Progress in spatiotemporal estimations of TOC transport in estuaries
Time：2020-01-02 17:18:00 Views：Author：hyyg
Recently, Dong LIU, a former doctoral student in our laboratory (now working at the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences), took the rivers entering the sea in mainland China as a typical research area and estimated the spatial and temporal changes in the total organic carbon transport in rivers entering the sea in China. The results were published In the internationally renowned journal Environment International (IF = 7.94). This result is the author's doctoral work, and the corresponding author is researcher Yan BAI in our laboratory.
Rivers entering the sea connect two major carbon pools, the land and the ocean, and the organic carbon they transport includes dissolved organic carbon (DOC) and particulate organic carbon (POC). Characteristics such as light absorption and scattering, oxygen consumption decomposition and heavy metal migration of DOC and POC will have an important impact on the marginal seawater environment. Compared with European and American rivers, Asian rivers under the influence of the East Asian monsoon have transport characteristics of high POC and low DOC/POC ratio. This has been widely reported in a large number of studies, but this conclusion is only based on survey data from a few large rivers entering the sea in Asia in the 1990s. Affected by human activities and global changes, the transport of organic carbon in rivers entering the sea is also constantly changing. Therefore, in order to better manage the marginal seawater environment and study the global carbon cycle, it is necessary to build models to obtain river organic carbon (DOC, POC) transport fluxes in different regions and years.
The research results show that the DOC and POC transport fluxes of rivers entering the sea in mainland China can be estimated from the population density, rainfall and hydrological station sediment data in the river basin; in 2008, the organic carbon transport flux of rivers entering the sea in mainland China was 9.63 Tg C, DOC and POC They are 4.61 Tg C and 5.02 Tg C respectively; among them, although the area of small rivers along the southeast coast of China only accounts for 6.68%, the DOC and POC transport volumes account for 14.28% and 17.49% of the total volume respectively; from 1953 to 2016, due to anthropogenic Due to the influence of activities, DOC transport in China's rivers entering the sea increases, but POC transport decreases, resulting in an increase in the DOC/POC ratio. Increased human activities and dam construction in the river basin are the main controlling factors for the increase in DOC transport and the decrease in POC transport respectively. This research is of great significance to understanding the impact of anthropogenic activities on environmental changes and carbon cycles in marginal seas.
Liu, D., Y. Bai, X. Q. He, C. T. A Chen, et al. Changes in riverine organic carbon input to the ocean from mainland China over the past 60 years. Environment International, 2020, 134:105258.
