Vertical flux of chlorophyll a under fast ice near Syowa Station, Antarctica, in austral summer, 1991/1992

• Main Authors: 小達 恒夫, 佐々木 洋, 福地 光男, Tsuneo Odate, Hiroshi Sasaki, Mitsuo Fukuchi
• Format: Report
• Language: English
• Published: 国立極地研究所 2004
• Subjects: 59(26); Austral; Syowa Station; Antarc*; Antarctica
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=9277; http://id.nii.ac.jp/1291/00009277/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=9277&item_no=1&attribute_id=18&file_no=1

1992年1月6日から2月6日の期間,南極昭和基地周辺の定着氷下の水深25あるいは30mにセジメントトラップを設置し,沈降する粒子を補足した.得られた試料を基に,クロロフィルa(Chl a)のフラックスを見積もり,夏季の植物プランクトン大増殖後の現存量低下に対する,沈降による除去の寄与率を評価した.セジメントトラップより上層の積算Chl a濃度は,1月中旬に最大に達した.Chl aフラックスは,Chl a濃度が最大に達した後に高くなった.上層のChl a濃度減少期における,1日当りの減少率は,8.71-10.4mg Chl a m-2 day-1 であった.この時,Chl aフラックスは,上層で起こったChl a減少率の3.6-4.0に過ぎなかった.このことは,植物プランクトンの沈降が,大増殖後にみられる現存量低下の大きな要因ではないことを示す. Sinking particles were collected using sediment traps, which were deployed at depths of 25 or 30m under fast ice near Syowa Station, Antarctica, from January 6 to February 6, 1992. Using the samples, fluxes of chlorophyll a (Chl a) were estimated and the contribution of algal sinking to the decrease of phytoplankton biomass after the summer bloom was evaluated. The Chl a concentration, integrated above the depths at which the sediment traps were deployed, reached a maximum in mid-January. The Chl a flux became high after the maximum of the concentration was recorded. In the Chl a decreasing phase, daily decreasing rates of the Chl a concentrations in the water columns were 8.71-10.4mg Chl a m-2 day-1 . During this period the Chl a fluxes accounted for only 3.6-4.0 of the decreasing rates. These observations imply that algal sinking is not the major process of phytoplankton biomass decrease after the summer bloom.