Effects of transport of Minjian river substances on Minjian estuary and adjacent area

1. Effects of transport of Minjian river substances on Minjian estuary and adjacent area Aiguo GAO Department of Oceanography, College of Oceanography and Environmental Science，Xiamen University, Xiamen, Fujian, 361005, China aggao@xmu.edu.cn

3. Minjian River is the largest river in Fujian Province • The drainage basin of Minjian River takes more than half of the total area of Fujian Province, rank 12th in China. • The average flux of Minjian River is 1750 M3/s , its annual average runoff is about 62.1× 109 M3, rank 7th in China, more than Yellow River, latter’s drainage basin area is 11 times of Minjian River. • Its annual average of sediment discharge is about 7.35× 106 tons • The amount inputted the river from livestock wastes and agriculture in 2005 in upstream for CODCr, TN, and TP is about 10.21×104, 6.66×104, 2.07×104 t/yr respectively;

4. Terrigenous material • Materials from the upstream of Minjian River is transmitted to the lower reaches of the river, deposited and form the fertile plain in Fuzhou, wetlands of Minjian Estuary, and huge thick sediment in the Western Taiwan basin. • It provides abundant nourishment to fisheries such as Mindong fishery, Minzhong fishery et al. • The Material is barraged by the island of Taiwan, and redistributed in Taiwan Strait under the influence of Kuroshio branch, ZheiMin coastal flow from East China Sea and South China Sea.

5. Sediment in of Taiwan western basin • Distribution of sedimentation rates show a tendency centre by Minjian river mouth as the high sedimentation rate regions (7.1mm/a) and decrease from the coast to the mid line of the strait as the low sedimentation rate regions (0.1mm/a)． • In some place of the Taiwan western basin the thickness of sedimentary as about 8000, Oil and gas prospects are very good．

6. Problems • The increase of exploitation of variety natural resources in the Minjian area result in augmenting excessive pollutant or wastewater from industrial, agriculture, and domestic； • Irrigation works or water conservancy may change the quantity and distribution of runoff, sediment discharge, nutrients and pollutants; • Global warming may accelerate weathering in the drainage basin, will led more source material input the river and transport to the sink.

7. Problem and proposal • Those will impose on water quality, water self-purification capacity, fish’s quality and population in river system; and even more to the wetland environment, as well as water quality and ecosystems in coastal fisheries. • In order to understand mechanism of substances transportation in Minjian river system and improve the water quality of the environment, maintain the normal fishery production, protect wetland resources, make friendly ecological environmental, we propose to make a S2S project in Minjian River.

8. Stratagem • “The Minjian River drainage basin-estuary (wetlands)-adjacent sea” will be consider as an integral system in our proposal. A multi-disciplinary integrate study will be carry out under the idea “from source to sink”, to exploit the basic characteristics of how the system functions as a river-sea system under different driven force. • We hope more scientists pay much attention to Minjian river system

9. Plan • According to the river system, we divided the study area as four sections: upstream, tidal river, estuary and adjacent area; • During the first stage, we will sample water, particle, sediment, underground-water and algae in the system, analyzing the content of some typical proxies, elements (nutrient, pollutant, geochemical proxies) and isotopes (Sr ,Ra), calculate the flux in different area; • Then identify the end member of the proxies in Minjian river; • Present the environment capacity and management methods, to improve the system;

11. Prospect • It is said before the early Pleistocene, the upstream of Minjian was not connected with the lower reach, but flow into the South China Sea by Hanjian, but when they connect? What drove the process? Since then what happened? et al. • Weathering intensity and atmospheric CO2 sink in the drainage basins, contribution of geochemical flux to the change of global ocean?

12. Prospect • In the future, we will pay attention on paleo-oceanography, there may be some information related with the river, decipher the evolution history of Minjian river. • We search for collaborator to carry out science research on Minjian river system, to serve Fujian province, to tie up the scientists in both side of Taiwan strait, to provide new information for Global Change research.

13. Thank you for attention