The earliest stages of ecosystem succession in high-elevation (5000 metres above sea level), recently deglaciated soils
Abstract
Global climate change has accelerated the pace of glacial retreat in high-latitude and high-elevation environments, exposing lands that remain devoid of vegetation for many years. The exposure of ‘new’ soil is particularly apparent at high elevations (5000 metres above sea level) in the Peruvian Andes, where extreme environmental conditions hinder plant colonization. Nonetheless, these seemingly barren soils contain a diverse microbial community; yet the biogeochemical role of micro-organisms at these extreme elevations remains unknown. Using biogeochemical and molecular techniques, we investigated the biological community structure and ecosystem functioning of the pre-plant stages of primary succession in soils along a high-Andean chronosequence. We found that recently glaciated soils were colonized by a diverse community of cyanobacteria during the first 4–5 years following glacial retreat. This significant increase in cyanobacterial diversity corresponded with equally dramatic increases in soil stability, heterotrophic microbial biomass, soil enzyme activity and the presence and abundance of photosynthetic and photoprotective pigments. Furthermore, we found that soil nitrogen-fixation rates increased almost two orders of magnitude during the first 4–5 years of succession, many years before the establishment of mosses, lichens or vascular plants. Carbon analyses (pyrolysis-gas chromatography/mass spectroscopy) of soil organic matter suggested that soil carbon along the chronosequence was of microbial origin. This indicates that inputs of nutrients and organic matter during early ecosystem development at these sites are dominated by microbial carbon and nitrogen fixation. Overall, our results indicate that photosynthetic and nitrogen-fixing bacteria play important roles in acquiring nutrients and facilitating ecological succession in soils near some of the highest elevation receding glaciers on the Earth.
Department
Soil Biogeochemistry and Microbial Ecology
Publication Date
8-26-2008
Journal Title
Proceedings of the Royal Society B Biological Sciences
Publisher
Royal Society
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
Schmidt S.K, Reed Sasha C, Nemergut Diana R, Stuart Grandy A, Cleveland Cory C, Weintraub Michael N, Hill Andrew W, Costello Elizabeth K, Meyer A.F, Neff J.C and Martin A.M 2008The earliest stages of ecosystem succession in high-elevation (5000 metres above sea level), recently deglaciated soilsProc. R. Soc. B.2752793–2802 http://doi.org/10.1098/rspb.2008.0808
Rights
© 2008 The Royal Society