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

河流盐沼河口溶解有机质循环具有明显的非保守性。在马萨诸塞州北部的帕克河-梅岛湾河口，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咸水潮汐沼泽以及河口浮游植物。通过使用稳定同位素示踪剂，我们可以跟踪这些不同来源的DOC的生产和消耗。新出现的观点是，大量的陆地和海洋DOC背景相对难降解，而来自藻类和沼泽的新鲜DOC是这些系统中细菌活性高的主要原因。藻类和沼泽有时会产生大量的DOC，这些DOC不会立即被细菌消耗，因此可以随着潮汐运输。在本研究中，研究人员将稳定同位素方法与生态系统建模相结合，计算了这些不同来源的DOC的生态系统水平通量，并估计了每种来源的微生物消耗和溶解有机质的输出。

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.