Phytoplankton community dynamics of two adjacent Dutch lakes in response to seasons and eutrophication control unravelled by non-supervised artificial neural networks

Long-term time-series of the eutrophic Dutch lakes Veluwemeer and Wolderwijd were subject to ordination and clustering by means of non-supervised artificial neural networks (ANN). A combination of bottom-up and top-down eutrophication control measures has been implemented in both lakes since 1979. Dividing time-series data from 1976 to 1993 into three distinctive management periods has facilitated a comparative analysis of the two lakes regarding both the seasonal and long-term dynamics in response to eutrophication control. Results of the study have demonstrated that non-supervised ANN are an alternative technique: (1) to elucidate causal relationships of complex ecological processes, and (2) to reveal long-term behaviours of ecosystems in response to different management approaches. It has been shown that external nutrient control combined with food web manipulation have turned both lakes from nitrogen to phosphorus limitation, and from blue-green algae to diatom and green algae dominance.     

Method for assessing the potential of miscanthus on marginal lands for high temperature heat demand: The case studies of France and Belgium

Energy crops on marginal lands are seen as an interesting option to increase biomass contribution to the primary energy mix. However, in the literature there is currently a lack of integrated assessments of margin land availability, energy crop production potential and supply chain optimisation. Assessing the potential and the cost of these resources in a given region is therefore a difficult task. This work also emphasises the importance on a clear definition and discussion about marginal lands and the related ethical issues embedded in the concept to ensure positive societal impacts of the results. This study proposes a methodology to estimate and analyse, in terms of economic costs, the potential of miscanthus grown on marginal lands from the production to the final point of use. Different datasets are assembled and a supply chain optimisation model is developed to minimize the total cost of the system. Miscanthus is used as a representative energy crop for the Belgian and French case studies. High temperature heat demand is considered as final use. The miscanthus can be traded by truck either in the form of chips or pellets. The results show that the miscanthus on marginal lands could supply high temperature heat up to 38 TWh in France and 1.4 TWh in Belgium with an average cost of around 50 €/t. The different sensitivity analyses showed that the yield variation has the strongest influence on the final cost, together with the distances and the cost of production of miscanthus. The main pattern observed is the local consumption of miscanthus chips and export of the surplus (if any) to the neighbouring regions. Pellets are only of marginal interest for France and are never observed for Belgium. Distances and availability of sufficient feedstocks are the two main parameters impacting the production of pellets.     

Roof runoff contamination: a review on pollutant nature,material leaching and deposition

Reviews in Environmental Science and Bio/Technology - Roof runoff is generally perceived as a relatively clean source of water and is therefore often discharged or used without any treatment....     

Flexible nest-site selection under anthropogenic habitat change in an Afrotropical understorey insectivore

Human activities impact upon natural habitats used by birds for breeding and foraging, and lead to changes in the composition and spatial distribution of predator communities, mainly through loss, fragmentation and disturbance of formerly pristine habitat. Yet possible fitness consequences of such changes through impacts on bird nest-site selection remain poorly known. Here we study nest-site selection and reproductive success of Placid Greenbuls Phyllastrephus placidus in the Taita Hills, southeast Kenya. We show that habitat features associated with nest-site selection by this insectivorous, open-cup-nesting bird species vary among forest fragments that are exposed to different levels of habitat disturbance. Such differences in sites selected for breeding result from a plastic response to fragment-specific conditions or may be driven by fragment-specific variation in the distribution and availability of certain habitat features. Given the overall high nest predation rates in our study area, we expected variation in nest-site selection to correlate with reproductive success and nestling condition, but detected no such relationship. Because predator density and nest predation rates may vary strongly in space and time, a better understanding of spatio-temporal variation in predator communities is needed to assess the possible adaptive value of nest-site selection strategies for reducing the high predation rates that are typical for this and many other open-cup-nesting tropical passerines.     

Calmodulin-stimulated cyclic nucleotide phosphodiesterase from Neurosproa crassa

Cyclic nucleotide phosphodiesterase has been partially purified by calmodulin-Sepharose affinity chromatography from a soluble extract of Neurospora crassa. The phosphodiesterase activity remained bound to the affinity column even in the presence of 6 M urea and could only be eluted by calcium chelation. The enzyme exhibits cAMP and cGMP phosphodiesterase activities. Both activities can be enhanced by calmodulin in a Ca²⁺-dependent manner. Stimulation of cyclic nucleotide phosphodiesterase by calmodulin can be inhibited by calmodulin antagonists such as pimozide, trifluoperazine and chlorpromazine.     

A multigene phylogeny demonstrates that Tuber aestivum and Tuber uncinatum are conspecific

For almost 2 centuries it has been disputed whether Tuber aestivum and Tuber uncinatum constitute two different species of truffles. Molecular markers have been applied previously to contribute to resolving this question, coming to different conclusions. In this study, we address this question by analyzing the genetic structure of truffles assigned to either of the two putative species from a geographically broad sampling across Europe. We used an approach involving multigene phylogenies and coalescent analyses of nine regions from five genes. All tests conducted supported the conspecificity of Tuber aestivum and Tuber uncinatum.     

How can we possibly resolve the planet's nitrogen dilemma?

Nitrogen is the most crucial element in the production of nutritious feeds and foods. The production of reactive nitrogen by means of fossil fuel has thus far been able to guarantee the protein supply for the world population. Yet, the production and massive use of fertilizer nitrogen constitute a major threat in terms of environmental health and sustainability. It is crucial to promote consumer acceptance and awareness towards proteins produced by highly effective microorganisms, and their potential to replace proteins obtained with poor nitrogen efficiencies from plants and animals. The fact that reactive fertilizer nitrogen, produced by the Haber Bosch process, consumes a significant amount of fossil fuel worldwide is of concern. Moreover, recently, the prices of fossil fuels have increased the cost of reactive nitrogen by a factor of 3 to 5 times, while international policies are fostering the transition towards a more sustainable agro-ecology by reducing mineral fertilizers inputs and increasing organic farming. The combination of these pressures and challenges opens opportunities to use the reactive nitrogen nutrient more carefully. Time has come to effectively recover used nitrogen from secondary resources and to upgrade it to a legal status of fertilizer. Organic nitrogen is a slow-release fertilizer, it has a factor of 2.5 or higher economic value per unit nitrogen as fertilizer and thus adequate technologies to produce it, for instance by implementing photobiological processes, are promising. Finally, it appears wise to start the integration in our overall feed and food supply chains of the exceptional potential of biological nitrogen fixation. Nitrogen produced by the nitrogenase enzyme, either in the soil or in novel biotechnology reactor systems, deserves to have a ‘renaissance’ in the context of planetary governance in general and the increasing number of people who desire to be fed in a sustainable way in particular.