Fuel loss and flexible fuel deposition rates in a long-distance migrant

Most migrating birds alternate flight bouts with stopovers, during which they rest and replenish the fuel used during flight (refueling). The rate of refueling (fuel deposition rate, FDR) affects stopover duration, and hence is an important determinant of the overall time required for migration. Although environmental and endogenous factors affect FDR, the urge to refuel depends on the anticipated distance to be travelled and possibly also on the amount of fuel used during the flight preceding stopover. Combining a field study with a fasting–refueling experiment on long-term captive songbirds, we tested whether the extent of fuel loss prior to refueling indeed affects FDR. In the field study, we took a comparative approach and determined FDR in two subspecies of northern wheatear (Oenanthe oenanthe) that differ greatly in the distance flown, and thus the extent of fuel used to reach our study (stopover) site. As both winter in western sub-Sahelian Africa, they face the same remaining migration distance. We found that FDR was higher in the subspecies that uses more fuel to get to our study site. Solidifying this result, in the experiment on captive northern wheatears, we found that the extent of fuel loss as a consequence of fasting explained most of the variation in subsequent FDR. The observation that experimental birds losing little fuel did not maximize their FDR suggests there are costs to rapid refueling. Our study shows that FDR is shaped not just by current environmental and endogenous conditions but also by fuel loss prior to refueling.     

Understanding the effects of rainfall on elephant-vegetation interactions around waterholes

The distribution of surface water affects herbivore-vegetation interactions in arid and semi-arid regions. Limited access to surface water typically results in the emergence of vegetation gradients around natural and artificial water sources. In particular, African elephants can create large-scale gradients of woody vegetation. Understanding the dynamics of these gradients is of particular importance for the conservation of other, less mobile herbivores that depend on woody vegetation in areas close to water. While rainfall is known to be a key determinant of herbivore-vegetation interactions in dry areas, we only have limited understanding on how it impacts woody vegetation gradients around waterholes. To address this problem, we developed a deterministic simulation model that describes the interplay of rainfall, elephants and woody vegetation in the vicinity of waterholes. The model is based on elephant telemetry data and the ecological conditions in Etosha National Park (ENP), Namibia. We found that decreasing amounts of rainfall led to an increased degradation of woody vegetation, which was particularly severe in areas close to water. Based on this result we conclude that low rainfall was an important driver of recently observed patterns of vegetation degradation in ENP. More generally, rainfall appears to be a key factor that determines elephant-vegetation interactions and thus dynamics of woody vegetation gradients around waterholes. Using long-term rainfall data from ENP, we also demonstrate that an increase in the number of water sources during periods of low rainfall can mitigate the destructive impact of elephants in areas close to water. However, more research is required to assess the sustainability and effectiveness of rainfall-adapted strategies of artificial water provisioning in more detail. In particular it is important to investigate potential effects on elephant population dynamics.     

Imprägnierte Filterpapiere für die Wasserreinigung

With special filter materials it is possible to eliminate the heavy metals lead, copper and nickel and arsenic from water by sorption resp. chemical bounding. After a reaction time of 24 hours the reduction rates were between 97% and >99,9%.     

Determination of trace perchlorate in water: a simplified method for the identification of potential interferences

Background

Perchlorate contamination of water and food poses potential health risks to humans due to the possible interference of perchlorate with the iodide uptake into the thyroid gland. Perchlorate has been found in food and drinking, surface, or swimming pool waters in many countries, including the United States, Canada, France, Germany, and Switzerland, with ion chromatography (IC) being the preferred analytical method. The standardization of a robust ion chromatographic method is therefore of the high interest for public health and safety. This article summarizes the experiments and results obtained from analyzing untreated samples, considering the sample’s electrical conductance as guidance for direct sample injection as described in EPA 314.0.

