Study Of The Carbon Content And Transportation Character Of The Yellow River In Autumn

Based on sedimentation classification, the carbon content and transportation character of The Yellow River in autumn was studied by multiple linear regression in November 2006. Meanwhile the distribution and dynamics of pCO2 was revealed in combination with the related parameters. The results indicate that:1 .The total suspended solids (TSS)is the main source of the particulate inorganic carbon(PIC). The PIC(%) is different in the same size-fractioned TSS between characteristic sample stations , though the proportion of PIC in size-fractioned TSS is always consistent , which means the transportation of PIC is consistent: the main control of transportation of PIC is attributed to the grain size of TSS; the PIC% is decreased remarkably with the increasing of the grain size of TSS, and more than 75% of PIC is concentrated in the particles (﹤32μm) . DIC is higher than the other rivers in the world due to the strong mechanical erosion and chemical weathering in the Yellow River. log(DIC/PIC) has a negative relationships with logTSS. So the main control of DIC/PIC is attributed to the total suspended solids .2.The total suspended solids (TSS)is the main source of the particulate organic carbon(POC). The POC% is different in the same size-fractioned TSS between characteristic sample stations , though the proportion of POC in size-fractioned TSS is always consistent , which means the transportation of POC is consistent: the main control of transportation of POC is attributed to the grain size of TSS; the POC% is decreased remarkably with the increasing of the grain size of TSS, and more than 80% of POC is concentrated in the fine particles (﹤16μm) while over 95% of POC is concentrated in particles of size﹤32μm. Photosynthesis has a slight contribution to POC. The POC is an important source of DOC. POC and DOC is difficult to degrade. log(DOC/POC) has a negative relationships with logTSS. So the main control of DOC/POC is attributed to the total suspended solids .3. The surface water pCO2 ranges between 788 and 1638μatm, with an average value of 1088μatm, lower than that in other important rivers in the world. Furthermore, there are significant variations in the spatial pCO2 distribution , i.e ,the pCO2 value in the middle part of the river is higher than upstream and downstream. Photosynthesis of phytoplankton has a slight effect on pCO2 . Since the organic matter level in the Yellow River water is low and hard to degrade, the biological aerobic respiration effect has little contribution to pCO2. The main controls of pCO2 is attributed to the carbonate system with high carbonate content induced by the strong mechanical erosion and chemical weathering in the Yellow River drainage area. Due to the difference in the carbon parameters , the controls of pCO2 is different between the flood and the usual.4. The flux of DIC is decuple the flux of PIC while the flux of POC is appreciably higher than the flux of DOC. The flux of inorganic carbon is notably high with OC/IC 3:25. Based on the model of Wanninkhof and the wind speed, theYellow River is estemited to release CO2 to the atmosphere about 1.15×109 molC in autumn at the rate of 0.91×mmol·m-2·s-1, which is equal to the CO2 absorption of 6.54×103km2 grass or 8.90×101km2 forest. CO2 outgassing flux of the Yellow River is near the Ottawa River and less than the Amazon River.