Characteristics of wet carbon deposition in a semi-arid catchment at Loess Plateau, China.

Wet carbon deposition is a critical node of the global carbon cycle, but little is known about dissolved organic and inorganic carbon (DOC and DIC) variation and flux in semi arid area of the Loess Plateau Region (LPR). In this study, concentration of DOC and DIC in rainfall was monitored in the period of July to September 2015 at Yangjuangou catchment in the LPR. Results showed that the Volume-Weighted Mean (VWM) concentration of DOC and DIC were 24.62 and 4.30 (July), 3.58 and 10.52 (August), 1.01 and 5.89 (September) mg C L^-1. VWM concentrations of DOC and DIC for the concentrated rainy season (July-September) in the studied region were 7.06 and 7.00 mg C L^-1, respectively. In addition, the monthly deposition flux of DOC and DIC were 541.64/94.60, 131.03/385.03, and 44.44/259.16 mg C m^-2 for July, August and September. The estimated annual wet carbon depositions were 1.91, 1.89 g C m^-2 yr^-1 for DOC and DIC, which were higher than those of other sites and lower than those in the tropical and sub-tropical sites. Furthermore, the loess dust deposition process provides soil parental material in soil formation process and might be another source of carbon at the LPR. Therefore, the given results reflect characteristics of wet carbon deposition process during concentrated rainfall season in a semi-arid catchment of the LPR. Our preliminary results suggest that further investigation is needed on carbon source and deposition flux from atmosphere at long term temporal and large scale for revealing the global carbon cycle. [ABSTRACT FROM AUTHOR]