Diatom assemblages in the surface water of the Indian Sector of the Antarctic Surface Water in summer of 1999/2000

• Main Authors: Yasushi Gomi, Haruko Umeda, Mitsuo Fukuchi, Akira Taniguchi
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: major water masses; i.e; the Subantarctic Surface Water and the Antarctic Surface Water; Antarctic; Indian; Southern Ocean; The Antarctic; Antarc*; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.505.7705; http://polaris.nipr.ac.jp/~penguin/polarbiosci/issues/pdf/2005-Gomi.pdf

Abstract: Abundance and species composition of diatom assemblages in surface water of the Indian Sector of the Antarctic Surface Water of the Southern Ocean were examined using samples gathered during the JARE-41 Cruise of the icebreaker Shirase in the summer of 1999/2000. On the westward leg (Leg 1), abundance of the diatom assemblage was geo-graphically rather uniform, while species composition was different geographically in mosa-ic manner. Dominant species on Leg 1 were the pennate Pseudo-nitzschia spp. and the cen-tric Dactyliosolen tenuijunctus, Chaetoceros sp. cf. dichaeta and Chaetoceros neglectus. On the eastward leg (Leg 2), abundance and species composition were different east and west of 60˚E. The community to the west was large in abundance and dominated by D. tenuijunctus, while that to the east was small and dominated by the pennate Fragilariopsis species. These diatom assemblages were grouped into four clusters on Leg 1 and three on Leg 2. Mosaic dis-tribution of the clusters was again evident on Leg 1, while rather simple east-west difference was the case on Leg 2. These geographical variations seem to be affected by local sea ice dynamics. key words: diatom assemblages, sea ice dynamics, Antarctic Surface Water, cluster analy-sis, spatial and temporal variations