The biogeochemistry of meltwater habitats in the Darwin Glacier region (80 degrees S), Victoria Land, Antarctica

• Published in: Antarctic Science
• Main Authors: Webster-Brown, J, Gall, M, Gibson, J, Wood, S, Hawes, I
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge Univ Press 2010
• Subjects: Environmental Sciences; Ecological Applications; Landscape Ecology; Darwin Glacier; Diamond Hill; Grant Valley; Victoria Land; Wellman; Antarc*; Antarctic Science; Antarctica
• Online Access: https://doi.org/10.1017/S0954102010000787; http://ecite.utas.edu.au/66531

Meltwater habitats in the Darwin Glacier region, Victoria Land (808S), were sampled in December 2007 and January 2009 to characterize their microbial and metazoan ecology, nutrient status and geochemistry. Targeted areas included terrestrial ponds of the Grant Valley, Lake Wellman, Tentacle Ridgeand Diamond Hill, and supraglacial ponds and cryoconite holes of the lower Darwin Glacier. Geochemistry ranged from Na-Cl dominated terrestrial ponds to Na-HCO3 dominated, dilute supraglacial ponds and cryoconites. All showed the nitrate enrichment typical of inland ponds of Victoria Land (up to 13 g.l-1NO3-N), with some precipitating nitratine (NaNO3) salt. Elevated pH indicated ongoing photosynthetic processes. Benthic microbial mats were thin and poorly developed, dominated by oscillatoriacean cyanobacteria. Nitrogen-fixing genera were generally absent and diatoms were rare. A large (20 mm long)Cyanothece species was the most abundant cyanobacterium in the water and in sediments of the cryoconites. DNA finger-printing identified distinct differences in cyanobacterial and bacterial communitystructure between the cryoconites, terrestrial ponds and ponds on glacial margins. Eleven metazoan species were identified, with rotifers being the most abundant. Pond substrate (terrestrial rock, ice-cored moraine orsupraglacial ice) proved to be a more significant influence on biogeochemistry than other aspects of geography or climatic conditions.