Spatial heterogeneity provides organic matter refuges for soil microbial activity in the Patagonian steppe, Argentina

被引:48
作者
Gonzalez-Polo, Marina [1 ]
Austin, Amy T.
机构
[1] Consejo Nacl Invest Cient & Tecn, Fac Agron, Inst Invest Fisiol & Ecol Vinculadas Agr IFEVA, RA-1033 Buenos Aires, DF, Argentina
关键词
Microbial biomass; beta-Glucosidase activity; Mosses; Arid ecosystems; Extracellular enzymes; Biogeochemistry; Carbon cycling; Islands of fertility; Semi-arid steppe; Patagonia; Argentina; NITROGEN DYNAMICS; LITTER DECOMPOSITION; PULSES; PATTERNS; CARBON;
D O I
10.1016/j.soilbio.2009.03.008
中图分类号
S15 [土壤学];
学科分类号
0903 ; 090301 ;
摘要
In and and semi-arid ecosystems that are frequently classified as water limited, it is unclear how spatial and temporal variability of vegetation and climate could affect microbially-mediated soil processes. Our objective was to determine how aboveground spatial heterogeneity creates characteristic soil conditions that modulate microbial growth and activity in a semi-arid Patagonian steppe. In particular, we explored how micro-environmental and biogeochemical soil characteristics generated by the native vegetation could control soil beta-glucosidase activity. Both life-form (shrubs, grasses, mosses and bare soil) and season exerted strong controls on all measured abiotic (soil temperature and gravimetric soil water content, inorganic nitrogen, pH and total C and N) and biotic (microbial biomass C and beta-glucosidase activity) soil characteristics. Partial correlation between beta-glucosidase activity and extracellular organic C (EOC) was high across seasons (r = 0.5; P < 0.001) while soil water content did not correlate with soil enzymatic activity (r = 0.09: P > 0.05). We postulate that labile soil carbon rather than water availability functions as a principal limitation of microbial activity in this semi-arid ecosystem, and the distribution of this carbon is, in large part, determined by the patchy distribution of vegetation. (C) 2009 Elsevier Ltd. All rights reserved.
引用
收藏
页码:1348 / 1351
页数:4
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