IIASA Young Scientists Summer Program: Testing the Role of Microbial Mechanisms in Moisture-Induced Soil Respiration Pulses Using a Theoretical Model

拟议的工作将在国际应用系统分析研究所进行，作为青年暑期科学家计划的一部分。在拟议的赠款期间（2012年夏季），参与者将与系统分析所的科学家合作开展一个关于微生物生态学的项目，知识价值：微生物群落控制着生物地球化学功能，因此，在某些条件下，微生物群落的组成（物种多样性）和功能（酶的产生）可以限制更大规模的过程。因此，在模型中描述这些微生物机制有可能改善对微生物地球化学通量的预测，并可以增加我们对最近新兴的微生物群落生态学领域的理解。YSSP的参与者建议使用Christina Kaiser开发的生态系统模型-明确模拟微生物群落-以确定最强烈控制微生物群落结构的降水模式，并描述干旱下酶产生的变化如何影响降雨恢复时的生物地球化学功能。虽然最近的几项实证研究已经描述了微生物群落和酶对降雨操作的反应，但目前还不清楚是什么控制着微生物动力学的这些变化，以及这些反应中是否存在可推广的模式。在这项工作中，她将能够测试关于微生物动力学如何影响大规模功能的几个假设，并使用现场数据进行验证，提出假设和机制，以在未来的经验和建模工作中建立。这项工作对1）改进地球化学循环的预测，从而预测气候变化的反馈和轨迹，2）将理论方法整合到微生物生态学中。首先，氮和碳化合物通过反硝化和分解等过程从土壤中排放出来。由于这些气体中有许多是温室气体，这些气体在空气中浓度的变化反过来会影响气候变化，如降雨和温度变化。微生物群落控制着土壤的生态地球化学功能，但目前大多数试图预测土壤生态地球化学动态的模型都不包括微生物群落。参与者？的工作将使用一种理论方法来解决微生物如何可能有助于功能，从而确定这种机制是否会增加地球化学模型的准确性。第二，理论建模具有很大的潜力，以提高我们对微生物群落结构和功能的控制的理解，但迄今为止在微生物生态学中尚未得到充分利用。学习理论方法，无论是在微生物生态学和其他领域，将允许YSSP参与者与其他微生物生态学家分享这些方法。在国外度过夏天之后，她计划通过日常互动以及公共和学术研讨会和培训来做到这一点。目前有很多人对这种方法感兴趣，其他人也渴望了解如何使用理论模型来补充经验工作。因此，这种接触不仅将促进女性科学家的职业生涯，而且还扩大了微生物生态学中使用的方法的范围，以改善模型预测并更好地理解微生物生态学理论。

The proposed work would take place at the International Institute for Applied Systems Analysis (IIASA) as part of the Young Summer Scientist Program (YSSP). During the proposed grant period (summer 2012), the participant would carry out a project on microbial ecology in collaboration with scientists at IIASA.Intellectual merit: Microbial communities control biogeochemical functions, and therefore composition (species diversity) and function (enzyme production) can constrain larger scale processes under certain conditions. Thus, descriptions of these microbial mechanisms in models have the potential to improve predictions of biogeochemical flux, and can increase our understanding of the recently emerging field of microbial community ecology. The YSSP participant proposes to use an ecosystem model developed by Christina Kaiser - that explicitly models microbial communities - to identify precipitation patterns that most strongly control microbial community structure, and describe how changes in enzyme production under drought can influence biogeochemical functions when rainfall returns. Although several recent empirical studies have described microbial community and enzyme responses to rainfall manipulations, it is unclear what controls these shifts in microbial dynamics, and whether there are generalizable patterns in these responses. In this work, she will be able to test several hypotheses about how microbial dynamics influence larger-scale functions, and validate it with field data, presenting hypotheses and mechanisms to build off of in future empirical and modeling work.Broader impacts: This work has implications for 1) improving predictions of biogeochemical cycles, and therefore predictions of climate change feedbacks and trajectories, and 2) for integrating theoretical approaches into microbial ecology. First, nitrogen and carbon compounds are emitted from the soil through processes like denitrification and decomposition. Since many of these gases are greenhouse gases, changes in the concentration of these gases in the air in turn affect climate changes, like rainfall and temperature shifts. Microbial communities control soil biogeochemical functions, but currently this biological compartment is excluded from most models attempting to predict biogeochemical dynamics. The participant?s work will use a theoretical approach to address how microbes might contribute to function, and therefore identify whether this mechanism will increase the accuracy of biogeochemical models. Second, theoretical modeling holds great potential for improving our understanding of controls on microbial community structure and function, but has been underutilized in microbial ecology thus far. Learning theoretical approaches, both in microbial ecology and in other fields, will allow the YSSP participant to share these approaches with other microbial ecologists. Following her summer abroad, the she plans to do this through day to day interactions and in workshops and trainings, both public and academic. There is currently a lot of interest in this approach, and others are eager to learn how theoretical models can be used to compliment empirical work. This exposure will therefore not only advance the career of a female scientist, but also broaden the scope of approaches used in microbial ecology to improve model predictions and better understand microbial ecology theory.