Future agriculture with minimized phosphorus losses to waters: Research needs and direction

The series of papers in this issue of AMBIO represent technical presentations made at the 7th International Phosphorus Workshop (IPW7), held in September, 2013 in Uppsala, Sweden. At that meeting, the 150 delegates were involved in round table discussions on major, predetermined themes facing the management of agricultural phosphorus (P) for optimum production goals with minimal water quality impairment. The six themes were (1) P management in a changing world; (2) transport pathways of P from soil to water; (3) monitoring, modeling, and communication; (4) importance of manure and agricultural production systems for P management; (5) identification of appropriate mitigation measures for reduction of P loss; and (6) implementation of mitigation strategies to reduce P loss. This paper details the major challenges and research needs that were identified for each theme and identifies a future roadmap for catchment management that cost-effectively minimizes P loss from agricultural activities.     

Phosphorus management in Europe in a changing world

Food production in Europe is dependent on imported phosphorus (P) fertilizers, but P use is inefficient and losses to the environment high. Here, we discuss possible solutions by changes in P management. We argue that not only the use of P fertilizers and P additives in feed could be reduced by fine-tuning fertilization and feeding to actual nutrient requirements, but also P from waste has to be completely recovered and recycled in order to close the P balance of Europe regionally and become less dependent on the availability of P-rock reserves. Finally, climate-smart P management measures are needed, to reduce the expected deterioration of surface water quality resulting from climate-change-induced P loss.     

Effect of culture time on the growth curve and power performance in a microbial fuel cell at a fixed amount of liquid culture

The microbial fuel cell uses the microorganism biochemistry to carry on the energy conversion. Concerning the experimental precision, the colony culture would be replaced by a fixed amount of liquid culture for Microbial fuel cell of Escherichia coli. The anode and cathode chambers whose each volume is 100 mL were utilized, the effective surface area of proton exchange membrane Nafion-117 is about 9 cm². In addition, the electrode area of carbon cloth is 20 cm². Three kinds of Escherichia coli, named as BCRC No. 10322, 10675 and 51534, respectively, would be selected. Results show that the electricity performance of Escherichia coli of BCRC No.51534 is better than the other microorganism studied because of having a larger open circuit voltage of 1.01 V and limiting current 22 mA, the maximum power density of 1342 mW/m^2, and average working power density of 295 mW/m² would be produced. These results would be useful to improve the performance of microbial fuel cell.     

Opinions and Knowledge About Climate Change Science in High School Students

This study investigates the influence of knowledge on opinions about climate change in the emerging adults’ age group (16–17 years). Furthermore, the effects of a lecture in climate change science on knowledge and opinions were assessed. A survey was conducted in Austria and Denmark on 188 students in national and international schools before and after a lecture in climate change science. The results show that knowledge about climate change science significantly affects opinions about climate change. Students with a higher number of correct answers are more likely to have the opinion that humans are causing climate change and that both individuals and governments are responsible for addressing climate change. The lecture in climate change science significantly improved knowledge development but did not affect opinions. Knowledge was improved by 11 % after the lecture. However, the percentage of correct answers was still below 60 % indicating an urgent need for improving climate change science education.     

Spatial and temporal variability of water quality in the coral reefs of Tayrona National Natural Park,Colombian Caribbean

Tayrona National Natural Park (TNNP) is a hotspot of coral reef biodiversity in the Colombian Caribbean, located between the city of Santa Marta (>455,000 inhabitants) and several smaller river mouths (Rio Piedras, Mendihuaca, Guachaca). The region also experiences a strong seasonal variation in physical parameters (temperature, salinity, wind, and water currents) due to alternating dry seasons with coastal upwelling and rainy seasons. However, the spatial and temporal effects on water quality parameters relevant for coral reef functioning have not been investigated. Therefore, inorganic nutrient, chlorophyll a, and particulate organic carbon (POC) concentrations along with biological O₂ demand (BOD), pH, and water clarity directly above local coral reefs (~10 m water depth) were monitored for 25 months in four bays along a distance gradient (12–20 km) to Santa Marta in the southwest and to the first river mouth (17–27 km) in the east. This is by far the most comprehensive coral reefs water quality dataset for the region. Findings revealed that particularly during non-upwelling, chlorophyll a and POC concentrations along with BOD significantly increased with decreasing distance to the rivers in the east, suggesting that the observed spatial water quality decline was triggered by riverine runoff and not by the countercurrent-located Santa Marta. Nitrate, nitrite, and chlorophyll a concentrations significantly increased during upwelling, while pH and water clarity decreased. Generally, water quality in TNNP was close to oligotrophic conditions adequate for coral reef growth during non-upwelling, but exceeded critical threshold values during upwelling and in relation to riverine discharge.     

The Effect of Green Investments in an Agent-Based Climate-Economic Model

Climate-economic modeling often relies on macroeconomic integrated assessment models (IAMs) that in general try to capture how the combined system reacts to different policies. Irrespective of the specific modeling approach, IAMs suffer from two notable problems. First, although policies and emissions are dependent on individual or institutional behavior, the models are not able to account for the heterogeneity and adaptive behavior of relevant actors. Second, the models unanimously consider mitigation actions as costs instead of investments: an arguable definition, given that all other expenditures are classified as investments. Both are challenging if the long-term development of climate change and the economy shall be analyzed. This paper therefore proposes a dynamic agent-based model, based on the battle of perspectives approach (Janssen [1]; Janssen and de Vries [2]; Geisendorf [3, 4]) that details the consequences of various behavioral assumptions. Furthermore, expenditures for climate protection, e.g., the transition of the energy system to renewables, are regarded as investments in future technologies with promising growth rates and the potential to incite further growth in adjoining sectors (Jaeger et al. [5]). The paper analyzes how a different understanding of climate protection expenditures changes the system’s dynamic and, thus, the basis for climate policy decisions. The paper also demonstrates how erroneous perceptions impact on economic and climate development, underlining the importance to acknowledge heterogeneous beliefs and behavior for the success of climate policy.     

