Effects of Long-Term Soil Warming on Microbial Yield, Acquisition, and Stress Traits at Harvard Forest 2014

Soil microbial traits drive ecosystem functions. This relationship can explain why microbial functional diversity is typically positively correlated with ecosystem function. However, microbial adaptation to climate change related warming stress can shift microbial traits with direct implications for carbon cycling in the soil. Here, we investigated how long-term warming affects the relationship between microbial trait diversity and ecosystem function. Soils were sampled after 24 years of +5\degree C warming alongside unheated control soils from the Harvard Forest Long-Term Ecological Research site. Ecosystem function was estimated from six different enzyme activities and microbial biomass. This data was coupled with metatranscriptomics sequencing, where reads were assigned to yield, acquisition, or stress trait categories. We found that in organic horizon soils, warming decreased the richness of acquisition-related traits. In the mineral soils, we observed that heated soils exhibited a negative relationship with the richness of acquisition related traits. These results suggest that the microbial communities exposed to long-term warming is shifting away from a resource acquisition life history strategy.

土壤微生物性状驱动生态系统功能。这种关系可解释为何微生物功能多样性通常与生态系统功能呈正相关。然而，微生物对气候变化相关的变暖胁迫的适应会改变其性状，这对土壤碳循环具有直接影响。本研究旨在探究长期变暖如何影响微生物性状多样性与生态系统功能之间的关系。土壤样本取自哈佛森林长期生态研究站（Harvard Forest Long-Term Ecological Research site）经过24年+5°C升温处理的地块及未加热对照地块。生态系统功能通过六种不同酶活性及微生物生物量进行评估。该数据与宏转录组测序（metatranscriptomics sequencing）数据相结合，测序读段被归类为产量、获取或胁迫性状类别。研究发现，在有机层土壤中，变暖降低了获取相关性状的丰富度。在矿质土壤中，加热处理的土壤与获取相关性状丰富度呈负相关关系。这些结果表明，长期暴露于变暖环境中的微生物群落正逐渐偏离资源获取型生活史策略。