Predictable feedbacks between warming, community structure and ecosystem functioning: a combined experimental and theoretical approach

全球变暖正在创造一个广泛改变的世界。越来越多的动物和植物不得不迁移，以跟上它们栖息地的变化，关键季节性事件的时间变化，繁殖季节和局部灭绝。新的证据表明，海洋和淡水生态系统的基本结构正在发生变化，可能最令人担忧的是，控制气候的关键全球循环已经改变。然而，在这些生态系统中维持生命的过程将如何应对未来的全球变暖尚不清楚。如果我们要能够预测生态系统将如何应对未来的变暖，并进一步实施管理战略，以保护这些生态系统的基本面，了解这些过程是至关重要的。这对科学家来说是一个重大挑战，因为生态系统本身就很复杂，它们对环境变化的反应往往是特殊的。我们将采取强有力的、多学科的方法来应对这一挑战。我们将开发数学模型，捕捉水生群落的结构和关键元素的循环及其与温度的关系。与此同时，我们将继续进行一项自2006年以来一直在进行的大规模实验，该实验涉及一系列复制的人工池塘的升温，以模拟未来全球变暖的影响。这些方法的结合将使我们能够确定生物学机制，将管理水生生态系统的反应，预计到世纪末的温度升高。从这项研究中得出的一般数学模型将为科学家提供关键的预测工具，用于研究全球变暖对生态系统的影响。而我们的实验操作将使我们能够测试或模拟预测，并提供变暖对整个水生生态系统影响的直接证据。生态学家通常将生态系统分解为结构（动物和植物）和功能（光合作用，分解）组件。结构部分通常侧重于植物和动物之间的数量，多样性和相互作用。而功能组件通常分析关键生物元素的循环。孤立地研究这些组成部分阻碍了理解生态系统如何应对环境变化（如变暖）的进展。使用上述实验系统，我们已经表明，变暖改变了水生生态系统的大小结构，降低了它们吸收二氧化碳的能力，并增加了它们释放的甲烷量。此外，我们的研究结果暗示了结构和功能成分之间可能的相互作用。确定水生生态系统的结构和功能之间的“联系”以及它们将如何应对变暖，将代表生态科学和理解未来全球变暖影响的重大进展。我们将联合收割机结合两个生态学理论，这两个理论都是成熟的，但尚未完全整合：生态代谢理论（MTE），它着眼于生态系统内的能量变化;和生态化学计量理论（EST），它着眼于生态系统内营养物质的平衡或“和谐”。利用这些理论，我们假设气候变暖将改变植物中必需元素的平衡，进而影响依赖动物的食物网结构。此外，我们预测营养循环（氮和磷）的不平衡，保持这些生态系统的完整性。我们将通过对营养物质和动植物的大小分布进行高分辨率的季节性测量来测试我们的想法，沿着我们实验系统中的光合作用和分解速率。

Global warming is creating an extensively modified world. An ever increasing number of animals and plants are having to migrate to keep up with changes to their habitats, alterations in the timing of key seasonal events e.g., breeding season and local extinction. New evidence suggests that the underlying structure of marine and freshwater ecosystems is changing, and potentially most alarmingly, key global cycles which control climate have been altered. However, how the processes that sustain life in these ecosystems will respond to future global warming are unknown. An understanding of these processes is crucial if we are to be able to predict how ecosystems will respond to warming in the future and furthermore implement management strategies to protect the fundamentals of these ecosystems. This represents a significant challenge for scientists because ecosystems are inherently complex and their response to environmental change can often be idiosyncratic. We will adopt a powerful, multi-disciplined approach to this challenge. We will develop mathematical models that capture the structure of aquatic communities and the cycling of key elements and their relationships with temperature. At the same time we will continue a large scale experiment which has been running since 2006 which involves the warming of a series of replicated artificial ponds to simulate the effects of future global warming. The combination of these approaches will allow us to determine the biological mechanisms that will govern the response of aquatic ecosystems to the elevated temperatures predicted for the end of the century. The general mathematical models that will come from this research will provide scientists will crucial predictive tools for the study of global warming on ecosystems. While our experimental manipulation will allow us to test or model predictions and provide direct evidence of the effects of warming on whole aquatic ecosystems. Ecologists typically break ecosystems down into structural (animals and plants) and functional (photosynthesis, decomposition) components. The structural component generally focuses on the numbers, diversity and interactions between plants and animals. While the functional component typically analyses the cycling of key biological elements. The study of these components in isolation has hindered progress in understanding how ecosystems will respond to environmental change e.g. warming. Using the described experimental system we have already shown that warming changes the size structure of aquatic ecosystems, reduces their ability to absorb carbon dioxide, and increases the amount of methane they release. Furthermore, our results have hinted towards the possible interactions between structural and functional components. Determining the 'links' between the structure and function of aquatic ecosystems and how they will respond to warming will represent a significant advance in the science of ecology and understanding the effects of future global warming. We will combine two theories in ecology that are both well established but not yet fully integrated: the Metabolic Theory of Ecology (MTE), which looks at the changes in energy within an ecosystem; and the Ecological Stoichiometric Theory (EST), which looks at the balance or 'harmony' of nutrients within an ecosystem. Using these theories, we hypothesise that warming will alter the balance of essential elements in plants which will go onto to affect the structure of the reliant animal food web. Further, we predict imbalances in the nutrient cycles (nitrogen and phosphorous) which maintain the integrity of these ecosystems. We will test our ideas by making high resolution seasonal measurements of nutrients and the size distribution of plants and animals, along with rates of photosynthesis and decomposition in our experimental systems.