Quantifying the biodiversity threshold for peatland carbon service delivery

泥炭苔藓泥炭地固碳，提供重要的气候调节服务。用于这些沼泽植物生长的碳主要来自两个来源。首先是大气中的二氧化碳。另一种是次表层植物物质分解释放的甲烷。甲烷本身不能用于光合作用。然而，当泥炭地表面变得特别潮湿时，已发现某些种类的甲烷喂养细菌存在于泥炭地表面。它们被发现生活在泥炭苔藓的组织中。这些“甲烷营养”细菌以泥炭地释放的甲烷为食。当他们这样做的时候，他们会产生二氧化碳作为一种双产品。由于它们生活在泥炭藓的组织中，它们产生的二氧化碳为泥炭藓的光合作用提供了额外的来源。目前尚不清楚的是，形成Sphnagum苔藓的碳有多少是从大气中吸收的，有多少是从泥炭地亚表层缺氧腐烂释放的甲烷中回收的。此外，了解表面湿度是否存在某个阈值是至关重要的，超过这个阈值，甲烷营养细菌开始或停止工作。该项目将使用四种类型的地球化学和物理沉积物分析的新组合来证明循环甲烷和大气二氧化碳在泥炭地碳固定中的相对重要性。我们将测试泥炭地表面湿度过去的变化是否与气候变化有关，是否创造了有利于甲烷细菌种群的条件。我们将测试这些细菌的存在是否会导致过去碳封存的变化，从而帮助理解它们可能如何应对目前的变化。这项工作将直接影响泥炭地应该重新湿地的程度。那么，我们希望回答是否要淋湿的问题？！

Sphagnum moss peatlands sequester carbon, providing a vital climate regulation service. The carbon that is used in the growth of these bog plants can come from two main sources. The first is atmospheric carbon dioxide. The other is from methane released by the decomposition of plant material in the sub-surface layers. Methane itself can not be used for photosynthesis. However, certain species of methane-feeding bacteria have been found to exist in peatland surfaces when those surfaces become particularly wet. They have been found to live in the tissues of Sphagnum mosses. These "methanotrophic" bacteria feed on the methane released from the peatland. As they do so, they create carbon dioxide as a bi-product. As they live in the Sphagnum tissues, the carbon dioxide that they create provides an additional source for Sphagnum photosynthesis. What is still unclear is how much of the carbon that becomes Sphnagum moss is drawn-down from the atmosphere and how much is recycled from methane released from anoxic decay in the sub-surface layers of the peatlands. Furthermore, it is vitally important to understand whether there is a certain threshold of surface wetness beyond which the methanotrophic bacteria start or stop doing their work.This project will demonstrate the relative importance of recycled methane and atmospheric CO2 in peatland carbon sequestration using a novel combination of four types of geochemical and physical sediment analyses. We will test whether past changes in peatland surface wetness, themselves linked to climate change, created conditions favourable for populations of methane-feeding bacteria. We will test whether the presence of those bacteria led to changes in carbon sequestration in the past, thereby helping understanding of how they might respond to changes in present.The work will have direct implications on just how far peatlands should be re-wetted. We hope, then, to answer the question of whether to wet or not to wet?!