Distribution of terrestrially derived dissolved organic matter on the southeastern U.S. continental shelf
Distribution of terrestrially derived dissolved organic matter on the southeastern U.S. continental shelf
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DOI：
10.4319/lo.1991.36.6.1134
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发表时间：
1991-09
影响因子：
4.5
通讯作者：
M. Moran;L. Pomeroy;Edward S. Sheppard;L. Atkinson;R. Hodson
中科院分区：
文献类型：
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作者：
M. Moran;L. Pomeroy;Edward S. Sheppard;L. Atkinson;R. Hodson
溶解在海水中的木质素衍生化合物表明存在着来自维管植物的有机物质，因此来自陆地（高地和沿海沼泽）生态系统。我们使用疏水性树脂浓缩富含木质素的腐殖物质，并测定美国东南部大陆架沃茨的木质素氧化产物（香草基木质素酚）的浓度。木质素酚浓度范围为0.05至4.2 pg/L，占0.002-O。陆架沃茨溶解有机碳（DOC）库占总DOC库的13%。溶解木质素浓度一般最高的海岸附近，并在这些地区接受最大的河流和沼泽排放。浓度变化的短期（每周）和季节性的时间尺度上，但是，这表明陆地衍生的溶解有机物的C预算的货架的贡献是相当可变的。盐度（>~YcQ）显着相关（负）与木质素酚浓度在三个四个巡航，这表明在很大程度上保守的混合木质素衍生的材料在货架上。在选择的河流和盐沼贡献陆源有机质的大陆架，木质素酚C占DOC的0.14- 1.0%。一个简单的混合模型，假设没有生物或物理汇的木质素衍生的材料在运输过程中从陆地来源的货架预测，平均6-36%的近岸DOC来自陆地生态系统，这取决于陆地端员（木质素源）被假定为河流或盐沼。内陆架DOC和中、外陆架DOC分别有5-26%和3- 18%为陆源。
Dissolved lignin-derived compounds in seawater indicate the presence of organic matter originating from vascular plants and therefore from terrestrial (upland and coastal marsh) ecosystems. We used a hydrophobic resin to concentrate lignin-rich humic substances and to determine concentrations of lignin oxidation products (vanillyl lignin phenols) for waters of the continental shelf of the southeastern U.S. Lignin phenol concentrations ranged from 0.05 to 4.2 pg liter-’ and accounted for 0.002-O. 13% of the total dissolved organic carbon (DOC) pool in continental shelf waters. Dissolved lignin concentrations were generally highest near the shore and in those areas receiving greatest river and marsh discharge. Concentrations varied on both short-term (weekly) and seasonal time scales, however, indicating that the contribution of terrestrially derived dissolved organic matter to the C budget of the shelf is quite variable. Salinity (>~~YcQ) was significantly correlated (negatively) with lignin phenol concentrations during three of four cruises, suggesting largely conservative mixing of lignin-derived material on the shelf. In selected rivers and salt marshes contributing terrestrially derived organic matter to the continental shelf, lignin phenol C accounted for 0.14-l .O% of the DOC. A simple mixing model which assumes no biological or physical sinks oflignin-derived material during transport from terrestrial sources to the shelf predicts that an average of 6-36% of nearshore DOC derives from terrestrial ecosystems, depending on whether the terrestrial end-member (lignin source) is assumed to be a river or a salt marsh. while 5-26% of inner shelf DOC and 3-l 8% of mid- to outer-shelf DOC is of terrestrial origin.