The modern sedimentary process in the mud center off the Zhejiang-Fujian coast, China

1. The modern sedimentary process in the mud center off the Zhejiang-Fujian coast, China Li Yunhai Third Institute of Oceanography, SOA, Xiamen 361005, China E-mail: liyunhai1980@gmail.com 2009.03.26 In cooperation with Chen Jian & Huang Caibin Supported by the NSFC (40806024), and (TIO2008004)

2. Background Asian Continent East China Sea Shelf The Pacific Ocean 0.4～0.8x109t/yr The Sources of sediment, discharged from large rivers. Huanghe The Sink of discharged sediment. Yellow Sea Abandoned Old Huanghe ～ 0.1x109t/yr Yangtze East China Sea ～0.5x109t/yr SeaWiFS_1997_10_8

3. Background：circulation systems in the ECS Coastal currents on the western boundary 1)Lubei coastal current; 2) North Jiangsu coastal current; 3)Zhe-Min coastal current. Kuroshio Current and its shelf branches on the eastern boundary 1)Yellow Sea Warm Current; 2)Taiwan Warm Current. In winter In summer （Pan, 2005，modified)

4. Questions: • How was the mud center formed? • How much material was from the local area along the coast? Study area (Liu et al, 2006)

5. Surveys: summer survey: August,2008 Surface sediment winter survey: December,2008 Surface sediment CTD and ADCP Sediment cores

6. Question 1: How was the mud center formed?

7. Density distribution in winter Higher-density water diffuse westward into the lower and medial water layer along shelf on sections A, D1, D2 and C, but not on section B (middle section).

8. Temperature distribution in winter Warmer water intrude westward into the lower and middle layers along the shelf on sections A, D1, D2 and C, but not on the section B (middle section).

9. Salinity distribution in winter Saline water intrude westward into the lower and medial water layer along shelf on sections A, D1, D2 and C, but not on section B (middle section).

10. Turbidity distribution in winter Highly turbid water mainly distributed in the bottom water layer, and the turbidity decreased southward and eastward, and highly turbid water (>20FTU) diffuse eastward furthest on section B.

11. Jiaojiang River Jiaojiang River Jiaojiang River 5 m below surface Jiaojiang River Jiaojiang River Jiaojiang River 5 m above bottom The horizontal distribution of water temperature, salinity and turbidity in winter

12. CHINA 40 20 10 0 20 ? 20 Taiwan 40 20 10 0 Primary Answer 1: Jiaojiang River Jiaojiang River Upwelling and downwelling might play a significant role in winter Jiaojiang River (Liu et al, 2008)

13. Qustion2: How much material was from the local area along the coast?

14. Summer survey winter survey Primary Answer 2: Jiaojiang River Jiaojiang River Mean size pattern: fine grain size with some coarse patches around the coast. The distribution of mean size of surface sediment The highest water turbidity distribute around the coast. Jiaojiang River Jiaojiang River The local sediment can not be ignored. 5 m above bottom 5 m below surface The horizontal distribution of water turbidity

15. More questions: • Seasonal variations of sediment dynamics; • Contribution and identification of the local materials: river input, coastal erosion…. • Sedimentary process recorded in the sediment cores; • ……………. • More works in progress.

16. Thank you for your attention!