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Biogeochemistry of organic matter and associated elements along the river-estuary-ocean continuum
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Impact of typhoon Matmo (2014) on the distribution and sources of sedimentary organic matter in the Quanzhou Bay
P-C1-05-S
Yunpeng Lin* , Laboratory for Ocean & Coast Geology, Third Institute of Oceanography, State Oceanic Administration, Xiamen
Yunhai Li, Laboratory for Ocean & Coast Geology, Third Institute of Oceanography, State Oceanic Administration, Xiamen
Presenter Email: linyunpeng@tio.org.cn |
| Estuaries and coastal areas are direct channels of material transport between land and sea, and are one of the areas with the highest primary productivity of the ocean, where large amounts of terrestrial and marine organic matter settle down. Organic matter is susceptible to a series of complex physical, chemical, and biological processes, including hydrodynamic disturbances, remineralization, decomposition and absorption by organisms during transport, deposition, and burial in these areas. These processes will change the storage and distribution state of organic matter in sediments. The typhoon process, which represents one of the most influential weather-scale atmosphere-sea interactions in marine environments, has a significant influence on the water environment and sedimentary organic matter. Therefore, it is of great significance to explore the impact of typhoon on the distribution and sources of sedimentary organic matter in estuary and coast areas.
Based on the grain-size and TOC, TN, ¦Ä13C and ¦Ä15N data of surface sediment samples collected in Quanzhou Bay under normal and post-typhoon Matmo conditions, we studied the distribution characteristics of sedimentary organic matter (SOM) in Quanzhou Bay, analyzed the sources of SOM, compared the differences between the content and distribution of SOM under both normal and post-typhoon conditions, and determined the influence mode of typhoon Matmo on the distribution and source of SOM. The results showed that the content of TOC and TN in the sediments of Quanzhou Bay decreased from the estuary to the outer bay. Combined with the value of TOC/TN and ¦Ä13C, these data indicated that sedimentary organic carbon of Quanzhou Bay had mixed sources of marine and terrestrial material, and was mainly marine sources for whole bay, while terrestrial organic matter mainly distributed in the inner bay. What¡¯s more, the outer bay has stronger microbial remineralization than inner bay. The impact of typhoon on SOM in Quanzhou Bay was mainly reflected in the increase of organic matter flux of terrestrial and sea sources, which indicated that the distribution of SOM in Quanzhou Bay was mainly controlled by the organic matter input. Furthermore, the typhoon process may inhibit the biological activities in water and sediment environments, resulting in the weakening remineralization of SOM. This study was significance to understand the source and distribution of SOM in Quanzhou Bay, and provided effective references for comprehensively exploring the impact of typhoon on estuary environment.
Keywords£ºSedimentary organic matter, Stable isotope, C/N ratio, Typhoon Matmo, Quanzhou Bay
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