Temporal-spatial Distribution And The Flux Of Carbon In The Mainstream Of Yellow River

This paper is founded on the task of 973 "Study on carbon flux of the typical river in China ".The data is obtained from two cruises in October,2003 for the mainstream of yellow river and from April, 2004 to March, 2005 at huayuankou station. The temporal-spatial distribution of carbon is discussed, and the transportation flux of carbon and the carbon flux of at air-water interface are calculated in combination with the cogredient data of hydrography, chemistry and biology.1. pCO2 varies from 1100.0 to 1700.0uatm, the average is 1342.0uatm in the mainstream of yellow river. This is lower than other important river in the world. pCO2 is subjected to the carbonate system rather than the biological aerobic respiration. The mainstream of yellow river is estimated to release about 7.05 × 104tC to atmosphere per year. It is the source of CO2. This magnitude is the same as release of Ottawa River, but it is far lower release of Amazon River and marshy.2. DIC shows large value in the mainstream of yellow river, the average is 39.14mg/l, due to the carbonate system of yellow river, much more branches and complex water system. Levels of PIC are high, there is a positive correlation between the erosion of drainage area and levels of PIC. The average of DOC is 2.82 mg/l, this level is lower than other rivers, as the result of the climate of Loess Plateau which is cold and drought, few vegetation, the low ratio of chemical erosion and organic matter which is difficult to bio-degradability. There is a logarithm positive correlation between DOC and the degree of erosion, and it is maybe exterior source. POC may mainly origin from soil erosion.3. In the there stations of lanzhou, huayuankou and lijin, the flux of DIC DOC PIC and POC all increase in turn in October, 2003. Carbon flux in lijin is a little larger than huayuankou, and carbon flux in lanzhou is far away from the others.4. The value of pCO2 changes smoothly every month in a year, with the except of August. The levels are high in summer and winter, owing to sandy turbulence byhuman in summer and low temperature in winter. pCO2 varies with the carbonate system rather than the flow. DIC varies smoothly every month in a year. DIC shows small variations with flow, as the result of sandy turbulence by human and frost in the winter. PIC remains relatively stable with the exception of August, and PIC changes the same as flow and TSS. DOC shows large variations. There is high level in spring and winter and low level in summer and autumn. The effect factors are complex. POC shows large variations with flow in a year.5. PIC and POC is higher than other month, owing to bringing large number of fine sand from xiaobei mainstream. Large number of fine sand and sandy turbulence by human accelerate the balance of carbonate system, resulting in the highest level of PCO2; enhancing the level of DIC too. The value of DOC in August is a turning point between DOC and flow, as the result of human activity.