Castle Sarah C, Sullivan Benjamin W, Knelman Joseph, Hood Eran, Nemergut Diana R, Schmidt Steven K, Cleveland Cory C
Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, 59812, USA.
Department of Plant Pathology, University of Minnesota, 1991 Upper Buford Circle, 495 Borlaug, Saint Paul, MN, 55108, USA.
Oecologia. 2017 Nov;185(3):513-524. doi: 10.1007/s00442-017-3965-6. Epub 2017 Oct 5.
A dominant paradigm in ecology is that plants are limited by nitrogen (N) during primary succession. Whether generalizable patterns of nutrient limitation are also applicable to metabolically and phylogenetically diverse soil microbial communities, however, is not well understood. We investigated if measures of N and phosphorus (P) pools inform our understanding of the nutrient(s) most limiting to soil microbial community activities during primary succession. We evaluated soil biogeochemical properties and microbial processes using two complementary methodological approaches-a nutrient addition microcosm experiment and extracellular enzyme assays-to assess microbial nutrient limitation across three actively retreating glacial chronosequences. Microbial respiratory responses in the microcosm experiment provided evidence for N, P and N/P co-limitation at Easton Glacier, Washington, USA, Puca Glacier, Peru, and Mendenhall Glacier, Alaska, USA, respectively, and patterns of nutrient limitation generally reflected site-level differences in soil nutrient availability. The activities of three key extracellular enzymes known to vary with soil N and P availability developed in broadly similar ways among sites, increasing with succession and consistently correlating with changes in soil total N pools. Together, our findings demonstrate that during the earliest stages of soil development, microbial nutrient limitation and activity generally reflect soil nutrient supply, a result that is broadly consistent with biogeochemical theory.
生态学中的一个主流范式是,在原生演替过程中植物受到氮(N)的限制。然而,营养限制的一般模式是否也适用于代谢和系统发育多样的土壤微生物群落,目前还不太清楚。我们研究了氮和磷(P)库的测量是否有助于我们理解原生演替过程中对土壤微生物群落活动限制最大的养分。我们使用两种互补的方法——养分添加微观实验和胞外酶测定——来评估土壤生物地球化学性质和微生物过程,以评估美国华盛顿州伊斯顿冰川、秘鲁普卡冰川和美国阿拉斯加门登霍尔冰川三个正在退缩的冰川年代序列中的微生物养分限制。微观实验中的微生物呼吸反应分别为美国华盛顿州的伊斯顿冰川、秘鲁的普卡冰川和美国阿拉斯加的门登霍尔冰川的氮、磷和氮/磷共同限制提供了证据,养分限制模式总体上反映了土壤养分有效性的地点差异。已知随土壤氮和磷有效性而变化的三种关键胞外酶的活性在不同地点以大致相似的方式发展,随演替而增加,并始终与土壤总氮库的变化相关。我们的研究结果共同表明,在土壤发育的最早阶段,微生物养分限制和活性总体上反映了土壤养分供应,这一结果与生物地球化学理论大致一致。