The biogeochemistry of meltwater habitats in the Darwin Glacier region (80°S), Victoria Land, Antarctica
The biogeochemistry of meltwater habitats in the Darwin Glacier region (80°S), Victoria Land, Antarctica
复制标题
南极洲维多利亚地达尔文冰川地区（南 80°）融水栖息地的生物地球化学
作者：
J. Webster;M. Gall;J. Gibson;S. Wood;I. Hawes
摘要2007年12月和2009年1月，对维多利亚地（80°S）达尔文冰川区的融水生境进行了取样，以表征其微生物和后生动物生态、营养状况和地球化学。目标地区包括格兰特谷、韦尔曼湖、触手岭和钻石山的陆地池塘，以及达尔文冰川下游的冰上池塘和冰尘洞。地球化学范围从Na-Cl为主的陆地池塘Na-HCO 3为主，稀释冰上池塘和cryoconites。所有显示硝酸盐富集典型的内陆池塘的维多利亚土地（高达13克升-1 NO3-N），与一些沉淀硝酸盐（NaNO 3）盐。pH值升高表明正在进行的光合作用过程。底栖微生物垫薄，发育不良，主要是蓝藻。固氮属一般缺席和硅藻是罕见的。一个大的（20 μm长）蓝杆藻种是最丰富的蓝藻在水和沉积物中的寒生。DNA指纹识别的cryoconites，陆地池塘和池塘冰川边缘的蓝藻和细菌群落结构之间的显着差异。鉴定出11种后生动物，其中轮虫最为丰富。池塘底质（陆地岩石，冰芯冰碛或冰上冰）被证明是一个更重要的影响比其他方面的地理或气候条件的地球化学。
Abstract Meltwater habitats in the Darwin Glacier region, Victoria Land (80°S), 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 Ridge and 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-1 NO3-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 μm 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 community structure 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 or supraglacial ice) proved to be a more significant influence on biogeochemistry than other aspects of geography or climatic conditions.