黑潮与毗邻陆架海域的碳交换

作为沟通陆架边缘海与开放大洋的北太平洋西边界流,黑潮对毗邻中国陆架海域碳循环有着不可忽视的影响。分析总结了黑潮与毗邻陆架海域海水中溶解有机碳(DOC)、颗粒有机碳(POC)、溶解无机碳(DIC)和颗粒无机碳(PIC)分布与交换的现有研究成果。分析表明,黑潮通过表层水涡旋、入侵以及次表层以下水体上涌等形式携碳进入毗邻陆架海域。在黑潮与毗邻陆架海域,DOC和POC的分布受生物活动、水团混合以及沉积物—水界面相互作用的共同影响,表层与陆架水中含量较高,DIC受海水碳酸盐体系平衡影响,表层含量低于底层,在陆架海域与上升流区有高值,PIC含量较低。在台湾东北海域,DOC,POC和DIC由东海陆架海域向黑潮有净输出,输出量分别为2 431×109,1 051×109和21 733×109mol C/a,PIC通过陆架源悬浮颗粒物向黑潮主流输送,通量为1 852×109mol C/a。DOC,POC和PIC由南海经吕宋海峡向黑潮有净输出,输出量分别为2 652×109,1 009×109和230×109mol C/a,但DIC由黑潮向南海有净输出,通量为13 005×109mol C/a。台湾海峡碳循环受黑潮输运的影响,但影响机制及过程至今并不清楚。因此,黑潮与毗邻陆架海域的碳交换过程研究还有若干重大科学问题亟待解决,尚需深入系统的研究。

Carbon Distribution and Exchange of Kuroshio and Adjacent China Sea Shelf: A Review

The Kuroshio, as the western boundary current of the North Pacific Ocean, communicates waters between China marginal seas and the open ocean, thus has vital impact on the carbon budgets in adjacent East China Sea Shelf area. The distributions and exchange processes of Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), Dissolved Inorganic Carbon (DIC) and Particulate Inorganic Carbon (PIC) between Kuroshio current and adjacent China Sea Shelf were reviewed. The Kuroshio entered the East China Sea Shelf area via eddies, intrusion and upwelling. In the study area, the distributions of DOC and POC were affected by biological activity, mixing of water masses and interaction at the sea sediment interface. Both DOC and POC were higher in the coastal area than in the Kuroshio area, and had maximum values on the surface layer. DIC, controlled by the balance of carbonate system in seawater, was higher in coastal area and upwelling area, and had minimum value in the surface water. The concentration of PIC was low. In the exchange area off northeastern Taiwan, DOC, POC and DIC were exported from shelf area to the Kuroshio current. The net export values were 2 431×10⁹, 1 051×10⁹ and 21 733×10⁹ mol C/a, respectively. Offshore transportation of suspended particles from shelf area might export PIC to Kuroshio current (1 852×10⁹ mol C/a). In Luzon Strait, DOC, POC and PIC were exported to the Kuroshio waters from South China Sea shelf area. The net export fluxes were 2 652×10⁹, 1 009×10⁹ and 230×10⁹ mol C/a, respectively. DIC had a year-round net flux export from Kuroshio to South China Sea Shelf (13 005×10⁹ mol C/a). Carbon cycling in Taiwan Strait was influenced by Kuroshio waters, but the way and extent of the influence was inconclusive. Several important questions remain to be answered before more accurate conclusions are made.