1. Introduction
Since 1965, surface chlorophyll a concentration has been routinely documented along cruise track in every JARE (Japanese Antarctic Research Expedition), which starts from Tokyo, Japan in November, reaches Syowa Station (69°00'S, 39°35'E), Antarctica, in late December to early January and returns to Tokyo in April. As the cruise track is usually fixed in time and space, the data show annual variation of phytoplankton standing stock in the Indian sector of the Southern Ocean. Historical reviews of these long-term observations are given by Fukuchi (1980, 1982) and Hirawake et al. (2005).
A surface water collection for phytoplankton species examination has
been carried out at the same time on board and water from several depths
has been also collected at some stations. This web site present phytoplankton
species composition on samples collected during the JARE cruises in austral
summer. We hope that these species composition datasets, together with
environmental parameters, i.e. water temperature, salinity and chlorophyll
a concentration, will contribute to our deeper understanding of the Southern
Ocean.
2. Materials and Method
Surface water was collected a few times a day, usually, from a surface
water monitoring system (see Fukuchi and Hattori, 1987) which pumps up
sea water from hull, about 8 m deep and deeper water was collected with
Niskin bottles attached to a CTD system. About 500 mL of water sample was
fixed with buffered formalin (2% v/v concentration). Water samples were
brought to a laboratory in Tokyo and settled in a counting chamber. Counting
was carried out with an inverted microscope.
For chlorophyll a measurements, surface seawater was sampled usually two or three times a day by pumping up through the hull. Subsurface water was collected with a Niskin bottle attached to the Rosette multi-sampler on a CTD or Van-Dorn bottle. Seawater samples of 200-300 ml were filtered onto a glass fiber filter (Whatman, GF/F). The filter was immediately soaked in N, N-dimethylformamide (Suzuki and Ishimaru, 1990), and pigments were extracted. The concentration of chlorophyll a and pheopigments were determined fluorometrically (Parsons et al., 1984) with a fluorometer (Turner Design, 10-AU). The fluorometer was calibrated against a chlorophyll a standard (Sigma Chemical Co.) using a spectrophotometer and the value of specific absorption coefficient obtained by Porra et al. (1989).
3. Scientists on board
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JARE-42 |
Shuhei Ban (Hokkaido University, present: University of Shiga Prefecture)
Waka Sato-Okoshi (Tohoku University)
Toru Hirawake (National Institute of Polar Research, present: Hokkaido University) |
|
JARE-43 |
Toru Hirawake (National Institute of Polar Research, present: Hokkaido University) |
|
JARE-44 |
Takehiro Masuzawa (Shizuoka University) |
|
JARE-45 |
Masako Iida (Hokkaido University)
Masahiro Matsuzaki (Hiroshima University)
Sakae Kudoh (National Institute of Polar Research) |
|
JARE-46 |
Akihisa S. Otsuki (National Institute of Polar Research) |
|
JARE-47 |
Masaki Honda (Central Research Institute of Electric Power Industry)
Ichinomiya
Saitoh |
4. Data Policy
The datasets contained may be used for publications or presentations with written permission from the National Institute of Polar Research (NIPR). Any inquiries should be addressed to
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Mitsuo FUKUCHI
9-10. Kaga 1-chome, Itabashi, Tokyo 173-8515, Japan
Phone: +81-3-3962-6031 Fax: +81-3-3962-4914
E-mail: fukuchi@nipr.ac.jp |
| or |
|
|
Toru HIRAWAKE
Graduate School of Fisheries Science, Hokkaido University
3-1-1 Minato-cho, Hakodate Hokkaido 041-8611, Japan
Phone/Fax: +81-138-40-8844 Fax: +81-138-435015
E-mail: hirawake@salmon.fish.hokudai.ac.jp |
5. Acknowledgments
We thank personnel of the JARE and officers and crew of the icebreaker
SHIRASE for their help on board. Thanks are also extended to the Marine
Biological Research Institute of Japan Co., Ltd. for analyses of phytoplankton
species composition.
This work was supported by Grant-in-Aid for Publication of Scientific
Research Results from the Japan Society for the Promotion of Science:
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No. 148119 in 2002 fiscal year for JARE-42 and -43 samples,
No. 158116 in 2003 fiscal year for JARE-44 samples,
No. 168116 in 2004 fiscal year for JARE-45 samples,
No. 178100 in 2005 fiscal year for JARE-46 samples and
No. 188098 in 2006 fiscal year for JARE-47 samples. |
6. References
Fukuchi, M., 1980. Phytoplankton chlorophyll stocks in the Antarctic Ocean. J. Oceanogr. Soc. Japan, 36: 73-84.
Fukuchi, M., 1982. Ichiji seisan, Dobutsu purankuton (Primary production, Zooplankton), pp. 11-55. Nankyoku no Kagaku, 7. Seibutsu (Science in Antarctica, 7. Biology), ed. by Natl Inst. Polar Res. Tokyo, Kokon Shoin.
Fukuchi, M. and H. Hattori, 1987. Surface water monitoring system installed on board the icebreaker Shirase. Proc. NIPR Symp. Polar Biol., 1: 47-55.
Hirawake, T., T. Odate and M. Fukuchi, 2005. Long-term variation of chl.a in the Southern Ocean during 1965-2002. Geophysical Research Letters, 32, L05606, doi:10.1029/2004GL021394.
Parsons, T. R., Maita, Y. and Lalli, C. M., 1984. A Manual of Chemical and Biological Methods for Seawater Analysis. Oxford, Pergamon Press, 173p.
Porra, R. J., Thompson, W. A. and Kriedemann, P. E., 1989. Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophyll a and b extracted with four different solvents: verification of the concentration of chlorophyll standards by atomic absorption spectroscopy. Biochim. Biophys. Acta, 975, 384-394.
Suzuki, R. and Ishimaru, T., 1990. An improved method for the determination of phytoplankton chlorophyll using N, N-dimethylformamide. J. Oceanogr. Soc. Jpn., 46, 190-194. |
