Developing a trait-based framework for predicting soil microbial community response to extreme events

气候变化已经影响到地球的生态系统。虽然大多数人在考虑气候变化时都会想到平均气温的上升，但近年来的情况表明，即使在英国，洪水和干旱也变得越来越普遍，它们对许多动植物的影响是毁灭性的。然而，虽然这些极端天气事件的地面影响可以清楚地看到，但地下的大屠杀仍然隐藏在我们的眼睛之外。土壤中居住着数百万种微小生物：少量土壤可以包含数十亿个细菌细胞，来自数万种细菌物种，以及数百种真菌物种。生活在土壤中的微生物的生物量甚至可以超过生活在土壤中的更大的动物的生物量！但这些生物也不能幸免于干旱和洪水的后果。特别是细菌，它们不能很好地科普干旱：它们的细胞壁是半透性的，干旱会导致它们的细胞萎缩和死亡。再润湿后，它们会膨胀并爆炸。真菌的许多功能与土壤中的细菌相同，它们比细菌更能科普极端干旱：它们的细胞壁更坚固，生长速度比细菌慢，这使它们更有可能抵抗干旱等压力。相比之下，洪水导致土壤中的低氧条件，这可能比真菌更有利于细菌，而细菌是水生生物。然而，细菌和真菌种群本身由数千种物种组成，这些物种对干旱和洪水的反应可能不同。但是，我们对细菌和真菌种群如何受到这些极端天气事件的影响知之甚少。虽然土壤细菌和真菌隐藏在我们的脚下，但它们对地球生态系统的功能至关重要：它们分解有机物质，从而释放植物生长的养分。这些是支持陆地上所有生态系统的过程，包括生产我们食物的农业系统。然而，当细菌和真菌种群受到极端天气事件的影响时，它们所执行的过程也会受到影响，这些过程的变化反过来会影响地上植物和动物。因此，这些看不见的生物有可能使我们肉眼可见的极端天气事件的后果变得更糟。然而，目前，我们还不知道如何预测细菌和真菌种群的变化将如何导致它们所执行的过程的变化。在这个项目中，我们将调查生活在土壤中的细菌和真菌种群如何受到极端天气事件的影响，我们的目标是确定对此负责的特征。例如，一些细菌可以形成孢子，从而在各种压力下生存下来，但可能还有许多其他特性可以让细菌和真菌科普极端天气事件。我们将使用一个独特的实验，在这个实验中，我们将来自欧洲不同气候的土壤不仅经受干旱和洪水，而且经受热浪和冰冻，我们将把这个实验与最先进的DNA测序和生物信息学相结合，以量化细菌和真菌的反应，并推断出造成这种反应的特征。此外，我们将测量这些生物体执行的过程如何随着这些极端天气事件而变化。这项工作将导致土壤细菌和真菌对极端天气事件的反应的基础知识，并在一个框架，使我们能够预测土壤及其功能将如何应对极端天气事件。这一知识对于使地球生态系统适应气候变化至关重要。

Climate change is already affecting the Earth's ecosystems. While most people think of increasing average temperatures when they think about climate change, recent years have shown us that even in the UK flooding and droughts are becoming more common, their effects devastating for many animals and plants. However, while the aboveground effects of these extreme weather events can clearly be seen, the carnage belowground remains hidden from our eyes. The soil is inhabited by millions of tiny creatures: a handful of soil can contain billions of bacterial cells, from tens of thousands of bacterial species, as well as hundreds of fungal species. The biomass of the microorganisms that live in the soil can even outweigh the biomass of the much larger animals that live on it! But these creatures are not immune to the consequences of drought and flooding. Especially bacteria don't cope very well with drought: they have semi-permeable cell walls and drought causes their cells to shrivel and die. After rewetting, they swell up and explode. Fungi, which perform many of the same functions as bacteria in the soil, are better able to cope with extreme drought than bacteria: they have stronger cell walls and are slower-growing than bacteria, which makes them more likely to resist stresses like drought. Flooding, in contrast, causes low oxygen conditions in the soil, which might be more favourable for bacteria, which are aquatic organisms, than for fungi. However, bacterial and fungal populations themselves consist of thousands of species, and these species might differ in their response to drought and flooding. But, we have very little idea of how bacterial and fungal populations are affected by these extreme weather events. Although soil bacteria and fungi are hidden beneath our feet, they perform functions that are crucial for the functioning of the Earth's ecosystems: they decompose organic matter, thereby releasing nutrients for plant growth. These are the processes that support all ecosystems on land, including the agricultural systems that produce our food. However, when bacterial and fungal populations are affected by extreme weather events, so will the processes that they perform, and these changes in processes can in turn affect aboveground plants and animals. So, these unseen organisms have the potential to make the consequences of extreme weather events that we can see with our eyes even worse. However, at present, we don't know how we can predict how changes in bacterial and fungal populations will result in a change in the processes that they perform.In this project, we will investigate how bacterial and fungal populations that live in the soil are affected by extreme weather events, and we aim to identify the traits that are responsible for this. For example, some groups of bacteria can form spores and thus survive a wide range of stresses, but there might be many other traits that can allow bacteria and fungi to cope with extreme weather events. We will use a unique experiment in which we subject soils from different climates across Europe not just to drought and flooding, but also to heatwave and freezing, and we will combine this with state-of-the-art DNA sequencing and bioinformatics to quantify bacterial and fungal response and to infer the traits responsible for this. In addition, we will measure how the processes that these organisms perform change with these extreme weather events. This work will result in fundamental knowledge on soil bacterial and fungal response to extreme weather events, and in a framework that allows us to predict how soils and their functioning will respond to extreme weather events. This knowledge is of the highest importance for adapting the Earth's ecosystems to climate change.