Biogeochemistry and microbial community composition in sea ice and underlying seawater off East Antarctica during early spring

• Published in: Polar Biology
• Main Authors: Becquevort, S, Dumont, I, Tison, JL, Lannuzel, D, Sauvee, ML, Chou, L, Schoemann, V
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer-Verlag 2009
• Subjects: Environmental Sciences; Ecological applications; Ecosystem function; Antarctic; East Antarctica; Antarc*; Antarctica; Polar Biology; Sea ice
• Online Access: http://www.springerlink.com; https://doi.org/10.1007/s00300-009-0589-2; http://ecite.utas.edu.au/62628

Pack ice, brines and seawaters were sampled inOctober 2003 in the East Antarctic sector to investigate thestructure of the microbial communities (algae, bacteria andprotozoa) in relation to the associated physico-chemicalconditions (ice structure, temperature, salinity, inorganicnutrients, chlorophyll a and organic matter). Ice coverranged between 0.3 and 0.8 m, composed of granular andcolumnar ice. The brine volume fractions sharply increasedabove -4C in the bottom ice, coinciding with an importantincrease of algal biomass (up to 3.9 mg C l-1),suggesting a control of the algae growth by the spaceavailability at that period of time. Large accumulation ofNH4? and PO43- was observed in the bottom ice. The highpool of organic matter, especially of transparent exopolymericparticles, likely led to nutrients retention andlimitation of the protozoa grazing pressure, inducingtherefore an algal accumulation. In contrast, the heterotrophsdominated in the underlying seawaters.