Alpine soil carbon is vulnerable to rapid microbial decomposition under climate cooling

Abstract

As climate cooling is increasingly regarded as important natural variability of long-term global warming trends, there is a resurging interest in understanding its impact on biodiversity and ecosystem functioning. Here, we report a soil transplant experiment from lower to higher elevations in a Tibetan alpine grassland to simulate the impact of cooling on ecosystem community structure and function. Three years of cooling resulted in reduced plant productivity and microbial functional potential (for example, carbon respiration and nutrient cycling). Microbial genetic markers associated with chemically recalcitrant carbon decomposition remained unchanged despite a decrease in genes associated with chemically labile carbon decomposition. As a consequence, cooling-associated changes correlated with a decrease in soil organic carbon (SOC). Extrapolation of these results suggests that for every 1 °C decrease in annual average air temperature, 0.1 Pg (0.3%) of SOC would be lost from the Tibetan plateau. These results demonstrate that microbial feedbacks to cooling have the potential to differentially impact chemically labile and recalcitrant carbon turnover, which could lead to strong, adverse consequences on soil C storage. Our findings are alarming, considering the frequency of short-term cooling and its scale to disrupt ecosystems and biogeochemical cycling.

Microbial functional diversity: From concepts to applications

“…In the following sections, we provide two examples of community‐centered analyses of microbial functional diversity using ad hoc procedures. These two case studies are based on data from previous studies (Wu et al, ; Yue et al, ).…”

“…In this case study, we show how considering the diversity of functional genes variants at the community level can increase the correlation between estimated trait values and measured ecological processes (Figure a,b). We used data from previous studies (Wu et al, ; Yue et al, ) and analyzed the relationship between CH 4 emission in natural grassland and the diversity of mcrA and mmoX genes estimated at the community level using the methodology described hereafter. The mcrA gene encodes the alpha subunit of methyl coenzyme M reductase, involved in the final step of methanogenesis (Ma, Conrad, & Lu, ) while the mmoX gene encodes a methane monooxygenase, involved in the first step of methane oxidation by methanotrophs (Murreil, Gilbert, & McDonald, ).…”

Climate mediates continental scale patterns of stream microbial functional diversity

“…For instance, temperature has been shown to drive the latitudinal gradient in diversity of planktonic marine bacteria [8] or the continental scale gradients in diversity and assemblage composition of functional genes involved in denitrification and nitrogen fixation across forest soils [9,10]. Moreover, microbial functional gene diversity and composition can respond rapidly under warming and cooling scenarios, as demonstrated by experiments on soils [11,12]. These findings are framed in the metabolic theory of ecology [13], and thus higher mutation and speciation rates are expected towards warmer areas in accordance with the kinetics of biological processes.…”

“…In total, we detected 15, 289 functional genes linked to 88 functional gene families (Additional file 1: Table S1) included in these five functional categories (C, N, P, S and St). Microbial functional genes are ideal candidates for biodiversity projections under future climates as they meet two essential requirements of spatial distribution modelling [26], such as a high equilibrium with the environment because of their rapid response to changing conditions [11,12], and the relatively high dispersal capacity reported for microbes [27]. Moreover, literature indicates the utility in using elevational gradients for anticipating biodiversity responses to climate change over large geographical extents [28].…”

Progressive Microbial Community Networks with Incremental Organic Loading Rates Underlie Higher Anaerobic Digestion Performance

“…Archaeal community compositions were profiled by GeoChip, which is a microarray-based tool for profiling of microbial communities in a variety of environments (46)(47)(48)(49). The latest version of functional gene array, GeoChip 5.0 (60 K), was used.…”