Biological Regulation of Subsoil C-cycling under Field Conditions

野外条件下底土碳循环的生物调控

• 批准号: 233441257
• 负责人: Professorin Dr. Ellen Kandeler
• 金额: --
• 依托单位: Fachgebiet Bodenbiologie (310b)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/233441257?language=en
• 关键词: Biological; Regulation; Subsoil; cycling; under

Two soil transfer experiments done in the first phase provided evidence of depth specific carbon incorporation of either cellulose or root derived carbon into different groups of soil microorganisms. Fungal abundance was restricted in subsoils, but fungi incorporated more carbon than bacteria in both surface and subsoils. Consequently, we need to better understand the release of carbon from specific groups of soil microorganisms as well as the transport of microbial residues within the soil profile to adequately model microbially mediated C pathways in soil profiles. Data from the two joint experiments (observatories and DOC injection) will be combined with the exposure of labelled bacteria and fungi at different depths (see Task 1 and 2), making it possible to characterize group specific turnover times as well as transport of microbial residues at two different levels of resolution (temporal scale: either weeks or years, spatial scale: centimeters or meters). Since we have learned that fungal life in subsoils is restricted and that transfer of deeper subsoil into shallower subsoil stimulates fungal abundance, we need to explore further the dynamics and drivers of fungal communities in subsoils. Using next generation sequencing of fungal internal transcribed spacers (ITS) we will define fungal guilds based on their main source of C; saprotrophic fungi are those that gain C from dead organic material, and root-associated fungi are those that gain C directly from their host plant. We will relate fungal key players to the production of specific enzymes and identify them as either saprotrophs (producing hydrolytic and oxidative enzymes) or decomposers (producing oxidative enzymes only). In the context of the research unit, our data will clarify the importance of bacterially and fungally driven stabilisation of organic substances in subsoils and provide a better understanding of long-term carbon storage in forest ecosystems.

在第一阶段进行的两个土壤转移实验提供了纤维素或根源碳进入不同土壤微生物群的深度特定碳结合的证据。真菌丰度在底土中受到限制，但真菌在表层和底土中都比细菌吸收更多的碳。因此，我们需要更好地了解特定土壤微生物群体的碳释放以及土壤剖面中微生物残留物的运输，以充分模拟土壤剖面中微生物介导的碳途径。来自两个联合实验（观察站和DOC注射）的数据将与在不同深度暴露的标记细菌和真菌（见任务1和2）相结合，从而可以在两种不同的分辨率水平（时间尺度：周或年，空间尺度：厘米或米）上表征群体特定的周转时间以及微生物残留物的运输。由于我们已经了解到真菌在底土中的生命是有限的，并且深层底土向浅层底土的转移刺激了真菌的丰度，我们需要进一步探索底土真菌群落的动态和驱动因素。利用真菌内部转录间隔序列（ITS）的下一代测序，我们将根据真菌的主要C来源来定义真菌行会；腐养真菌是从死亡的有机物质中获取C的，而根相关真菌是直接从宿主植物中获取C的。我们将把真菌与特定酶的生产联系起来，并将它们确定为腐生菌（生产水解酶和氧化酶）或分解者（仅生产氧化酶）。在研究单位的背景下，我们的数据将阐明细菌和真菌驱动的地下土壤中有机物质稳定的重要性，并提供对森林生态系统长期碳储存的更好理解。