Results

The suitability of ion chromatography with suppressed conductivity detection was tested for water samples in order to check the influence of matrix effects on the perchlorate signal of untreated samples. A sample injection volume of 750 μL was applied to the selected 2 mm?IC?column. The IC?determination of perchlorate at low µg/L levels is challenged by the presence of high loads of matrix ions (e.g., chloride, nitrate, carbonate, and sulfate at 100 mg/L and above). Perchlorate recovery is impaired with the increasing matrix ion concentrations, and its chromatographic peak is asymmetric particularly at low perchlorate concentrations. The identification of the individual maximum concentration of interfering anions like chloride, nitrate, and sulfate that influence perchlorate recovery helps to reduce the number of sample preparation steps or an obligatory measurement of the electrical conductivity of the sample. Within the scope of this study, samples containing less than 125 mg/L of either anion did not need sample preparation.

Conclusion

The identification of the maximum concentration of interfering anions like chloride, nitrate, and sulfate influencing perchlorate recovery provides a simplified alternative to the EPA 314.0 method. This approach reduces unnecessary sample preparation steps while allowing a reliable prognosis of possible interferences and maintaining result quality. This study was performed to support the development of a respective international standard, which is being established by the International Organization for Standardization (ISO). The results of the study are also intended to be used as guidance for interested laboratories to optimize the analytical workflow for trace perchlorate determination.

     

Molecular biodiversity. Case study: Porifera (sponges)

Biological diversity--or biodiversity--is the term given to the variety of life on Earth and the natural patterns it forms. The biodiversity we see today is the fruit of billions of years of evolution, shaped by natural processes and, increasingly, by the influence of humans. It forms the web of life of which we are an integral part and upon which we so fully depend. The research on molecular biodiversity tries to lay the scientific foundation of a rational conservation policy that has its roots in various disciplines including systematics/taxonomy (species richness), present day ecology (diversity of ecological systems), and functional genetics (genetic diversity). The results of ongoing genome analyses (genome projects and expressed sequence tag projects) and the achievements of molecular evolution may allow us not only to quantitate the diversity of the present biota but also to extrapolate to their diversification in the future. A link between biodiversity and genomics/molecular evolution will create a platform which we hope may facilitate a sustainable management of organismic life and ensure its exploitation for human benefit. In the present review we outline possible strategies, using the Porifera (sponges) as a prominent example. On the basis of solid taxonomy and ecological data, the high value of this phylum for human application becomes obvious, especially with regard to the field of chemical ecology and the desire to find novel potential drugs for clinical use. In addition, the benefit of trying to make sense of molecular biodiversity using sponges as an example can be seen in the fact that the study of these animals, which are "living fossils", gives us a good insight into the history of our planet, especially with respect to the evolution of Metazoa.     

100 Jahre Lektinforschung — eine Bilanz

A hundred years of lectin research has led to the development of lectinology as an independent field of study. Although lectinology is in part related to immunology, fundamental differences exist. Lectins are important tools in biochemistry, histochemistry and clinical diagnosis. The essential in vivo function of lectins is to combine glycoconjugates. The function of lectins in microorganisms and in animals is partially known, whereas the function of lectins in plants is mostly unclear. Of special interest, now as before, are the toxic lectins of the ricin type consisting of an A-chain (N-glycosidase) and a B-chain (D-galactose-specific lectin).     

Environmental perspectives of pupils: the development of an attitude and behaviour scale

Summary The object of this study was to construct a measurement instrument to assess two different environmental world views of adolescents and, additionally, to address the adolescents' verbal commitment and actual behaviour. Using a multiple-choice questionnaire the instrument was designed to identify and measure the existing factors that underlie concern for ecological/environmental problems and behaviour towards environment/nature in the age group of 10 to 16 year old pupils. Within the traditional tripartite model covering cognitive, affective and behavioural components the study selected items that made up the majority of corresponding subscales from various previous studies. Using factor analysis the configuration of the scale's dimensionality was stated. Based on the responses of approximately 2000 Bavarian pupils, subscales were extracted via factor analysis and, subsequently, addressed to different segments of environmental concern ranging from attitudes to verbal commitment and actual behaviour. Correlation coefficients and the standardized Cronbach's -values were also surveyed. Additionally, a Kruskal-Wallis analysis was applied in order to locate the subscales' influences on sociodemographic variables such as gender and age and self-reported variables such as the pleasure of being a pupil and school performance. The further purpose of the present study is to provide the basis for follow-up comparisons of preferences and values in pupils within other countries.

