Abstracts:Denitrification is typically the dominant process of nitrate removal in coastal wetlands, converting bioavailable N in surface waters into gases released to the atmosphere through microbial respiration. This critical function and valuable ecosystem service performed by soil microbes in coastal wetlands improves water quality and benefits the surrounding ecosystem. Five years after the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico, a layer of crude oil was found ∼5cm beneath the wetland soil surface in Bay Jimmy, LA. While previous research found potential denitrification in coastal wetland soils was significantly reduced immediately following oil exposure, this study sought to investigate the effects of the long-term presence of spilled crude oil on nitrate removal. Intact soil cores were collected from a salt marsh heavily oiled by the DWH spill, and a nearby, non-oiled site in Barataria Bay, LA. The presence of a layer of buried oil increased nitrate removal from the overlying water column, a proxy measure of denitrification, by 31.8% in intact cores compared to non-oiled cores. However, when the oil was thoroughly mixed through the surface soil intervals, there was an 18–53% decrease in the rate of denitrification. This seemingly contradictory result demonstrates that oil buried 5cm below the surface, and not in contact with the newly accreted soil, did not negatively affect areal denitrification rates. However, when oil was in direct contact and well mixed in the soil, denitrifiers in that part of the soil profile are still negatively affected.

Abstracts:Emergy theory provides a basis for assessing the added value of water resources as a function of their origin and quality. From this perspective, the sustainability of a water system and its supply to end users may be classified according to the products, services, and energy necessary for its operation, which are incorporated from the corresponding socioeconomic system and form an important aspect of its evaluation. In the present study, the development of a geoinformatics tool with an emergy accounting approach and its corresponding methodology are described, focusing on a spatial-temporal analysis of water resources and their allocation to domestic, industrial, and agricultural uses. In addition, different water provision scenarios that involve several levels of infrastructure in the basin of the Upper Course of the Lerma River (UCLR) are evaluated, and existing water deficits are considered in order to assess their economic impact and offer a perspective on regional environmental sustainability. To achieve this, the water supply processes with the greatest relevance for the UCLR basin are evaluated, which include the extraction of groundwater and the treatment of surface and wastewater for subsequent use. The evaluation of the proposed scenarios indicates that the water supply system where treated water is recycled for agricultural, industrial, and urban uses (with restrictions) has the highest value according to the environmental sustainability index. Beyond this, it is possible to establish a series of strategies to transition from the current scenario where the water supply largely comes from an overexploited aquifer, to one where wastewater treatment plants (WWTP) are capable of implementing additional units in their processes to achieve drinking water quality. Finally, the proposed methodology and the geoinformatics tool developed in this study showed their effectiveness as instruments for achieving an integrated management of water resources, which would facilitate a more objective decision making process based on current and projected scenarios.

Abstracts:Bioavailability of copper(II) to Suaeda heteroptera and Nereis succinea was analyzed in this paper by comparing the concentrations of the copper (Cu) chemical forms in sediments to the Cu concentrations in the tissues of S. heteroptera and N. succinea. The morphological distribution of heavy metals in the sediment was related to the concentration of Cu added to the sediment. In the S. heteroptera treatment groups, available Cu in sediments decreased, and N. succinea activities improved the sediment physical and chemical properties, and thus increased the bioavailable Cu for S. heteroptera uptake. The Cu contents reached 160.75mg/kg in S. heteroptera and 2801.4mg/kg in N. succinea. When S. heteroptera and N. succinea were combined, significantly more Cu was removed from the sediments than for the two working separately. Therefore, the existence of N. succinea could enhance the absorption of Cu in the coastal sediment planted with S. heteroptera and had a positive impact on environmental pollution.

