Semeraro Sarah, Kipf Pascal, Le Bayon Renée-Claire, Rasmann Sergio
Laboratory of Functional Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
Front Microbiol. 2023 Apr 27;14:1152187. doi: 10.3389/fmicb.2023.1152187. eCollection 2023.
Organic matter (OM) decomposition has been shown to vary across ecosystems, suggesting that variation in local ecological conditions influences this process. A better understanding of the ecological factors driving OM decomposition rates will allow to better predict the effect of ecosystem changes on the carbon cycle. While temperature and humidity have been put forward as the main drivers of OM decomposition, the concomitant role of other ecosystem properties, such as soil physicochemical properties, and local microbial communities, remains to be investigated within large-scale ecological gradients. To address this gap, we measured the decomposition of a standardized OM source - green tea and rooibos tea - across 24 sites spread within a full factorial design including elevation and exposition, and across two distinct bioclimatic regions in the Swiss Alps. By analyzing OM decomposition via 19 climatic, edaphic or soil microbial activity-related variables, which strongly varied across sites, we identified solar radiation as the primary source of variation of both green and rooibos teabags decomposition rate. This study thus highlights that while most variables, such as temperature or humidity, as well as soil microbial activity, do impact decomposition process, in combination with the measured pedo-climatic niche, solar radiation, very likely by means of indirect effects, best captures variation in OM degradation. For instance, high solar radiation might favor photodegradation, in turn speeding up the decomposition activity of the local microbial communities. Future work should thus disentangle the synergistic effects of the unique local microbial community and solar radiation on OM decomposition across different habitats.
已有研究表明，生态系统中有机物（OM）的分解情况各不相同，这表明当地生态条件的差异会影响这一过程。更好地了解驱动OM分解速率的生态因素，将有助于更好地预测生态系统变化对碳循环的影响。虽然温度和湿度已被提出是OM分解的主要驱动因素，但其他生态系统属性（如土壤理化性质）和当地微生物群落的协同作用，在大规模生态梯度范围内仍有待研究。为了填补这一空白，我们在一个全因子设计中，测量了24个地点标准化OM源（绿茶和路易波士茶）的分解情况，该设计包括海拔和朝向，并跨越瑞士阿尔卑斯山的两个不同生物气候区域。通过分析与19个气候、土壤或土壤微生物活动相关的变量（这些变量在不同地点差异很大）对OM分解的影响，我们确定太阳辐射是绿茶和路易波士茶包分解速率变化的主要来源。因此，这项研究强调，虽然大多数变量（如温度或湿度）以及土壤微生物活动确实会影响分解过程，但结合测量的土壤气候生态位，太阳辐射很可能通过间接影响，最能体现OM降解的变化。例如，高太阳辐射可能有利于光降解，进而加速当地微生物群落的分解活动。因此，未来的工作应理清独特的当地微生物群落和太阳辐射对不同栖息地OM分解的协同作用。
