Lauber Christian L, Metcalf Jessica L, Keepers Kyle, Ackermann Gail, Carter David O, Knight Rob
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA.
BioFrontiers Institute, University of Colorado, Boulder, Colorado, USA.
Appl Environ Microbiol. 2014 Aug;80(16):4920-9. doi: 10.1128/AEM.00957-14. Epub 2014 Jun 6.
Carrion decomposition is an ecologically important natural phenomenon influenced by a complex set of factors, including temperature, moisture, and the activity of microorganisms, invertebrates, and scavengers. The role of soil microbes as decomposers in this process is essential but not well understood and represents a knowledge gap in carrion ecology. To better define the role and sources of microbes in carrion decomposition, lab-reared mice were decomposed on either (i) soil with an intact microbial community or (ii) soil that was sterilized. We characterized the microbial community (16S rRNA gene for bacteria and archaea, and the 18S rRNA gene for fungi and microbial eukaryotes) for three body sites along with the underlying soil (i.e., gravesoils) at time intervals coinciding with visible changes in carrion morphology. Our results indicate that mice placed on soil with intact microbial communities reach advanced stages of decomposition 2 to 3 times faster than those placed on sterile soil. Microbial communities associated with skin and gravesoils of carrion in stages of active and advanced decay were significantly different between soil types (sterile versus untreated), suggesting that substrates on which carrion decompose may partially determine the microbial decomposer community. However, the source of the decomposer community (soil- versus carcass-associated microbes) was not clear in our data set, suggesting that greater sequencing depth needs to be employed to identify the origin of the decomposer communities in carrion decomposition. Overall, our data show that soil microbial communities have a significant impact on the rate at which carrion decomposes and have important implications for understanding carrion ecology.
腐肉分解是一种具有重要生态意义的自然现象，受一系列复杂因素影响，包括温度、湿度以及微生物、无脊椎动物和食腐动物的活动。土壤微生物作为这一过程中的分解者，其作用至关重要，但尚未得到充分了解，这代表了腐肉生态学中的一个知识空白。为了更好地界定微生物在腐肉分解中的作用和来源，将实验室饲养的小鼠置于以下两种土壤上进行分解：（i）具有完整微生物群落的土壤，或（ii）经过灭菌处理的土壤。我们在与腐肉形态明显变化一致的时间间隔，对三个身体部位以及下层土壤（即墓土）的微生物群落进行了特征分析（细菌和古菌的16S rRNA基因，真菌和微生物真核生物的18S rRNA基因）。我们的结果表明，置于具有完整微生物群落土壤上的小鼠比置于无菌土壤上的小鼠达到分解高级阶段的速度快2至3倍。在活跃腐烂和高级腐烂阶段，与腐肉皮肤和墓土相关的微生物群落在不同土壤类型（无菌与未处理）之间存在显著差异，这表明腐肉分解所依赖的底物可能部分决定了微生物分解者群落。然而，在我们的数据集中分解者群落的来源（与土壤相关还是与尸体相关的微生物）并不明确，这表明需要采用更大的测序深度来确定腐肉分解中分解者群落的来源。总体而言，我们的数据表明土壤微生物群落对腐肉分解的速度有显著影响，并对理解腐肉生态学具有重要意义。