Abstracts:With the development of agriculture, industry and urbanization, land-use and land-cover (LULC) change has resulted in significant deterioration of water quality and severe eutrophication in most of the lakes in China. Plateau lake ecosystem in China is very vulnerable and especially sensitive to environmental change and human disturbance, due to its strong closeness, species simplification, oligotrophy and simple food chain. This research focuses on evaluating the quantitative and spatial relationships of land use pattern and water quality of rivers inflowing to Fuxian Lake, China’s largest deep freshwater lake in plateau. To investigate the influence of spatial variation in land-use structures and topography on rivers water quality, the distributions of land-use types in the lake’s drainage basin were obtained from satellite images, and the correlations between land-use types and inflow water quality indicators were examined by applying statistical analysis and spatial analytical function of Geographic Information System. Subarea-level analysis reveals that a land-use type could exert different effects on water quality in plains and mountains, and the effects had a connection with topographic and hydrologic factors, its mixture with other land-use types, weather conditions during field measurements, as well as its scale. In addition, a comparison of correlation coefficient data for buffer regions of different scales indicated that the effect of land-use type on inflow water quality peaked in buffer regions with a radius between 100 and 200m. On the whole, the regions within 200m of river banks were the key regions that affected river water quality, and thus the construction and preservation of a riparian buffer zone in these regions can provide considerable protection from the inputs of non-point source pollutants and nutrients, and important function such as water and soil conservation. Based on these, a pollution control zoning was constructed from two key pollution control zones in the north and south, a phosphate rock pollution control zone in the northeast, a water loss and soil erosion control zone in the east, and a tourism pollution control zone in the west. This research also offers valuable insights into how to carry out subarea-level prevention and control of water pollution and regional development, according to natural environment, land use pattern and characteristics of pollution sources in different pollution control zones.

Abstracts:Stormwater runoff contains high levels of nutrients, and is regulated by the Federal National Pollution Discharge Elimination System (NPDES) to protect surface water quality. Stormwater bioretention (BR) systems are increasingly used to address these regulations. Planted BR systems remove significantly more pollutants than unplanted systems, but most studies do not attempt to verify a pollutant mass balance and seldom evaluate differences in nutrient uptake among species. This greenhouse experiment proved that an overall 98% recovery of Total Phosphorus (TP) mass over the study period was feasible for six plant species, ensuring accuracy of measurements and analyses. Additionally, it was found that Phragmites australis, Carex praegracilis, and Carex microptera uptake significantly more TP and Total Nitrogen (TN) mass into harvestable tissue than Typha latifolia, Scirpus validus, and Scirpus acutus. These results confirm that species selection can optimize nutrient retention and recovery from stormwater and decrease pollutant discharge to surface waters.

Abstracts:The purpose of this paper is to make insights into certain characteristics of nonpoint source pollution research, and consequently to show the global trends as well as assist researchers to establish future research directions. Based on the SCI-E and SSCI databases, 3246 journal articles on nonpoint source pollution were retrieved from 2001 to 2015. Nonpoint source pollution research maintained steady growth in the past 15 years. Among all countries, USA was the most active contributor with the most publications and cooperation. As for institutions, Chinese Academy of Sciences ranked first with 143 articles, and USDA-ARS in USA played a key role for intimate collaboration with other institutions. And most articles were recorded by Environmental Sciences & Ecology, Environmental Sciences and Water Resources. Further, Journal of Environmental Quality and Water Research were the most productive and influential journals, respectively. Based on keyword co-word and reference co-citation analysis by Citespace, nonpoint source pollution research includes multiple areas (control measures, modeling, pollutants, research regions and technologies). And future researches on nonpoint source pollution will likely focus on SWAT application, GIS and ecological measures.

Abstracts:Species-rich grasslands are highly threatened by land-use change, including fertilization, land-use intensification and abandonment. These changes evoke a loss of structural heterogeneity. Aside from specific management measures to increase structural heterogeneity, small-scale patches of different vegetation within grasslands are promoted naturally by soil-disturbing ecosystem engineers. The aim of this study is to analyse the importance of Lasius flavus nest mounds for increasing structural and functional diversity in vascular plant and bryophyte assemblages within Central European calcareous grasslands.

Abstracts:Biochars, the carbonaceous residue from biomass pyrolysis, have been proposed as an agriculture soil amendment to improve soil fertility and retain a broad range of environmental contaminants. The objective of this research was therefore to investigate whether the additions of cassava wastes-based biochars obtained at 750°C (noted as MS750) with the specific area of 430m²/g to an agriculture soil could effectively attenuate the transport of atrazine by using laboratory batch sorption studies and soil thin-layer chromatography. To illustrate the worst-case sorption, MS750 with different application percentages (w/w: 0%, 0.1%, 0.5%, 1%, 3%, 5%) were added into krasnozem soil only with 0.75% organic matter to determine sorption-desorption behavior and migration of atrazine. The results obtained indicated that the occurrence of cassava wastes-derived biochar significantly enhanced the sorption capacity of the soil for atrazine. The sorption affinity augmented as expected with application rates of MS750, and the distribution coefficients in biochar-added soils were greater than that in soil alone, likely due to enhancement of soil organic carbon content and favorable sorption domains for organic compounds caused by amendment of biochars. Sorption isotherms were characterized by nonlinear curves, which indicated the heterogeneous sites on MS750-soil mixture. Desorption work exhibited a remarkable impact of biochars amendment into soils on desorption of atrazine, in which an apparent hysteresis was undergone. This study clearly revealed that biochars from cassava wastes application enhanced retention of soil for atrazine to some extent, nevertheless, the magnitude of enhancement of the sorption affinity was still of dependence on the solution pH value, environmental temperature, as well as contact time between soil and biochars. The △G^o values with less than −20kJ/mol and the effect of solution pH variation on sorption capacity of 6 sorbents indicated that the equilibrium process may be involved physisorption, as well as accompanied with chemisorption. The results from thermodynamic analysis showed that sorption of atrazine in soils amended with MS750 was thermodynamically endothermic. Positive correlation between the mobility level of pesticide and the addition percentage of biochars suggested that the application of biochars derived from cassava waste was available to retain pesticides and attenuate the leach into groundwater. These observations provide important information on the application of biochars produced at 750°C as engineered sorbents for soil remediation and compounds elimination.

