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General Session 3: Biological oceanography & global change |
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Influence of zooplankton grazing on the global marine nitrogen fixation by using structure equation model
GS3-04-S
Chu Chen* , State Key Laboratory of Marine Environmental Science
Nannan Wang, State Key Laboratory of Marine Environmental Science
Yawei Luo, State Key Laboratory of Marine Environmental Science
Presenter Email: chuchen@stu.xmu.edu.cn
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| Marine nitrogen fixation introduces new bio-available nitrogen to the ocean, strongly influencing the marine productivity and the structure and function of the marine ecosystem. Therefore, it is important to study the control mechanism of the marine nitrogen fixation and predict its response to climate change. Previous studies have shown that environmental factors such as light, temperature, and nutrients could influence nitrogen fixation, which is called “bottom-up control mechanism” in ecology; but it could not completely explain the observed distribution of marine nitrogen fixation. Based on the data of the global MNF rate, the abundance of cyanobacteria, the number of algae nifH gene copies and zooplankton abundance, this study uses structure equation model to preliminarily reveal that the zooplankton grazing (top-down control) and the bottom-up control jointly determines the distribution of the different diazotroph groups. This research will explain the controlling mechanisms of marine nitrogen fixation from new aspects, and improve our ability to predict the evolving marine nitrogen fixation in the future ocean. Key words: nitrogen fixation; SEM; zooplankton; bottom-up control; top-down control |
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