Physiology and stable isotope ecology of moss growth for modeling spatial and temporal climatic signals

据预测，气候变化的影响在极地地区尤为严重。在以苔藓为主的栖息地广泛存在的北极，气候变暖和变湿可能导致永久冻土融化，苔藓生长增加，同时森林减少。我们现有的工作包括开发创新模型，利用有机物的稳定同位素组成来提供有关苔藓生长的信息。这项工作既包括在南极泥炭苔藓库中保存了数千年的苔藓，也包括通常生长在屋顶和道路上的耐干燥苔藓，这些苔藓在阵雨后会迅速激活。我们之前的工作表明，碳的稳定同位素组成为苔藓生长季节和气候变化的影响提供了可靠的指标。然而，与降水输入和水蒸气交换有关的其他自然存在的水中稳定同位素信号（例如水中的18O）迄今尚未被很好地定义为蒸发需求的标志。在这个提案中，我们将增加我们对苔藓生长动力学的理解，包括植物如何应对不同的蒸发条件，不同类型的苔藓如何生长，什么条件最适合从大气中固定二氧化碳并通过有机物合成生长。苔藓生理学的这些发展将与当地的天气条件结合在苔藓生长模型中，可以应用于大面积的植物生长时期预测。我们将进行实验室实验，利用同位素标记和不同温度、湿度和干燥制度下的生长反应，对苔藓的生长进行控制、监测和测量。我们将研究生长在一系列栖息地的苔藓物种，从潮湿的沼泽Sphagnums，到形成小山的Polytrichales，再到耐干燥的Syntrichia。在野外尺度上，同样的苔藓将在其自然环境中进行定期监测，测试实验确定的动态如何在生态相关环境中应用。实验室和野外测量的结合将首先使我们能够确定气候条件变化对苔藓有机质18O组成的控制。其次，将利用新开发的lift（激光诱导荧光瞬态）技术从几米远的距离进行遥感现场测量。通过在更大的空间尺度上了解苔藓生长动态和光合作用激活之间的联系，我们将建立一个基线，这将使遥感方法，如飞机和卫星的测量，在未来被用来监测苔藓的表现。

The impact of climate change is predicted to be particularly intense in polar regions. Warmer and wetter conditions in theArctic, where extensive moss dominated habitats are found, could lead to melting of permafrost and an increase in mossgrowth whilst forests decline. Our existing work has included developing innovative models which use the stable isotopecomposition of organic matter to provide information about moss growth. This work incorporated both moss preserved forthousands of years in Antarctic peat-moss banks, and desiccation-tolerant mosses that commonly grow on roofs and pathsand are rapidly activated following a rain shower. Our previous work has shown that the stable isotope composition ofcarbon provides a reliable indicator of moss growing season, and the impact of climate change. However other naturallyoccurringstable isotope signals in water (e.g 18O in water), associated with precipitation inputs and water vapour exchange, have until now been less well defined as markers of evaporative demand.In this proposal, we will increase our understanding of moss growth dynamics to include how plants respond to differentevaporative conditions, how different types of moss grow, what conditions are best for the fixation of carbon dioxide fromthe atmosphere and growth through the synthesis of organic matter. These developments in moss physiology will beintegrated with local weather conditions in models of moss growth that can be applied across large areas to predict periodsof plant growth. We will carry out laboratory experiments in which moss growth is manipulated, monitored and measured,using isotope labels and growth responses under different temperature, humidity and drying regimes. We will work on mossspecies that grow in a range of habitats from wet bog Sphagnums, through hummock forming Polytrichales to desiccationtolerant Syntrichia. At the field scale, the same mosses will be regularly monitored in their natural environment, testing howthe experimentally determined dynamics apply within an ecologically relevant setting. The combination of lab and fieldmeasurements will firstly allow us to determine the controls on moss organic matter 18O composition as climatic conditionsvary. Secondly, remote sensing field measurements will be made from a distance of several metres using newly developedLIFT (laser induced fluouresence transient) technology. By understanding the link between moss growth dynamics andphotosynthetic activation over this larger spatial scale we will establish a baseline that will allow remote sensingmethodologies, such as measurements from aeroplanes and satellites, to be used to monitor moss performance in the future.