Abstracts:The phosphorus (P) distribution and sorption-release characteristics of the surface soil in new submerged areas from the Danjiangkou Reservoir were investigated, and assessed the potential risk of P released from the soils. The results indicated that the TP (total phosphorus) contents in the soils varied from 161.01mg/kg to 1150.94mg/kg, and the mean content value of TP was the highest in arable land (732.91mg/kg), especially distributed in arable land above 160m elevation; Calcium bound phosphorus (HCl-P) was the major fraction of TP, the proportion was ranged from 60.77% to 83.38% for different land using types; the highest proportion of OP (organic phosphorus) was 32.07% in grass land soils. For all the samples, the rank order P-fractions was HCl-P>OP>NaOH-P (Phosphorus bound to Al and Fe oxides). Besides, the contents of TP correlated significantly with the HCl-P contents, (r=0.936, P<0.01), NaOH-P contents (r=0.661, P<0.01), OP contents (r=0.762, P<0.01), and IP contents (r=0.970, P<0.01), but OP contents was no significantly correlated with HCl-P, NaOH-P contents. The sorption capacity of soil ranged from 578.79 to 1457.44mg/kg, and the amount of P released from the soils were ranged from 0.635 to 5.957mg/kg; however, due to the concentration of P in the overlying water, about 80% of the newly submerged area would act as sink of P.

Abstracts:Hydrological alteration caused by dam operation and river modification has affected the habitat of microorganisms by directly changing soil physical and chemical environment in the hillslope riparian zone. However, the changes in the hillslope riparian zone’s soil microbial biomass and qCO2 caused by a range of annual cyclic water-level fluctuations over time have received considerably less attention. Three subsites with different durations of annual cyclic drainage in riparian zone were chosen for soil microbial biomass carbon, microbial biomass nitrogen and qCO2 measurement during the drainage across a hillslope riparian elevation in Three Gorges Reservoir Area for two years from 2011 to 2012. The studied subsites included shorter drainage (SD) at 145–155m above sea level, middle drainage (MD) at 155–165m above sea level, and longer drainage (LD) at 165–175m above sea level. One adjacent upland site that was never inundation (NI) at 175–185m above sea level was used as a control. The analysis of covariance (ANCOVA) indicated that the elevation gradient and the time of sampling significantly affected soil microbial biomass carbon and soil qCO2. Soil microbial biomass carbon and microbial biomass nitrogen were lower in the riparian zone than the upland site. In the riparian zone, microbial biomass carbon was lower in SD (126.63mgkg⁻¹) than those of MD (217.33mg⁻¹) and LD (220.99mgkg⁻¹), both of which exhibited no significant difference in May 2011. However, in July 2012, the microbial biomass carbon values followed the order: MD>LD>SD. Microbial biomass nitrogen had no significant difference among three riparian zone subsites in May 2011. In July 2012, microbial biomass nitrogen was lower in SD (22.17mgkg⁻¹) than MD (29.17mgkg⁻¹) and LD (29.7mgkg⁻¹), both of which had no significant difference. Soil qCO2 was higher in SD than those of MD, LD, and NI in both May 2011 and July 2012. Microbial biomass carbon was higher in July 2012 than in May 2011, whereas soil qCO2 was lower in July 2012 than in May 2011. Overall, soil microbial biomass showed a significantly positive relationship with organic carbon and total nitrogen. Soil qCO2 showed a negative relationship with organic carbon, microbial biomass carbon, and microbial biomass nitrogen. Therefore, the results suggested that soil microbial biomass and metabolic quotient were sensitive indicators of hydrological alteration in hillslope riparian zone as a consequence of dam operation.