Distributions of dissolved organic carbon and nitrogen in the western Okhotsk Sea and their effluxes to the North Pacific
Distributions of dissolved organic carbon and nitrogen in the western Okhotsk Sea and their effluxes to the North Pacific
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DOI：
10.1016/j.pocean.2014.05.014
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发表时间：
2014-08
影响因子：
4.1
通讯作者：
R. Sohrin;Kunimatsu Imanishi;Yoshimi Suzuki;K. Kuma;I. Yasuda;Koji Suzuki;T. Nakatsuka
中科院分区：
文献类型：
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作者：
R. Sohrin;Kunimatsu Imanishi;Yoshimi Suzuki;K. Kuma;I. Yasuda;Koji Suzuki;T. Nakatsuka
鄂霍次克海被认为是北太平洋中层水(NPIW)的唯一通风源区，它广泛分布在北太平洋的中低纬度地区。以前的研究已经证实NPIW中含有高水平的溶解有机碳(DOC)，但人们对推动鄂霍次克海DOC出口的数量和过程知之甚少。在这项研究中，2006年夏季在鄂霍次克海西部测量了DOC和溶解有机氮(DON)的浓度，并在2010年春末进行了额外的DOC测量。结果表明，DOC向中游水域(26.727.0σθ)的迁移经历了两个过程。第一个过程涉及从大陆架排放的水(密集陆架水)的扩散，这有助于库页岛东部海岸外鄂霍次克海模式水(OSMW)250-300米层的DOC和浊度最大值。第二个过程涉及千岛盆地和布斯索尔海峡的昼夜混合，DOC在那里被输送到800米以上的深度，OSMW中DOC/DON的比值在千岛盆地和布斯索尔海峡显著高于库页岛海岸外，这表明陆源有机质从库页岛盆地和布斯索尔海峡底部的输送发生在前面的区域。鄂霍次克海向北太平洋水(2 6.7~2 7.0σθ)中间层的DOC和DON外流分别为68~72Tg·C yyr−1和5.4Tg·N·yyr−1，其中以昼夜混合输送的DOC占37%。我们的结论是，千岛盆地和布索尔海峡地区的昼夜混合可能对北太平洋中游水域输出的DOC的质量和数量起到重要的调节作用。
The Okhotsk Sea is considered the only ventilation source area for North Pacific Intermediate Water (NPIW), which is widely distributed in the low and middle latitudes of the North Pacific. Previous studies have confirmed high levels of dissolved organic carbon (DOC) in NPIW, yet the amounts and the processes driving DOC export from the Okhotsk Sea are poorly understood. In this study, concentrations of DOC and dissolved organic nitrogen (DON) were measured in the western Okhotsk Sea during the summer of 2006, and additional DOC measurements were made during the late spring of 2010. Results indicate that DOC transport to the intermediate waters (26.7–27.0σθ) occurs through two processes. The first process involves the spread of water discharged from the continental shelf (Dense Shelf Water), which contributes to a DOC and turbidity maxima in the 250–300 m layer of Okhotsk Sea Mode Water (OSMW) located off the eastern Sakhalin coast. The second process involves diapycnal mixing in the Kuril Basin and the Bussol’ Strait, where DOC is transported to a depth greater than 800 m. The ratio of DOC:DON in OSMW was significantly higher in the Kuril Basin and Bussol’ Strait than off of the Sakhalin coast, which suggests that the transport of terrigenous organic matter from the bottom occurs in the former regions. DOC and DON efflux from the Okhotsk Sea to the intermediate layer in the North Pacific water (26.7–27.0σθ) were estimated to be 68–72 Tg C yr−1and 5.4 Tg N yr−1, respectively, for which the DOC transported by diapycnal mixing accounts for 37%. We conclude that diapycnal mixing in the Kuril Basin and Bussol’ Strait regions could play a significant role in regulating the quality and quantity of DOC exported to the intermediate water in the North Pacific.