Journal of Oceanography, Vol. 63 (No. 1), pp. 143-148, 2007Short Contribution
Katsuhisa Tanaka1*, Kazumaro Okamura1, Katsunori Kimoto1, Hiroshi Yagi2 and Masashi Kodama3
1Seikai National Fisheries Research Institute, Fisheries Research Agency, Taira, Nagasaki 851-2213, Japan
2Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552, Japan
3National Research Institute of Fisheries Science, Fisheries Research Agency, Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
(Received 19 May 2006; in revised form 7 August 2006; accepted 14 August 2006)
Abstract: CDB-P (phosphorus extractable by the citrate-dithionite-bicarbonate extraction procedure) was used as the indicator of bio-available inorganic P in the suspended and surface sediments in the inner part of Ariake Bay. The CDB-P pool of suspended and surface sediments in the tidal flat area was estimated to be 10 ton and 90 ton, respectively (total of 100 ton), which corresponds to 1.5 times the average dissolved inorganic phosphorus standing stock. During the summer periods of hypoxia, the CDB-P concentration in the surface sediments decreased with the decline of Eh, losing 43-47% of the CDB-P observed in April. These results suggest that the phosphorus dynamics have been affected by the decrease of resuspended sediment concentrations brought about by the reduction of the tidal currents and phosphate release from the surface sediments during frequently occurring summer hypoxia events.