Articles |Volume 12, issue 23https://doi.org/10.5194/bg-12-6931-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-12-6931-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
|
04 Dec 2015
Research article |
|
04 Dec 2015Why isTrichodesmium abundant in the Kuroshio?
T. Shiozaki,S. Takeda,S. Itoh,T. Kodama,X. Liu,F. Hashihama,andK. Furuya Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
Faculty of Fisheries, Nagasaki University, Nagasaki, 852-8521, Japan
Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
Japan Sea National Fisheries Research Institute, Fisheries Research Agency, Niigata, 951-8121, Japan
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China
Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Tokyo, 108-8477, Japan
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
Abstract. The genusTrichodesmium is recognized as an abundant and major diazotroph in the Kuroshio, but the reason for this remains unclear. The present study investigated the abundance ofTrichodesmium spp. and nitrogen fixation together with concentrations of dissolved iron and phosphate in the Kuroshio and its marginal seas. We performed the observations near the Miyako Islands, which form part of the Ryukyu Islands, situated along the Kuroshio, since our satellite analysis suggested that material transport could occur from the islands to the Kuroshio.Trichodesmium spp. bloomed (> 20 000 filaments L−1) near the Miyako Islands, abundance was high in the Kuroshio and the Kuroshio bifurcation region of the East China Sea, but was low in the Philippine Sea. The abundance ofTrichodesmium spp. was significantly correlated with the total nitrogen fixation activity. The surface concentrations of dissolved iron (0.19–0.89 nM) and phosphate (< 3–36 nM) were similar for all of the study areas, indicating that the nutrient distribution could not explain the spatial differences inTrichodesmium spp. abundance and nitrogen fixation. Numerical particle-tracking experiments simulated the transportation of water around the Ryukyu Islands to the Kuroshio. Our results indicate thatTrichodesmium growing around the Ryukyu Islands could be advected into the Kuroshio.
How to cite. Shiozaki, T., Takeda, S., Itoh, S., Kodama, T., Liu, X., Hashihama, F., and Furuya, K.: Why isTrichodesmium abundant in the Kuroshio?, Biogeosciences, 12, 6931–6943, https://doi.org/10.5194/bg-12-6931-2015, 2015.
Received: 13 Jun 2015 –Discussion started: 16 Jul 2015 –Revised: 17 Nov 2015 –Accepted: 22 Nov 2015 –Published: 04 Dec 2015