Spatial and temporal trends in water quality in a Mediterranean temporary river impacted by sewage effluents

This paper analyzes how changes in hydrological conditions can affect the water quality of a temporary river that receives direct inputs of sewage effluents. Data from 12 spatial surveys of the Vène river were examined. Physico-chemical parameters, major ion, and nutrient concentrations were measured. Analyses of variance (ANOVA) and multivariate analyses were performed. ANOVA revealed significant spatial differences for conductivity and major ion but no significant spatial differences for nutrient concentrations even if higher average concentrations were observed at stations located downstream from sewage effluent discharge points. Significant temporal differences were observed among all the parameters. Karstic springs had a marked dilution effect on the direct disposal of sewage effluents. During high-flow periods, nutrient concentrations were high to moderate whereas nutrient concentrations ranged from moderate to bad at stations located downstream from the direct inputs of sewage effluents during low-flow periods. Principal component analysis showed that water quality parameters that explained the water quality of the Vène river were highly dependent on hydrological conditions. Cluster analysis showed that when the karstic springs were flowing, water quality was homogeneous all along the river, whereas when karstic springs were dry, water quality at the monitoring stations was more fragmented. These results underline the importance of considering hydrological conditions when monitoring the water quality of temporary rivers. In view of the pollution observed in the Vène river, “good water chemical status” can probably only be achieved by improving the management of sewage effluents during low-flow periods.     

Microbiological risk infection assessment using QMRA in agriculture systems in Côte d’Ivoire,West Africa

Poor wastewater management that results from a lack of appropriate sanitation infrastructure contributes to increasing health risks in urban areas in Côte d’Ivoire. We assessed the health risks associated with the use of wastewater for watering salad destined for human consumption, to help local authorities in developing appropriate risk mitigation measures for Yamoussoukro, the political capital of Côte d’Ivoire. We applied a stochastic approach based on quantitative microbiological risk assessment (QMRA), focusing on wastewater for farming activities and salad consumption at the household level. Farming activities rely on a large degree on contaminated water and are conducted without any protection. The QMRA highlights that the poor quality of watering water increased the microbiological risk of the two assessed groups of urban farmers and individual households. The annual risk of infection due to watering wastewater in the city is estimated at 0.01 per person per year (pppy) for Giardia lamblia and 0.2 pppy for Escherichia coli O157:H7. The annual risk from salad consumption is 0.01 pppy for G. lamblia and 0.9 pppy for E. coli O157:H7. Both the annual risks from farming activities and salad consumption were higher than the tolerable standard of risk of 10^?4 pppy as defined by the World Health Organization. There is a need to conduct a risk analysis and a cost-effectiveness study on intervention to improve public health and the livelihoods of the producers which are women in majority in Yamoussoukro.     

Reliable test methods for the determination of a natural production of chloroform in soils

Chloroform is one of the most frequently found anthropogenic groundwater contaminants. Recent investigations, however, suggested that chloroform in groundwater may also originate from a natural production in soils. As societies response to the occurrence of chloroform in groundwater may depend upon its origin as anthropogenic or naturally produced, test methods are needed to measure the potential of natural soil chloroform production. Field measurements of ambient air and soil air, and field and laboratory incubation studies were evaluated for measurement of relative soil chloroform production at a site with four different vegetation types (spruce forest, beech forest, grassland, and grain field) on comparable geological soil. All test methods showed varying soil production of chloroform with spruce forest soil being most productive and grain field soil being least productive. Field measurements of the ratio of soil air to ambient air chloroform concentrations exhibited the smallest difference between high production and low production areas, whereas laboratory incubation studies showed the largest difference. Thus, laboratory incubation studies are suggested as most efficient for estimating relative chloroform production in soil. The study indicated that soil samples should be tested not more than 14 days after sampling. Furthermore, it was found that potentially limiting compounds, such as chloride or nitrate, are not needed to be added in spike experiments to obtain reliable production results. However, it should be recognized that the processes of soil chloroform production are not known yet in all details. Other factors than those studied here may affect the test methods for soil chloroform production too.     

Screening and prioritisation of chemical risks from metal mining operations, identifying exposure media of concern

Metals have been central to the development of human civilisation from the Bronze Age to modern times, although in the past, metal mining and smelting have been the cause of serious environmental pollution with the potential to harm human health. Despite problems from artisanal mining in some developing countries, modern mining to Western standards now uses the best available mining technology combined with environmental monitoring, mitigation and remediation measures to limit emissions to the environment. This paper develops risk screening and prioritisation methods previously used for contaminated land on military and civilian sites and engineering systems for the analysis and prioritisation of chemical risks from modern metal mining operations. It uses hierarchical holographic modelling and multi-criteria decision making to analyse and prioritise the risks from potentially hazardous inorganic chemical substances released by mining operations. A case study of an active platinum group metals mine in South Africa is used to demonstrate the potential of the method. This risk-based methodology for identifying, filtering and ranking mining-related environmental and human health risks can be used to identify exposure media of greatest concern to inform risk management. It also provides a practical decision-making tool for mine acquisition and helps to communicate risk to all members of mining operation teams.