Distribution And The Flux Of Carbon In Different Periods Of Yellow River

Suzheng(2005) doing researchs in mainstream of Yellow River, the conclusion are drawn as follows: the pCO2 is higher in the water and sediment regulation than the other period , the reason of phenomenon needs more researchs. From 2002 to 2006 , there are five water and sediment regulation ,especially, the water and sediment regulation in 2005 isnot trial but a efficacious measure, so in the water and sediment regulation the are more researchs about carbon. The temporal-spatial distribution of carbon in different species, the transportation flux of carbon and the carbon flux of at air-water interface using synchronously observed data of hydrological, chemical and biological parameters are systematically studied in this dissertation. The study areas for this work are Lijin station of Yellow River during June and July, 2005 and Huayuankou station of Yellow River from November, 2005 to November, 2006. Some important researchs are drawn as follows:1. Some researchs done in Lijin station of Yellow River during June and July, 2005, the conclusion are drawn as follows: During the water and sediment regulation of Lijin, The investigation displays that there is low pCO2, high DIC and high DO during the water and sediment regulation of Lijin. In contrast, there is high pCO2, low DIC and low DO during"05.7"flood period.During the water and sediment regulation of Lijin, a good positive correlation has been found between pCO2 and DIC in the bulk water of Yellow River, suggesting that the pCO2 was controlled by the carbonate system and many sediments buffering the carbonate system led to high pCO2; During"05.7"flood period, the values of△pCO2 displays a significant relationship with AOU,the ratio of△pCO2/AOU is 0.72 which is within the range of CO2 production-to-O2 consumption ratios in biological aerobic respiration (0.62-0.90). Biological aerobic respiration plays a major role in controlling pCO2 values of bulk water during flood period, because much easily degradable terrigenous organic matters have been carried into river from land surface due to the rain washout and then biological aerobic respiration have been enhanced, consequently the values of pCO2 increase.2. During the water and sediment regulation and flood period, carbon flux from Yellow River into the sea were 10.58×104tC and 10.58×104tC, respectively, which were higher than any other period, implying that human disturbance activities—water and sediment regulation on the Yellow River estuary and flood caused by rainfall has a substantial influence on carbon flux from Yellow River into the sea.3. Some researchs done in Huayuankou station of Yellow River from November,2005 to November, 2006, the conclusion are drawn as follows: except the water and sediment regulation,DIC in huayunkou is high in spring and winter , but no fluctuation in others ;DOC is no fluctuation . Besides the water and sediment regulation , PIC is highest in summer ,then in spring , the last is in autumn and winter ;POC is higher in spring and summer than in autumn and winter .4. The values of DIC of bulk water ranged from 26.75 to 47.9 mg/L at Huayuankou station of Yellow River in a year with an average of 35.91 mg/L. The content of DIC of bulk water was weakly correlated with flow, due to the influence of more carbonate sediment caused by human activities in summer and frost caused by lower temperature in winter. With the exception of June, the PIC values of bulk water was in the range of 1.40～6.80 mg/L and the percentage of PIC in TSS occurred at 0.78%～3.21% (mean:1.53%) in a year. Weekly variation of PIC content in bulk water was well consistent with that of TSS content. The content of DOC fluctuated between 2.28 and 4.00 mg/L (average: 3.13 mg/L). In spring and autumn the content of DOC was higher, whereas lower values appeared in summer and spring. The influencing factors are complex. With the exception of June, the POC values of bulk water was in the range of 0.952～9.048 mg/L and the percentage of POC in TSS occurred at 0.151%～2.485% (mean: 0.765%) in a year. As a consequence, the content of POC were significant positively correlated with the content of TSS, indicating that POC main source is external substance transformation. From 26th November, 2005 to 7th November, 2006, annual flux of DIC, DOC, PIC and POC at Huayuankou station in Yellow River were 10.7×105 tC, 0.98×105 tC, 1.89×105 tC, 1.01×105 tC, respectively.5. The water and sediment regulation do not lead to the fluctuation of DIC and DOC , because of equality of washing out and diluting ,but a great deal of sand in the water and sediment regulation make TSS increase and farther induce that PIC(11.04mg/L) and POC(5.06mg/L) are much higher than the others .