboratory finding that deoxygenation enhances algal photosynthesis. Our results suggest that marine primary producers can benefit from ocean changes in pO2/pCO2. |
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