Nitrate sink function of riparian zones induced by river stage fluctuations.

River stage fluctuation (RSF) induced by tides, dam releases, or storms may lead to enhanced nitrogen cycling (N cycling) in riparian zones (RZ). We conducted a laboratory water table manipulation experiment and applied a multiphase flow and transport model (TOUGHREACT) to investigate the role of RSF in N cycling in the RZ. Coupled nitrification and denitrification occur in the water table fluctuation zone under alternating aerobic and anaerobic conditions.

Impact of organic amendments on the bioavailability of heavy metals in mudflat soil and their uptake by maize.

Organic amendments (OAs) can be a sustainable and effective method for mudflat soil improvement. A field experiment was conducted to investigate the potential of OA application to mudflat soil improvement. We measured the pH, soil organic matter (SOM), salinity, maize growth, and heavy metal (HM) accumulation in OA-applied soils, and maize tissues after three OAs, sewage sludge (SS), Chinese medical residue (CMR), and cattle manure (CM), were applied at the application rates of 0, 30, 75, 150, and 300 t ha.

Scale-dependent biogeomorphic feedbacks control the tidal marsh evolution under Spartina alterniflora invasion.

The mechanisms of biogeomorphic feedbacks and its influencing factors have been extensively studied for pioneer species colonization in tidal environment. However, biogeomorphic impacts of alien species over the entire invasion process coupled with hydro-geomorphologic processes and ecoengineering traits still lack sufficient understanding to forecast salt marsh succession. In this study, we developed a bio-hydrogeomorphic model to account for the tidal platform evolution and vegetation distribution under Spartina alterniflora invasion in the Yellow River Delta, China.

Sustained effects of one-time sewage sludge addition on rice yield and heavy metals accumulation in salt-affected mudflat soil.

High-yielding and sustainable production of rice in salt-affected mudflat is restricted by high soil salinity. Although sewage sludge can be used for mudflat amendment especially soil salt reduction, the possibility of potential heavy metal contamination in sludge-amended mudflat especially under paddy cultivation remains unclear, which hinders the further utilization of sewage sludge. In this study, a field experiment was conducted in a newly reclaimed mudflat to assess the sustained effects of one-time sludge input with different addition rates (0, 30, 60, 120, and 180 t ha) on soil salinity, rice yield, and potential metal contamination under paddy cultivation.

Potential concerns in fullerene application to water treatment related to transformation, cellular uptake and intracellular catalysis.

Fullerene (C) exhibits versatile properties that shows great potential for improving water treatment technologies. However, the probable transformation of C during water treatment, which consequently changes the physicochemical properties and toxicity of the parent compound, may introduce doubt concerning its application. Our results demonstrated that the C aggregate (nC) was transformed to a more oxidized form under common water disinfection processes (i.

Heavy metal distribution and uptake by maize in a mudflat soil amended by vermicompost derived from sewage sludge.

Sewage sludge has been regarded as an economic and efficient soil amendment for mudflat soil amendment despite of the concern of heavy metal contamination. Converting sewage sludge into vermicompost by earthworms may be effective to minimize the risk of heavy metal contamination caused by direct application of sewage sludge in mudflat soil. The objective of this study was to assess the feasibility of vermicompost amendment (VA), and its influence on heavy metal contamination compared with sewage sludge amendment (SSA) in mudflat soil.

Water disinfection processes change the cytotoxicity of C fullerene: Reactions at the nano-bio interface.

The environmental transformation of nanoparticles results in significant changes in their structure, properties, and toxicity, which are imperative for assessing their environmental impact and health risks. Little is known about the toxicity alteration of fullerene nanoparticles (C) after water disinfection processes considering their potential application in antimicrobial control in water treatment ultimately ending in sewage treatment plants. We showed that C aggregates (nC) were converted to more oxidized forms via commonly used water disinfection processes (i.

In-situ organic phosphorus mineralization in sediments in coastal wetlands with different flooding periods in the Yellow River Delta, China.

In-situ incubation experiments were performed in typical tidal flooding wetlands and seasonal flooding wetlands in the Yellow River Delta of China to investigate sediment organic phosphorus (OP) mineralization and its influencing factors. The results showed that the sediment net P mineralization rate (R) exhibited consistent seasonal variations in both wetlands, and it was more stable in the tidal flooding wetlands than in the seasonal flooding wetlands. Sediment P mineralization was greatly influenced by plant uptake and flooding erosion, and the freshwater input by flow-sediment regulation replenished the inorganic phosphorus (IP) pool in the wetland sediments.

