A long-term perspective of dissolved organic carbon transport in Sycamore Creek, Arizona, USA
A long-term perspective of dissolved organic carbon transport in Sycamore Creek, Arizona, USA
复制标题
美国亚利桑那州 Sycamore Creek 溶解有机碳迁移的长期视角
作者：
Jeremy B. Jones;S. Fisher;N. Grimm
对索诺兰沙漠小溪Sycamore Creek的溶解有机碳(DOC)动态进行了五年(1989-1993)的研究，重点考察了表层和浅层水中DOC的浓度和出口速率。在1989年和1990年，河流流量最少的年份(S−1年平均日流量分别为0.08m~3和0.04m~3)，DOC值较高，平均为7.37m~3和6.22m~3 L−_1(加权年平均)。而1991年至1993年为流量增长期(1·1、1·2和4·3m~3 S−1)，浓度显著降低(P<；0.001)，年平均浓度分别为3·54、3·49和3·39mgC·L−1。Sycamore Creek的DOC年出口量在五年期间变化了100倍，从1990年平均只有24kgc d−1到1993年2100kgc d−1。90%的DOC是通过流量大于2.8m~3的S−1输出的，50%是在流量大于27m~3 S−1的情况下输出的；2.8m~3和24m~3的S−1的流量分别只有9%和1%的情况发生。Sycamore Creek的有机物出口似乎与厄尔尼诺-南方涛动现象有关。出口最高的年份，1991-1993年，出现了厄尔尼诺现象，而1989年和1990年出现了中等程度的情况。
Dissolved organic carbon (DOC) dynamics were examined over five years (1989–1993) in Sycamore Creek, a Sonoran Desert stream, specifically focusing on DOC concentration in surface and hyporheic waters, and rates of export. In 1989 and 1990, the years of lowest stream discharge (0.08 and 0.04 m3 s−1 annual mean of daily discharge, respectively), DOC was high, averaging 7.37 and 6.22 mgC l−1 (weighted annual means). In contrast, from 1991 through 1993, a period of increased flow (1.1, 1.2 and 4.3 m3 s−1), concentration was significantly lower (P<0.001) with annual mean concentrations of 3.54, 3.49 and 3.39 mgC l−1. Concentration exhibited little spatial variation between two sampling stations located 6 km apart along the mainstem or between surface and hyporheic waters. Annual export of DOC from Sycamore Creek varied 100-fold over the five-year period from a mean rate of only 24 kgC d−1 in 1990 to 2100 kgC d−1 in 1993. Ninety percent of DOC was exported by flows greater than 2.8 m3 s−1, and 50% during flows greater than 27 m3 s−1; flows of 2.8 and 24 m3 s−1 occurred only 9 and 1% of the time. The export of organic matter in Sycamore Creek appears to be coupled to El Niño-Southern Oscillation phenomena. The years of highest export, 1991–1993, had El Niño conditions while 1989 and 1990 had medial conditions.