Vegetation cover regulates the quantity,quality and temporal dynamics of dissolved organic carbon and nitrogen in Antarctic soils |
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Authors: | Paula Roberts Kevin K Newsham Richard D Bardgett John F Farrar David L Jones |
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Institution: | (1) School of the Environment and Natural Resources, Bangor University, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK;(2) British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK;(3) Department of Biological Sciences, Lancaster University, Lancaster, LA1 4YQ, UK;(4) School of Biological Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, UK |
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Abstract: | Populations of the two native Antarctic vascular plant species (Deschampsia antarctica and Colobanthus quitensis) have expanded rapidly in recent decades, yet little is known about the effects of these expansions on soil nutrient cycling.
We measured the concentrations of dissolved organic carbon (DOC) and nitrogen (DON), amino acids and inorganic N in soils
under these two vascular plant species, and under mosses and lichens, over a growing season at Signy Island in the maritime
Antarctic. We recorded higher concentrations of nitrate, total dissolved nitrogen, DOC, DON and free amino acids in soil under
D. antarctica and C. quitensis than in lichen or moss dominated soils. Each vegetation cover gave a unique profile of individual free amino acids in soil
solution. Significant interactions between soil type and time were found for free amino acid concentrations and C/N ratios,
indicating that vascular plants significantly change the temporal dynamics of N mineralization and immobilization. We conclude
that D. antarctica and C. quitensis exert a significant influence over C and N cycling in the maritime Antarctic, and that their recent population expansion
will have led to significant changes in the amount, type and rate of organic C and N cycling in soil. |
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Keywords: | Biogeochemistry Climate change Dissolved organic matter Population expansion Polar regions Signy Island |
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