Factors and Mechanisms Affecting Arsenic Migration in Cultivated Soils Irrigated with Contained Arsenic Brackish Groundwater.

Contained arsenic (As) and unsafe brackish groundwater irrigation can lead to serious As pollution and increase the ecological risk in cultivated soils. However, little is known about how Fe oxides and microbes affect As migration during soil irrigation processes involving arsenic-contaminated brackish groundwater. In this study, the samples (porewater and soil) were collected through the dynamic soil column experiments to explore the As migration process and its effect factors during soil irrigation.

Carbon‑sulfur coupling in a seasonally hypoxic, high-sulfate reservoir in SW China: Evidence from stable CS isotopes and sulfate-reducing bacteria.

Anthropogenic input of sulfate (SO) in reservoirs may enhance bacterial sulfate reduction (BSR) under seasonally hypoxic conditions in the water column. However, factors that control BSR and its coupling to organic carbon (OC) mineralization in seasonally hypoxic reservoirs remain unclear. The present study elucidates the coupling processes by analyzing the concentrations and isotopic composition of dissolved inorganic carbon (DIC) and sulfur (SO, sulfide) species, and the microbial community in water of the Aha reservoir, SW China, which has high SO concentration due to the inputs from acid mine drainage about twenty years ago.

Varying water column stability controls the denitrification process in a subtropical reservoir, Southwest China.

Reservoirs are regarded as hotspots of nitrogen transformation and potential sources of nitrous oxide (NO). However, it remains unclear how the hydrological conditions due to dam construction control the processes of nitrogen transformation in reservoir waters. To address this issue, we examined the spatial-temporal characteristics of nitrate concentrations, δN-NO, δO-NO, δO-HO, relative water column stability (RWCS), and related environmental factors in a subtropical eutrophic reservoir (Hongfeng Reservoir, HFR), Southwest China.

Distribution and speciation of arsenic in seasonally stratified reservoirs: Implications for biotransformation mechanisms governing interannual variability.

HPLC-ICPMS was used to analyze the spatiotemporal variation of As species in different sections and tributaries of the Aha Reservoir over four seasons, and the migration and transformation mechanisms were clarified by combined analysis of hydrochemical parameters and microbial composition. The results showed that the internal release of As from the reservoir sediments is mainly due to the reduction of iron oxide and the release of adsorbed As(V). The average proportion of As(III) increased from 27.

Microbial controls on heavy metals and nutrients simultaneous release in a seasonally stratified reservoir.

The eutrophication of reservoirs can change the physicochemical parameters of water, thus affecting the migration and transformation of heavy metals. At present, there is insufficient research on the coupling mechanisms between nutrients and heavy metals, especially between heavy metals in suspended particles. In this paper, spatial and temporal distribution characteristics of nutrients dissolved heavy metals, and heavy metals in suspended particles were analyzed in a seasonally stratified reservoir.

Insight into the mechanisms of denitrification and sulfate reduction coexistence in cascade reservoirs of the Jialing River: Evidence from a multi-isotope approach.

The coexistence of denitrification and bacterial sulfate reduction (BSR) processes is commonly observed in natural water systems. However, its formation mechanism remains unclear at a basin scale due to the difficulty of precise identification of these processes. To address this issue, we investigated the spatial-temporal variations in water chemistry and isotopic compositions (e.

Temporal-Spatial Pattern of Carbon Stocks in Forest Ecosystems in Shaanxi, Northwest China.

The precise and accurate quantitative evaluation of the temporal and spatial pattern of carbon (C) storage in forest ecosystems is critical for understanding the role of forests in the global terrestrial C cycle and is essential for formulating forest management policies to combat climate change. In this study, we examined the C dynamics of forest ecosystems in Shaanxi, northwest China, based on four forest inventories (1989-1993, 1994-1998, 1999-2003, and 2004-2008) and field-sampling measurements (2012). The results indicate that the total C storage of forest ecosystems in Shaanxi increased by approximately 29.