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Résumé Le but de la présente étude est la réalisation d'un système de mesure pour l'évaluation de différents niveaux de conscience par rapport à la nature et à la protection de l'environnement, ainsi que des comportements actuels ou envisagés. Le système de mesure s'appuie sur un questionnaire à choix multiples pour évaluer les différents facteurs qui déterminent les niveaux de conscience et les comportements correspondants chez les adolescents de 10 à 16 ans. Dans le cadre du modèle à trois niveaux, qui comprend des composantes cognitives, affectives et comportementales, un grand nombre d'items, en partie issus d'études antérieures, ont été sélectionnés pour former les sous-catégories nécessaires. La configuration des catégories a été garantie par une analyse factorielle.Sur la base des réponses d'environ 2000 élèves, des sous-catégories ont été définies, qui vont depuis les positions de départ jusqu'au comportement actuel. En outre, nous avons défini les coefficients de corrélation, ainsi que les valuers Cronback-Alpha, et une analyse des régressions a été effectuée, qui prend en compte les influences, par exemple, des variables sociodémographiques comme le sexe et l'âge, des résultats scolaires ou de la manière dont l'école est perçue par chacun.La présente étude représente la base aussi bien pour des investigations comparatives entre pays, que pour l'évaluation de l'influence d'un enseignement extra-scolaire adopté.

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Dr. Franz Bogner is the senior author to whom correspondence should be addressed. Manfred Wilhelm is based at the Institut für Medizinische Statistik, Technische Universität, Ismaninger Straße 22, D-81675 München, Germany.     

Water and nitrate fluxes at a forest site in the North Tyrolean Limestone Alps

The water balance for the site Mühleggerköpfl in the North Tyrolean Limestone Alps has been established to a soil depth of 50 cm. The evaporation amounts to 42% and deep percolation is 58 % of the precipitation. The surface runoff was negligible and therefore the according nitrate fluxes as well. Soil water analysis revealed mean nitrate concentrations of 3 to 15 mg NO₃ L⁻¹, depending on soil depth. The nitrate concentrations at 50 cm soil depth and the associated percolation rates led to NO₂ ⁻N outputs of 15.9 kg NO₃ ⁻N ha⁻¹ in the year 1999 and 7.9 kg NO₃ ^∼N ha⁻¹ in the year 2000.

     

Trace elements in sediments,blue spotted tilapia Oreochromis leucostictus (Trewavas, 1933) and its parasite Contracaecum multipapillatum from Lake Naivasha,Kenya, including a comprehensive health risk analysis

This study presents the distribution of 15 major and trace elements in sediments and fish and their pericardial parasites from Lake Naivasha, Kenya. The lake is one of the few freshwater lakes in the Great Rift Valley and is under strong anthropogenic pressure mainly due to agricultural activities. Its fish provide a valuable protein source for approximately 100,000 people in the area. Fish and their parasites have been acknowledged as indicators of environmental quality due to their accumulation potential for both essential and nonessential trace elements. A total of 34 specimens of the blue spotted tilapia Oreochromis leucostictus and pooled samples of their pericardial parasite, the anisakid nematode Contracaecum multipapillatum (larvae 3), were examined. Element concentrations were determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and graphite furnace atomic absorption spectrometry (GF-AAS). The concentrations of elements in the sediments reflected the geology of the area and did not point to pollution: none of the investigated trace elements, including Pb, Cd, Cu, and Zn, showed elevated values. In contrast, concentrations in the fish muscle were elevated for Li, Sr, Cd, and Zn, with high target hazard quotients (THQ?>?0.1) indicating a potential health risk to the consumers of this fish. Fish liver showed significantly higher concentrations of the trace elements Fe, Mn, Cd, and Cu compared to the muscle and C. multipapillatum. In the parasite, Zn had the highest concentration, but the worms only minimally accumulated trace elements in relation to their fish host.