Resource limitations on soil microbial activity in an Antarc

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TitleResource limitations on soil microbial activity in an Antarctic dry valleyAbstractAlthough Antarctic dry valley soils function under some of the harshest environmental conditions on the planet, there is significant biological activity concentrated in small areas in the landscape. Th ese productive areas serve as a source of C and N in organic matter redistributed to the surrounding biologically impoverished soils. We conducted a 3-yr replicated fi eld experiment involving soil amendment with C and N in simple (glucose and NH4Cl) and complex (glycine and lacustrine detritus) forms to evaluate the resource limitations on soil microbial activity in an Antarctic dry valley. The respiratory response for all substrates was slow, with a significant but weak response to NH4Cl, followed by a more widespread response to all substrates after 2 yr and in laboratory incubations conducted 3 yr after substrate addition. This response suggests that the soil microbial community is N limited and, when that constraint is alleviated, the organisms are able to access a pool of stored C that they could not metabolize before. The effects of added C and N substrates on respiration rates under laboratory conditions were more rapid and significant than the response rates measured in situ. Because the spatial constraints that had probably limited access to soil resources by microorganisms in the fi eld would have been removed in the laboratory incubation, this fi nding highlights the severe spatial constraints on access to resources in these soils. â"' Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All rights reserved.AcknowledgementsWe are grateful to Antarctica New Zealand for field work and logistic support in the 2002-2003, 2004-2005, and 2005-2006 field seasons (Project no. K052); A.D. Sparrow acknowledges support from the University of Canterbury, New Zealand, and the University of Nevada-Reno; E.G. Gregorich acknowledges the Research Branch of Agriculture and Agri-Food Canada; D.W. Hopkins acknowledges additional support from the Royal Society (of London), the TransAntarctic Association, the Carnegie Trust for the Universities of Scotland, the UK Natural Environment Research Council, and SCRI, which is supported in part by the Scottish Government; P.M. Novis acknowledges support from the Foundation for Research, Science and Technology (NZ). We also thank C. Galilee (NZ), P. St.-Georges (Canada), M. Tisch (NZ), and L. English (UK) for technical support and advice, and D.A. Wardle for helpful discussions during the design of the field experiment.

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1st AuthorSparrow, A.AuthorSparrow, A.Gregorich, E.Hopkins, D.Novis, P.Elberling, B.Greenfield, L.Year2011JournalSoil Science Society of America JournalVolume75Number6Pages2188-2197DOI10.2136/sssaj2010.0303URLhttps://www.scopus.com/inward/recor.....4faa27f5c345bd815464ff0ebKeywordsDry valleyEnvironmental conditionsIn-situLaboratory conditionsResource limitationsRespiration rateRespiratory responseResponse rateSmall areaSoil amendmentSoil microbial activitiesSoil microbial communitySoil resourcesSpatial constraintsWeak response, Amino acidsGlucoseLandformsMicroorganismsSoil conditionersSubstrates, Soils, bioactivitycarbonenvironmental conditionsincubationmicrobial activitynitrogenorganic matterresource scarcitysoil amendmentsoil microorganismvalley, Antarctica, rank5

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TypeArticleCitationSparrow, A., Gregorich, E., Hopkins, D., Novis, P., Elberling, B. and Greenfield, L. (2011) Resource limitations on soil microbial activity in an Antarctic dry valley. Soil Science Society of America Journal, 75(6): 2188-2197 doi:10.2136/sssaj2010.0303 IdentifierSparrow2011Relevancerank5