Seasonal progression of diatom assemblages in surface waters of Ryder Bay, Antarctica

• Published in: Polar Biology
• Main Authors: Annett, Amber L., Carson, Damien, Crosta, Xavier, Clarke, Andrew, Ganeshram, Raja S.
• Other Authors: Grant Institute, University of Edinburgh, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), British Antarctic Survey (BAS), Natural Environment Research Council (NERC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: Proboscia inermis; Coastal Antarctic; Sea-ice; Diatoms; Phytoplankton; Seasonality; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Austral; Adelaide Island; Ryder; Ryder Bay; Antarc*; Antarctica; Polar Biology; Sea ice
• Online Access: https://hal.archives-ouvertes.fr/hal-02105660; https://doi.org/10.1007/s00300-009-0681-7

International audience Phytoplankton assemblages from seasonally sea-ice covered Ryder Bay (Adelaide Island, Antarctica) were studied over three austral summers (2004-2007), to link sea-ice variability and environmental conditions with algal speciation. Typical of near-shore Antarctic waters, biomass was dominated by large diatoms, although the prymnesiophyte Phaeocystis antarctica was numerically dominant. Although there was considerable interannual variability between main diatom species, high biomass of certain species or species groups corresponded consistently to certain phases of seasonal progression. We present the first documentation of an extensive bloom of the late-season diatom Proboscia inermis in February 2006, accounting for over 90% of diatom biomass. At this time, water column stratification and nutrient drawdown were high relative to other periods of the study, although carbon export was relatively low. Melt water flux in this region promotes well-stratified surface waters and high chlorophyll levels, but not necessarily concurrent increases in export production relative to seasons with lower freshwater inputs.