Assessment of flood-induced changes of phytoplankton along a river–floodplain system using the morpho-functional approach

In this research, we aimed to find out how the differences in hydrological connectivity between the main river channel and adjacent floodplain influence the changes in phytoplankton community structure along a river–floodplain system. The research was performed in the River Danube floodplain (Croatian river section) in the period 2008–2009 characterised by different flooding pattern on an annual time scale. By utilising the morpho-functional approach and multivariate analyses, the flood-derived structural changes of phytoplankton were analysed. The lake stability during the isolation phase triggered the specific pattern of morpho-functional groups (MFG) which were characterised by cyanobacterial species achieving very high biomass. Adversely, the high water turbulence in the lake during the frequent and extreme flooding led to evident similarity between lake and river assemblages. Besides different diatom species (groups of small and large centrics and pennates), which are the most abundant representatives in the river phytoplankton, many other groups such as cryptophytes and colonial phytomonads appeared to indicate altered conditions in the floodplain driven by flooding. Having different functional properties, small centric diatom taxa sorted to only one MFG cannot clearly reflect environmental changes that are shown by the species-level pattern. Disadvantages in using the MFG approach highlight that it is still necessary to combine it with taxonomical approach in monitoring of phytoplankton in the river–floodplain ecosystems.     

Thought for Fuelling Change: A Review of Three Models for Understanding Environmentally Significant Transitions

For over a century, western economic development has depended upon the use of combustible hydrocarbons for its energy needs. The 20th century saw the prolific exploitation of fossil hydrocarbon sources (coal and oil) which are finite and exhaustible. There is a clear need for society to conserve such non-renewable resources. In addition to conservation, a wholesale switch to renewable energy sources should be seen as the first research and development priority. In the interim, moving towards a crop-based fuel economy appears to be a good alternative to provide the necessarily dramatic changes in lifestyle and mindset that would be required of consumers, for a wholesale shift away from hydrocarbon combustion. Before programs and policies designed to address the need for an interim or alternative energy and materials economy are put into place however, it is important to understand the barriers and opportunities put forth by society itself. Conventional frameworks designed to understand this type of change are of limited assistance. This paper argues that institutional thinking is a very useful tool in addressing these types of environmental problems.     

Relative Assessment of Indicators in Sustainability Enhancement (RAISE): a first approach in the manufacturing stage of products

The estimation of the sustainability performance of products requires tools to provide systematic approaches to the definition of impacts, indicators and comparative scenarios from early design stages. This paper illustrates the Relative Assessment of Indicators in Sustainability Enhancement (RAISE) methodology that is based on the measure of negative impacts generated during any product life cycle stage. This approach includes a systematic process for the definition and evaluation of indicators to compare the sustainability performance of products considering each indicator individually and using a holistic index of sustainability to entail an overall comparison between products from manufacturing scenarios. The RAISE method is developed with the aim of assessing sustainability performance of product life cycle stages and incorporating this assessment into the decision-making process when comparing different manufacturing scenarios. A guitar capo manufactured in polymeric material is used as case study to demonstrate the use of the method. In this paper, only the manufacturing stage is considered; however, the method can also be employed in other stages of the life cycle.     

Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm⁻³, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH₄ m⁻² d⁻¹, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH₄ m⁻² d⁻¹ and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material.     

Does efficient irrigation technology lead to reduced groundwater extraction? Empirical evidence

Encouraging the use of more efficient irrigation technology is often viewed as an effective, politically feasible method to reduce the consumptive use of water for agricultural production. Despite its pervasive recommendation, it is not clear that increasing irrigation efficiency will lead to water conservation in practice. In this paper, we evaluate the effect of a widespread conversion from traditional center pivot irrigation systems to higher efficiency dropped-nozzle center pivot systems that has occurred in western Kansas. State and national cost-share programs subsidized the conversion. On an average, the intended reduction in groundwater use did not occur; the shift to more efficient irrigation technology has increased groundwater extraction, in part due to shifting crop patterns.