Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 5 2009 10.5194/bg-6-913-2009 http://www.biogeosciences.net/6/913/2009/ http://www.biogeosciences.net/6/913/2009/bg-6-913-2009.html http://www.biogeosciences.net/6/913/2009/bg-6-913-2009.pdf 913 922 2009-05-27 Phosphatase activity and organic phosphorus turnover on a high Arctic glacier M. Stibal marek.stibal@bristol.ac.uk A. M. Anesio C. J. D. Blues M. Tranter Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK Arctic glacier surfaces harbour abundant microbial communities consisting mainly of heterotrophic and photoautotrophic bacteria. The microbes must cope with low concentrations of nutrients and with the fact that both the dissolved and debris-bound nutrient pools are dominated by organic phases. Here we provide evidence that phosphorus (P) is deficient in the supraglacial environment on a Svalbard glacier, we quantify the enzymatic activity of phosphatases in the system and we estimate the contribution of the microbes to the cycling of the dominant organic P in the supraglacial environment. Incubation of cryoconite debris revealed significant phosphatase activity in the samples (19–67 nmol MUP g^−1 h^−1). It was inhibited by inorganic P during incubations and had its optimum at around 30°C. The phosphatase activity measured at near-in situ temperature and substrate concentration suggests that the available dissolved organic P can be turned over by microbes within ~3–11 h on the glacier surface. By contrast, the amount of potentially bioavailable debris-bound organic P is sufficient for a whole ablation season. However, it is apparent that some of this potentially bioavailable debris-bound P is not accessible to the microbes. Anesio, A. M., Hodson, A. 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