Floodplain Influence on Carbon Speciation and Fluxes from the Lower Pearl River, Mississippi
Floodplain Influence on Carbon Speciation and Fluxes from the Lower Pearl River, Mississippi
复制标题
DOI：
10.1016/j.gca.2016.05.007
复制
发表时间：
2016-08
影响因子：
5
通讯作者：
Yihua Cai;M. Shim;Laodong Guo;A. Shiller
中科院分区：
文献类型：
--
作者：
Yihua Cai;M. Shim;Laodong Guo;A. Shiller
为了研究洪泛区对碳形态和向墨西哥湾北方输出的影响，在2006-2008年期间每月采集珠江东部（EPR）流域两个地点的水样。此外，还在这两个地点之间的河流流域进行了四次空间调查。与上游采样点相比，在博加卢萨，MS，溶解无机碳（DIC）和颗粒有机碳（POC）的浓度分别低36%和55%，溶解有机碳（DOC）浓度高49%，在下游斯坦尼斯航天中心（SSC）的网站。此外，SSC的散装DOC池的胶体分数高于博加卢萨（75% vs. 68%）。详细的空间调查显示，上游和下游站之间的差异，导致从输入Hobolochitto河，EPR的支流，并从沼泽丰富的洪泛区的影响。Hobolochitto溪的EPR盆地的碳池的贡献最低，在高流量事件，并在旱季达到最大值。同时，在EPR流域的洪泛区作为一个重要的汇DOC，POC和颗粒氮在夏季和悬浮泥沙在高流量事件。然而，洪泛区被转换成悬浮泥沙，DOC和POC的EPR在冬季的来源，揭示了动态的性质和季节性的洪泛区的影响。与其主要的森林覆盖率，丰富的湿地沿着河流走廊，和轻微的人为干扰相一致，珠江流域以上博加卢萨一般有较高的DOC和POC产量（分别为1903和1386 kg-C km− 2 yr −1），但较低的DIC产量（2126 kg-C km− 2 yr −1）相比，其他北美河流。基于质量平衡方法的估计表明，河漫滩和主要河流干之间的相互作用，可以减少每年DIC和POC输出通量从下游的EPR分别为24%和40%，但提高了25%的河流DOC输出。类似的情况可能发生在其他湿地丰富的沿海河流，并能够显着改变目前估计的河流碳输出。
To investigate the floodplain influence on carbon speciation and export to the northern Gulf of Mexico, water samples were collected monthly from two sites in the East Pearl River (EPR) basin during 2006–2008. Additionally, four spatial surveys in the river basin between those two sites were also conducted. Compared with the upstream sampling site at Bogalusa, MS, dissolved inorganic carbon (DIC) and particulate organic carbon (POC) concentrations were 36% and 55% lower, respectively, and dissolved organic carbon (DOC) concentration was 49% higher at the downstream Stennis Space Center (SSC) site. In addition, the bulk DOC pool at SSC had a higher colloidal fraction than at Bogalusa (75% vs. 68%). Detailed spatial surveys revealed the differences between the upstream and downstream stations resulted both from input from Hobolochitto Creek, a tributary of the EPR, and from influence of the swamp-rich floodplain. The contributions from Hobolochitto Creek to the carbon pool in the EPR basin were lowest during a high flow event and reached a maximum during the dry season. Meanwhile, the floodplain in the EPR basin acted as a significant sink for DOC, POC and particulate nitrogen during summer and for suspended sediment during a high flow event. However, the floodplain was converted into a source of suspended sediment, DOC, and POC to the EPR during winter, revealing a dynamic nature and seasonality in the floodplain influence. Consistent with its dominant forest coverage, abundant wetlands along the river corridor, and mild anthropogenic disturbance, the Pearl River basin above Bogalusa generally had higher yields of DOC and POC (1903 and 1386 kg-C km−2yr−1, respectively), but a lower yield of DIC (2126 kg-C km−2yr−1) compared to other North American rivers. An estimation based on a mass balance approach suggests the interactions between floodplain and the main river stem could reduce the annual DIC and POC export fluxes from downstream of the EPR by 24% and 40%, respectively, but enhance the annual riverine DOC export by 25%. Similar scenarios likely occur in other wetland-rich coastal rivers and are capable of significantly altering the current estimation of riverine carbon export.