TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 62 (No. 2), pp. 185-196, 2006

Lethality of Increasing CO2 Levels on Deep-Sea Copepods in the Western North Pacific

Yuji Watanabe1,2*, Atsushi Yamaguchi3, Hiroshi Ishida1, Takashi Harimoto1, Shinya Suzuki1, Yoshio Sekido1, Tsutomu Ikeda3, Yoshihisa Shirayama4, Masayuki Mac Takahashi5, Takashi Ohsumi6 and Joji Ishizaka7

1The General Environmental Technos Co., Ltd., Azuchimachi, Chuo-ku, Osaka 541-0052, Japan
2Graduate School of Marine Science and Engineering, Nagasaki University, Bunkyo-machi, Nagasaki 852-8521, Japan
3Graduate School of Fisheries Sciences, Hokkaido University, Minato-cho, Hakodate 041-8611, Japan
4Field Science Education and Research Center, Kyoto University, Shirahama, Nishimuro, Wakayama 649-2211, Japan
5Graduate School of Kuroshio Sciences, Kochi University, Nangoku, Kochi 783-8502, Japan
6Research Institute of Innovative Technology for the Earth (RITE), Kizu, Soraku, Kyoto 619-0292, Japan
7Faculty of Fisheries, Nagasaki University, Bunkyo-machi, Nagasaki 852-8521, Japan

(Received 17 May 2004; in revised form 29 November 2005; accepted 30 November 2005)

Abstract: The first CO2 exposure experiments on several species of pelagic copepods inhabiting surface and deep layers in the western North Pacific were conducted. Living organisms were collected from two layers between the surface and 1,500 m between latitudes of 11 and 44°N, and they were exposed aboard ship to various pCO2 up to about 98,000 mμatm. Mortality of copepods from both shallow and deep layers in subarctic to subtropical regions increased with increasing pCO2 and exposure time. Deep-living copepods showed higher tolerance to pCO2 than shallow-living copepods. Furthermore, deep-living copepods from subarctic and transitional regions had higher tolerances than the subtropical copepods. The higher tolerances of the deep-living copepods from subarctic and transitional regions may be due to the adaptation to the natural pCO2 conditions in the subarctic ocean.

*Corresponding author E-mail: watanabe_yuji@kanso.co.jp

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