Carbon transformation in lakes

湖泊与它们所排放的土地有着千丝万缕的联系。从陆地上流失的有机碳以及其他营养物质和矿物质一旦到达湖泊就会被积极转化。例如，溶解在溪流中的有机碳（DOC）可以在湖中分解，产生二氧化碳，最终会损失到大气中。 然而，湖泊中碳转化的几个方面仍然知之甚少。例如，二氧化碳在湖泊表面的分布并不均匀，这意味着整个湖泊对湖泊CO2排放的贡献并不相等。我们建议使用新型测量技术来研究这种异质性，量化其程度、决定其大小的因素、其起源以及它是否对我们估计二氧化碳从湖泊表面逸出的速率很重要。在第二个项目中，我们建议研究如何水生杂草可以改变湖泊的化学和生物学释放一个显着的一部分，他们的光合作用DOC。在杂草覆盖持续增加的湖泊中，植物释放的有机物可以抵消并可能推翻通常在湖泊中分解的陆地有机碳的数量。 最后，我们将探讨一个尚未知道的DOC在湖泊中的部分，这里称为挥发性DOC。这部分是不测量的常规方法，我们的重点将是量化其重要性和生态作用的湖泊。

Lakes are inextricably linked to the land they drain. Organic carbon as well as other nutrients and minerals lost from the land are actively transformed once they reach lakes. For example, organic carbon dissolved (DOC) in streamwater can be decomposed within the lake, producing carbon dioxide that will eventually be lost to the atmosphere.  Yet, several aspects or carbon transformation in lakes remain poorly known. For example,  carbon dioxide is not homogeneously distributed over the surface of lakes, implying the at whole lake does not contribute equally to lake CO2 emission. We propose to study this heterogeneity using novel measurement techniques, to quantify its extent, the factors that determine its magnitude, its origin and whether it matters to our estimation of the rates at which CO2 escapes from the lakes'surface. In a second project, we propose to examine how aquatic weeds can alter the chemistry and biology of lakes by releasing a significant fraction of their photosynthesis as DOC. In lakes where weed cover continues to increase, such release of organic matter by plants can counterbalance and possibly overturn the amount of terrestrial organic carbon normally decomposed in the lake.   Lastly, we will explore an as yet unknown fraction of DOC in lakes, here called volatile DOC. This fraction is not measured by conventional methods and our focus will be to quantify its importance and ecological role in lakes.