Preservation of black carbon in the shelf sediments of the East China Sea
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Concentrations and carbon isotopic (14C, 13C) compositions of black carbon (BC) were measured for three sediment cores collected from the Changjiang River estuary and the shelf of the East China Sea. BC concentrations ranged from 0.02 to 0.14 mg/g (dry weight), and accounted for 5% to 26% of the sedimentary total organic carbon (TOC) pool. Among the three sediment cores collected at each site, sediment from the Changjiang River estuary had relatively high BC contents compared with the sediments from the East China Sea shelf, suggesting that the Changjiang River discharge played an important role in the delivery of BC to the coastal region. Radiocarbon measurements indicate that the ages of BC are in the range of 6910 to 12250 years old B.P. (before present), that is in general, 3700 to 9000 years older than the 14C ages of TOC in the sediments. These variable radiocarbon ages suggest that the BC preserved in the sediments was derived from the products of both biomass fire and fossil fuel combustion, as well as from ancient rock weathering. Based on an isotopic mass balance model, we calculated that fossil fuel combustion contributed most (60%–80%) of the BC preserved in these sediments and varied with depth and locations. The deposition and burial of this “slow-cycling” BC in the sediments of the East China Sea shelf represent a significant pool of carbon sink and could greatly influence carbon cycling in the region.
Keywordsblack carbon marine sediment carbon cycle Changjiang River estuary East China Sea
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- 1.Goldberg E. Black Carbon in the Environment. New York: Willey, 1985Google Scholar
- 2.Penner J E, Eddleman H, Novakav T. Toward the development of a global inventory for balck carbon. Atmosph Environ, 1993, 27: 1277–1295Google Scholar
- 5.Jones T P, Chaloner W G, Kuhlbusch T A J. Proposed bio-geological and chemical based terminilogy for fire-altered plant matter. In: Clark J S, Cachier H, Goldammer J G, et al., eds. Sediment Records of Biomass Burning and Global Changes. New York: Springer, 1996. 9–22Google Scholar
- 17.Kuhlbusch T A, Crutzen P J. Black carbon, the global carbon cycle, and atmospheric carbon dioxide. In: Levine J S, ed. Biomass Burning and Global Change. Cambridge: MIT Press, 1996. 160–169Google Scholar
- 27.Guo L, Semiletov I, Gustafsson O, et al. Characterization of Siberian Arctic coastal sediments: Implications for terrestrial organic carbon export. Glob Biogeochem Cycles, 2004, 18: 1–10Google Scholar