Tracing solute sources and carbon dynamics under various hydrological conditions in a karst river in southwestern China.

Understanding the mechanisms that lead various hydrological conditions to influence solute and carbon dynamics in karst rivers is a crucial issue. In this study, high-frequency sampling and analyses of water chemistry and ẟC were conducted from October 2013 to September 2014 in a typical karst river, the Beipan River in southwestern China. The major ions (such as Ca, Mg, HCO, K, SO, Na, and Cl) in the river are mainly from the weathering of carbonates and silicates and present temporal hydrological variabilities.

Pretreatment method for the analysis of phosphate oxygen isotope (δO) of different phosphorus fractions in freshwater sediments.

Accurate measurement of the oxygen isotopic composition of dissolved phosphate (δO) of different phosphorus (P) fractions in lacustrine sediments is very difficult because of the influence of large amounts of impurities. In this study, we developed a five-step method for obtaining high purity AgPO sample for the analysis of δO of different P fractions in freshwater sediments. Sedimentary P was divided into NaHCO-P, NaOH-P and HCl-P by chemical sequential extraction.

[High-resolution Distribution Characteristics of Phosphorous, Iron and Sulfur Across the Sediment-Water Interface of Aha Reservoir].

two-dimension, high-resolution distribution of phosphorus(P), iron(Fe), sulfur(S) from the sediment-water interface was investigated in different areas of Aha Reservoir, a typical sub-deep water lake, using diffusive gradients in thin films(DGT) technique, combining with water chemistry and sedimentary phosphorus speciation analysis, aimed to discuss the distribution and control factors of P-Fe-S in sediments. DGT-P ranged from 0.00 mg·L to 0.