Sedimentation of microalgae under the Antarctic fast ice in summer

• Main Authors: Hiroshi Sasaki, Takao Hoshiai
• Format: Report
• Language: English
• Published: Faculty of Agriculture, Tohoku University 1986
• Subjects: Antarctic; Austral; Syowa Station; The Antarctic; Antarc*; ice algae; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1875; http://id.nii.ac.jp/1291/00001875/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1875&item_no=1&attribute_id=18&file_no=1

The development of ice algae and phytoplankton, and their sedimentation processes were studied in the Antarctic ice-covered sea near Syowa Station in the austral spring and summer 1982-83. The chlorophyll α concentration of ice algae at the bottom ice markedly increased from September to December, reaching the maximum of >300mg・m^<-3> in the ice algal bloom, and decreased abruptly in January. Phytoplankton chlorophyll α levels in the water column under the ice were low until December but increased in January (>2mg・m^<-3>). Changes in sedimentation rates of sinking particles showed that large ice algal aggregates which were the major component during the ice algal bloom detached from the undersurface of the ice and sank down to the sea floor. On the contrary, during the phytoplankton bloom, solitary diatoms, chain-forming diatoms and small algal aggregates constituted a significant portion of sinking particles. Sedimentation fluxes of fecal pellets of herbivorous zooplankton including diatoms decreased during the ice algal bloom. The microalgae have a high probability of reaching the bottom during the summer growing season and become and important food for benthic organisms.