The Origins and Biological Utilization of Dissolved Organic Carbon in Riverine Saltmarsh Estuaries

河流盐沼河口溶解有机质的循环具有明显的非保守性。在马萨诸塞州北部的帕克河-普勒姆岛海湾河口，DOC的主要输入来自河流和海洋，但也有大量的输入来自淡水和盐碱化的潮汐沼泽以及河口浮游植物。通过使用稳定的同位素示踪剂，我们可以跟踪这些不同来源的DOC的生产和消费情况。新出现的观点认为，陆地和海洋DOC的大背景相对较难处理，而来自藻类和沼泽的新鲜DOC在很大程度上是这些系统中细菌活动率高的原因。藻类和沼泽有时会产生大量DOC，这些DOC不会立即被细菌消耗，因此可以与潮汐一起运输。在这项提案中，研究人员将稳定同位素方法与生态系统建模相结合，以计算来自这些不同来源的DOC的生态系统水平通量，并估计每个来源的微生物消耗和溶解有机物的出口。

The cycle of dissolved organic matter in riverine saltmarsh estuaries is remarkably non-conservative. In the Parker River - Plum Island Sound estuary of northern Massachusetts there are major inputs of DOC from rivers and from the sea, but there are also large inputs from fresh and saline tidal marshes and from estuarine phytoplankton. Through the use of stable isotope tracers we can follow the production and consumption of DOC from these different sources. The emerging view is that the large background of terrestrial and oceanic DOC is relatively refractory while fresh DOC from algae and marshes is largely responsible for the high rates of bacterial activity in these systems. The algae and marshes at times produce large quantities of DOC that are not immediately consumed by bacteria and are thus available for transport with the tides. In this proposal, the investigators couple the stable isotope approach with ecosystem modeling to calculate the ecosystem level fluxes of DOC from these different sources and to estimate the microbial consumption and export of dissolved organic matter from each source.