Zonal patterns of δ13C, δ15N and 210Po in the tropical and subtropical North Pacific

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Read Full Article (file size: 181242 bytes) Cited by GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L04609, doi:10.1029/2005GL025186, 2006 Zonal patterns of δ¹³C, δ¹⁵N and ²¹⁰Po in the tropical and subtropical North Pacific Min Chen Department of Oceanography, Xiamen University, Xiamen, China State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China Laodong Guo Department of Marine Science, University of Southern Mississippi, Stennis Space Center, Mississippi, USA Qiang Ma Department of Oceanography, Xiamen University, Xiamen, China Yusheng Qiu Department of Oceanography, Xiamen University, Xiamen, China State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China Run Zhang Department of Oceanography, Xiamen University, Xiamen, China E Lv Department of Oceanography, Xiamen University, Xiamen, China Yipu Huang Department of Oceanography, Xiamen University, Xiamen, China State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China Abstract Nitrogen fixation process may supply a significant fraction of bioavailable nitrogen to surface waters, increase the oceanic sequestration of atmospheric CO₂, and alter the distribution of geochemical parameters. We report a zonal pattern of δ¹⁵N and δ¹³C in particulate organic matter (POM), and ratios of particulate ²¹⁰Po to dissolved ²¹⁰Po along a transect through the subtropical and tropical North Pacific. Both ¹⁵N and ²¹⁰Po signals indicated an enhanced N₂ fixation in the northwestern subtropical North Pacific. The eastward decrease of N₂ fixation along this transect testified the role of aeolian Fe and P in controlling marine N₂ fixation. Associated with the zonal variations of ¹⁵N and ²¹⁰Po, the δ¹³C of suspended POM increased eastward, reflecting the decrease of anthropogenic CO₂ concentration in surface seawater from west to east in the study area. Our results highlight the need to examine more closely the mechanisms of possible longitudinal variation in N₂ fixation in the ocean and the role of aeolian Fe and P in controlling marine N₂ fixation and anthropogenic CO₂. Received 10 November 2005; accepted 5 January 2006; published 28 February 2006. Index Terms: 4870 Oceanography: Biological and Chemical: Stable isotopes (0454, 1041); 4860 Oceanography: Biological and Chemical: Radioactivity and radioisotopes; 4845 Oceanography: Biological and Chemical: Nutrients and nutrient cycling (0470, 1050); 4808 Oceanography: Biological and Chemical: Chemical tracers; 4805 Oceanography: Biological and Chemical: Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912). Read Full Article (file size: 181242 bytes) Cited by Citation: Chen, M., L. Guo, Q. Ma, Y. Qiu, R. Zhang, E. Lv, and Y. Huang (2006), Zonal patterns of δ¹³C, δ¹⁵N and ²¹⁰Po in the tropical and subtropical North Pacific, Geophys. Res. Lett., 33, L04609, doi:10.1029/2005GL025186. Copyright 2006 by the American Geophysical Union.

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