Spatial gradients in dissolved carbon due to tidal marsh outwelling into a Chesapeake Bay estuary
Spatial gradients in dissolved carbon due to tidal marsh outwelling into a Chesapeake Bay estuary
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DOI：
10.3354/meps09017
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发表时间：
2011-03
影响因子：
2.5
通讯作者：
M. Tzortziou;P. Neale;J. Megonigal;Crystal Lee Pow;M. Butterworth
中科院分区：
文献类型：
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作者：
M. Tzortziou;P. Neale;J. Megonigal;Crystal Lee Pow;M. Butterworth
以前已经证明，潮汐沼泽通过充当沼泽和河口之间交换的水中输送的化合物的源、汇或转换器，影响邻近河口的碳和营养物质的通量。相对于关于这些交换的数量和方向的信息，人们对沼泽中独特的溶解有机化合物的分布和去向以及这种“沼泽特征”对河口光学和生物地球化学变异性的空间影响程度知之甚少。本文研究了切萨皮克湾罗德河口-沼泽复合体中溶解有机碳(DOC)和溶解无机碳(DIC)以及其他生物地球化学组分的空间分布。高空间分辨率断面显示，沼泽是邻近河口和大气DOC、DIC和PCO2的主要来源，它们似乎捕获藻类和其他悬浮颗粒物，同时通过潮汐冲刷向河口释放高相对分子质量、富含芳香、色彩鲜艳的溶解有机物(CDOM)。这些过程导致沼泽-河口界面以外的水体特征有很强的变异性。CDOM与盐度的非保守混合可能是由于对更不稳定的沼泽输出组分的密集处理，以及与进入河口的其他陆地和湿地输入的混合。尽管邻近的潮下泥滩可能是沼泽释放出的一些物质的汇，但沼泽的特征与进入河流1公里以上的区域河口背景是可以区分的。
Tidal marshes have been previously shown to affect fluxes of carbon and nutrients in adjacent estuaries by acting as sources, sinks or transformers of compounds transported in water exchanged between the marsh and estuary. Relative to information on the amount and direction of these exchanges, much less is known about the distribution and fate of the distinctive dissolved organic compounds derived from marshes, and the spatial extent to which this 'marsh signature' affects optical and biogeochemical variability in the estuary. In the present study we address the spa- tial distribution of both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), as well as other biogeochemical components, in the Rhode River estuary-marsh complex of the Chesapeake Bay. High-spatial-resolution transects showed that the marshes are a major source of DOC, DIC and pCO2 to the adjacent estuary and atmosphere, and that they seem to trap algae and other suspended particulate matter while releasing high-molecular-weight, aromatic-rich, highly colored dissolved organic matter (CDOM) into the estuary through tidal flushing. These processes result in strong vari- ability in water characteristics considerably beyond the marsh-estuary interface. Non-conservative mixing in CDOM with salinity was probably due to both intense processing of the more labile marsh- exported components, as well as to mixing with other terrestrial and wetland inputs into the estuary. Despite the possible role of the adjacent subtidal mudflat as a sink for some of the material released from the marshes, the marsh signature was distinguishable from the regional estuarine background over a distance of more than 1 km into the river.