Tackling microbial biodiversity to create ecological strategies relevant to soil carbon cycling

土壤是地球上第二大碳储存库。随着气候变化的持续，温度和降水的变化会影响土壤微生物，改变土壤中碳的循环，可能会减缓或加剧气候变化。科学家预测这种反馈的能力仍然很差，至少部分原因是土壤中微生物的生态和功能还没有得到很好的了解。此外，土壤碳是各种物质的混合物，从单糖到复杂的植物和微生物碎屑。这项研究将确定哪些微生物消耗关键类型的土壤碳。实验工作将考虑来自不同地区、气候和土壤类型的一系列土壤，以提供广泛适用的知识。该项目将验证这样一个假设，即描述分解和消耗土壤碳不同成分的微生物种群将改善土壤碳模型。生态系统对全球变化反馈的准确预测使决策者能够为未来做好准备，从而使社会受益。这项工作的其他更广泛的影响包括为西弗吉尼亚州农村和经济萧条地区的一百多名高中生提供体验式学习机会。该项目将为一个早期大学项目和STEM学院提供实践科学学习活动，以提高一个县中面临风险、经济上处于不利地位、得不到充分服务的青年的科学素养，该县只有不到10%的成年人拥有学士学位。一克土壤含有数千种微生物“物种”，使土壤成为地球上生物多样性最丰富的栖息地之一。也许是由于这种生物多样性，将微生物群落的组成与功能联系起来的斗争仍在继续。本研究将通过量化碳同化和生长的分类群特异性速率，将微生物的特性和系统发育与表型性状联系起来。土壤微生物的特性将被用来建立生态策略，将它们与土壤碳库联系起来，并促进生态系统建模。具体来说，该项目将测试以下假设：土壤异养生物可以分为吸收复杂植物碎片的初级分解者、吸收微生物坏死块的次级分解者、吸收不稳定溶解基质的被动消费者和消耗活微生物的掠食性微生物。利用系统发育工具，研究人员将确定这些生态策略是否在进化上保守，促进分类学和功能之间的联系。经验数据将用于细化和参数化微生物显式分解模型。这项工作使用了最先进的经验工具、系统发育学和生态学理论，将微生物群落提炼成一种货币，模型可以直接使用这种货币来增强我们对土壤碳循环的预测性理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Soil contains the second largest reservoir of carbon on earth. As climate change continues, altered temperature and precipitation can affect soil microorganisms and alter the cycling of carbon in soil, potentially mitigating or exacerbating climate change. The ability of scientists to predict this feedback remains poor, at least in part because the ecology and function of microorganisms in soil is not well understood. Further, soil carbon is a mixture of everything from simple sugars to complex plant and microbial debris. This research will determine which microorganisms consume key types of soil carbon. The experimental work will consider a range of soils from distinct regions, climates, and soil types to provide broadly applicable knowledge. The project will test the hypothesis that describing the populations of microorganisms that break down and consume different constituents of soil carbon will improve soil carbon models. Accurate predictions of ecosystem feedbacks to global change benefit society by allowing decision makers to prepare for the future. Additional broader impacts of this work include experiential learning opportunities for over one hundred high school students in a rural and economically depressed region of West Virginia. The project will contribute hands-on science learning activities to an early college program and STEM academy to improve scientific literacy with at-risk, economically disadvantaged, under-served youth in a county where fewer than 10% of adults have bachelor’s degrees.A single gram of soil contains thousands of microbial ‘species’, making soils among the most biodiverse habitats on earth. Perhaps due to this biodiversity, the struggle to connect composition with function in microbial communities persists. This research will connect microbial identity and phylogeny to phenotypic traits by quantifying taxon-specific rates of carbon assimilation and growth. The traits of soil microbes will be leveraged to build ecological strategies that connect them to soil carbon pools and facilitate ecosystem modeling. Specifically, the project will test the hypothesis that soil heterotrophs can be grouped as primary decomposers that assimilate complex plant debris, secondary decomposers that assimilate microbial necromass, passive consumers that assimilate labile dissolved substrates and predatory microbes that consume live microorganism. Using phylogenetic tools, the researchers will determine whether these ecological strategies are evolutionarily conserved, facilitating connections between taxonomy and function. The empirical data will be used to refine and parameterize a microbial-explicit decomposition model. This effort uses state-of-the-art empirical tools, phylogenetics, and ecological theory to distill microbial communities into a currency that models can directly use to enhance our predictive understanding of soil carbon cycling.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.