Seasonal periodicity of physical factors, inorganic nutrients and microalgae in Antarctic fellfields
Arnold, R.J.; Convey, P.; Hughes, K.A.; Wynn-williams, D.D.. 2003 Seasonal periodicity of physical factors, inorganic nutrients and microalgae in Antarctic fellfields. Polar Biology, 26 (6). 396-403. 10.1007/s00300-003-0503-2Full text not available from this repository. (Request a copy)
Over 15 months between January 1990 and March 1991, a range of physical, chemical and biological parameters was monitored regularly in fellfield soils of frost-sorted polygons at four sites on Signy Island (South Orkney Islands, maritime Antarctica). These included inorganic nutrients (orthophosphate, available nitrate and, over a more limited period, ammonia), chlorophyll a (as a proxy measure of microalgal biomass) and a range of potential cryoprotectant compounds. Transects across soil polygons revealed neither intrapolygon gradients in concentrations of inorganic nutrients or chlorophyll a nor significant interpolygon differences, in contrast with previous studies. Nitrate was present in much lower concentrations than phosphate, supporting evidence that it is a limiting nutrient in these fellfield ecosystems. Spring snowmelt, although a potential source of nutrient input, was not associated with increased concentrations of inorganic nutrients in the soil, probably through isolation of the soil from overlaying snow by a surface layer of ice. Soil micro-algae at the study sites must survive winter temperatures of at least -9degreesC, even when protected beneath up to 1 m of snow, and it has been proposed that they accumulate sugars and polyols as cryoprotectants. In support of this, concentrations of erythritol, glycerol, glucose, sucrose and trehalose in the soil (both absolute quantity and after correction for chlorophyll a concentration) increased as winter proceeded, suggesting that changes in sugar concentrations were due to accumulation within individual cells.
|Programmes:||BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Life at the Edge - Stresses and Thresholds|
|NORA Subject Terms:||Biology and Microbiology
Ecology and Environment
|Date made live:||05 Aug 2010 08:58|
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