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Nitrogen cycling in the ocean: From genes to ecosystems and from the past to the future
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Temperature plays a crucial role in regulating sedimentary nitrogen removal and the associated N2O release Monday 7th @ 1010-1030, Multifunction Hall Ehui Tan* , State Key Laboratory of Marine Environmental Science, Xiamen University, China Wenbin Zou, State Key Laboratory of Marine Environmental Science, Xiamen University, China Jicong Xu, State Key Laboratory of Marine Environmental Science, Xiamen University, China Zhenzhen Zheng, State Key Laboratory of Marine Environmental Science, Xiamen University, China Ting-Chang Hsu, Earth System Science Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan Moge Du, State Key Laboratory of Marine Environmental Science, Xiamen University, China Li Tian, State Key Laboratory of Marine Environmental Science, Xiamen University, China Shuh-ji Kao, State Key Laboratory of Marine Environmental Science, Xiamen University, China Presenter Email: ehuitan@stu.xmu.edu.cn |
Denitrification and anaerobic ammonium oxidation (anammox) are two dominant processes for reactive nitrogen removal. In the context of global warming, temperature may serve as the primary forcing function to tune the microbial metabolism thus the community distribution, yet, how the community change and associated nitrogen removal pathways respond to warming remains a knowledge gap in prediction of nitrogen cycling and potential climate feedbacks. By using 15N isotope pairing technique, we measured the potential rates of sedimentary denitrification, anammox, and associated N2O production at a temperature gradient ranging from 1-35¡æ in various aquatic systems, including estuary, aquaculture pond, tidal flat and freshwater creek. The optima temperature and apparent activation energy for the denitrification were systematically and significantly higher than those for anammox. The N2O production rate was stimulated by temperature increase. While the N2O/N2 of denitrification exhibited a bimodal structure with higher values at both 1-15¡æ and 30-35¡æ. Combined our experimental results with global compilation of the existing data on in situ sedimentary denitrification, anammox, N2O release and N2O/N2 temperature dependence in various aquatic systems, we inferred that (1) denitrifying communities adapt to a higher and a wider temperature range, while the anammox bacteria were relatively cold-adapted; (2) N2O reductase was more easily to be suppressed than other enzymes participating the N2O production outside the habitable temperature. |
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