Sewage sludge amendment improved soil properties and sweet sorghum yield and quality in a newly reclaimed mudflat land.

Growing bioenergy crop on marginal lands has the potential to minimize land use conflicts and meet global energy demand. The newly reclaimed mudflats through sewage sludge amendment can be used as a potential marginal land for bioenergy production. This paper was one of first studies to investigate the persistent impact of sewage sludge application at the rates of 0, 25, 50, 125, and 250 t ha on selected soil physicochemical properties, yields and quality of sweet sorghum (Sorghum bicolor L.

Heavy metal leaching and plant uptake in mudflat soils amended with sewage sludge.

The leaching and uptake of Cd, Cu, Pb, and Zn by maize (Zea mays L.) in mudflat saline-alkali soils amended by sewage sludge was examined using a greenhouse leaching column experiment. Application of sewage sludge caused decreased pH, increased DOC, and increased Cd, Cu, Pb, and Zn concentrations in leachates.

A urine-fuelled soil-based bioregenerative life support system for long-term and long-distance manned space missions.

A soil-based cropping unit fuelled with human urine for long-term manned space missions was investigated with the aim to analyze whether a closed-loop nutrient cycle from human liquid wastes was achievable. Its ecohydrology and biogeochemistry were analysed in microgravity with the use of an advanced computational tool. Urine from the crew was used to supply primary (N, P, and K) and secondary (S, Ca and Mg) nutrients to wheat and soybean plants in the controlled cropping unit.

Sewage sludge as an initial fertility driver for rapid improvement of mudflat salt-soils.

Sewage sludge is by-product in the process of centralized wastewater treatment. Land application of sewage sludge is one of the important disposal alternatives. Mudflats in the interaction zone between land and sea can be important alternative sources for arable lands if amended by large amount of organic fertilizers.

The effects of household management practices on the global warming potential of urban lawns.

Nitrous oxide (N2O) emissions are an important component of the greenhouse gas (GHG) budget for urban turfgrasses. A biogeochemical model DNDC successfully captured the magnitudes and patterns of N2O emissions observed at an urban turfgrass system at the Richland Creek Watershed in Nashville, TN. The model was then used to study the long-term (i.

Effect of sewage sludge amendment on heavy metal uptake and yield of ryegrass seedling in a mudflat soil.

Mudflat soil amendment by sewage sludge is a potential way to dispose of solid wastes and increase fertility of mudflat soils for crop growth. The present study aimed to assess the impact of sewage sludge amendment (SSA) on heavy metal accumulation and growth of ryegrass ( L.) in a seedling stage.

Environmental controls on nitrogen and sulfur cycles in surficial aquatic sediments.

Enhanced anthropogenic inputs of nitrogen (N) and sulfur (S) have disturbed their biogeochemical cycling in aquatic and terrestrial ecosystems. The N and S cycles interact with one another through competition for labile forms of organic carbon between nitrate-reducing and sulfate-reducing bacteria. Furthermore, the N and S cycles could interact through nitrate [Formula: see text] reduction coupled to S oxidation, consuming [Formula: see text] and producing sulfate [Formula: see text] The research questions of this study were: (1) what are the environmental factors explaining variability in N and S biogeochemical reaction rates in a wide range of surficial aquatic sediments when [Formula: see text] and [Formula: see text] are present separately or simultaneously, (2) how the N and S cycles could interact through S oxidation coupled to [Formula: see text] reduction, and (3) what is the extent of sulfate reduction inhibition by nitrate, and vice versa.

Combined effects of short term rainfall patterns and soil texture on soil nitrogen cycling - a modeling analysis.

Precipitation variability and magnitude are expected to change in many parts of the world over the 21st century. We examined the potential effects of intra-annual rainfall patterns on soil nitrogen (N) transport and transformation in the unsaturated soil zone using a deterministic dynamic modeling approach. The model based on TOUGHREACT [corrected], which has been tested and applied in several experimental and observational systems, mechanistically accounts for microbial activity, soil moisture dynamics that respond to precipitation variability, and gaseous and aqueous tracer transport in the soil.