What catch data can tell us about the status of global fisheries

The only available data set on the catches of global fisheries are the official landings reported annually by the Food and Agriculture Organization of the United Nations (FAO). Attempts to detect and interpret trends in these data have been criticized as being both technically and conceptually flawed. Here, we explore and refute these claims. We show explicitly that trends in catch data are not an artifact of the applied method and are consistent with trends in biomass data of fully assessed stocks. We also show that, while comprehensive stock assessments are the preferred method for evaluating single stocks, they are a biased subsample of the stocks in a given area, strongly underestimating the percentage of collapsed stocks. We concur with a recent assessment-based analysis by FAO that the increasing trends in the percentage of overexploited, depleted, and recovering stocks and the decreasing trends in underexploited and moderately exploited stocks give cause for concern. We show that these trends are much more pronounced if all available data are considered.     

The Czech Republic’s approach to the EU 2030 climate and energy framework

ABSTRACT

The East-West divide within the EU over climate policy has been frequently discussed. There is a tendency in the literature to focus on Poland and ignore the other countries in the central and eastern European region. Here it is argued that the institutionalised cooperation between the four countries in the Visegrad Group (the Czech Republic, Hungary, Poland and Slovakia) provides a crucial component for an understanding of how the participating countries approach EU climate negotiations. Here it is suggested that the group is important as a bargaining coalition but also as a reference point for the development of shared ‘Visegrad’ norms in the field. This is based on a case study of the Czech Republic’s approach to the 2014 negotiations on the 2030 climate and energy framework and the country’s cooperation with the other Visegrad countries on the issue.     

Use of sap flow measurements to validate stomatal functions for mature beech (Fagus sylvatica) in view of ozone uptake calculations

For a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. Because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. This technique was applied in three beech (Fagus sylvatica) stands in Switzerland. A canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. It represents mainly stomatal conductance as the boundary layer resistance in forests is usually small. Based on this relative conductance, stomatal functions to describe the dependence on light, temperature, vapour pressure deficit and soil moisture were derived using multivariate nonlinear regression. These functions were validated by comparison with conductance values directly estimated from sap flow. The results corroborate the current flux parameterization for beech used in the DO₃SE model.     

Chemische Reaktionen von chlorvinylarsinverbindungen (Lewisite)

2-Chlorovinylarsine dichloride (Lewisite I) and 2,2′-dichlorodivinylarsine chloride (Lewisite II) react by room temperature rapidly and quantitatively with dithiols in a substitution reaction. The derivatives were identified with mass spectrometry. They can be detected with GC/ECD. This reactions can be used for the gas chromatographic detection of Lewisites in water and soil samples.     

Determination of chemical warfare agents in soil and material samples

A gas Chromatographic method for the determination of phenylarsenic compounds (sternutators) and their metabolites in soil and material samples is described. The chemical warfare agents (CWA), but not their hydrolysis and oxidation products, can be detected with GC/ECD. After derivatization with thiols or dithiols, the sum of diphenylarsenic and phenylarsenic compounds can be determined with GC/ECD. The comparison of the analytical results with and without derivatization shows that the sternutators in the investigated samples are metabolized in part.     

Study of leachability and fractional alteration of arsenic and co-existing elements in stabilized contaminated sludge using a flow-through extraction system

This study investigates the stabilization of As in the contaminated sludge after treatment with MnO(2) or Ca(OH)(2), and the influence of the stabilizing materials on the leachability of the co-existing elements Pb and Zn. By exploiting a continuous-flow assembly facilitating a modified Wenzel's sequential extraction scheme (designed for the fractionation of arsenic), it is possible to ascertain the leachability, mobility and fractional alteration of these elements under stimulated natural (flow-through) leaching conditions. The fractionation data show that more than 80% of As, Pb and Zn in the untreated sludge are bound in the amorphous Fe oxides fraction and residual fraction. The addition of MnO(2) has only an insignificant effect on As fractional transformation, while Ca(OH)(2) caused an increase in As mobility. For Pb, the decrease in leachability was clearly visible. The extractable Pb was reduced by 18% and 40% in stabilized MnO(2) and Ca(OH)(2) sludge samples, respectively. Unlike that of Pb, the mobility of Zn was not affected by the additives used. Their fractional distribution patterns before and after the stabilization process remained the same. The ability to produce detailed leaching profiles for As and other elements (Pb, Zn, Ca, Mn and Fe) meant that elemental associations in individual fractions could be examined. From the MnO(2)-treated sludge, the coincidence of the As, Pb, Zn, Fe, and Mn peaks seems to indicate a close association of these elements in the Fe-oxides-bound fraction. Furthermore, the leaching profiles may be used as evidence of a strong affinity between these elements and added MnO(2).     

Potential Effects of Direct Transfer Payments on Farmland Habitat Diversity in a Marginal European Landscape

Farmland habitat diversity in marginal European landscapes changed significantly in the past decades. Further changes toward homogenization are expected, particularly in the course of European agricultural policy. Based on three alternative transfer payment schemes, we modeled spatially explicit potential effects on the farmland habitat diversity in a marginal European landscape. We defined (1) a scenario with direct transfer payments coupled to production, (2) a scenario with direct transfer payments decoupled from production, and (3) a scenario phasing out all direct transfer payments. We characterized habitat diversity with three indices: habitat richness, evenness, and rarity. The habitat pattern in 1995 served as reference for comparison. All scenarios predicted a general trend of homogenization of the farmland habitat pattern, yet to a differing extent. Transfer payments coupled to production (Scenario 1) favored the abandonment of agricultural production, particularly in low-productive areas and arable land use in more productive areas. Habitat richness and habitat evenness had intermediate values in this scenario. Decoupling transfer payments from production (Scenario 2) supported grassland as most profitable farming system. This led to a grassland-dominated landscape with low values of all habitat diversity indices. Phasing out transfer payments (Scenario 3) resulted in complete abandonment or afforestation of agricultural land and extremely low values in all habitat diversity indices. Scenario results indicate that transfer payments may prevent cessation of agricultural production, but may not counteract homogenization in marginal landscapes. Conserving high farmland habitat diversity in such landscapes may require support schemes, e.g., Pillar Two of EU Common Agricultural Policy.     

Berücksichtigung von Variabilit?t und Unsicherheit in quantitativen Risikoabsch?tzungen (QRA)

Anhand des Anwendungsbeispiels einer bewohnten Altlast wird eine probabilistische Expositionsabsch?tzung durchgeführt und es werden M?glichkeiten aufgezeigt, Variabilit?t und Unsicherheit in der Sch?tzung separat zu erfassen. Zur Charakterisierung der Variabilit?t personenspezifischer Variablen (z.B. K?rpergewicht) werden in das Expositionsmodell Wahrscheinlichkeitsverteilungen eingesetzt; die stoffspezifischen Expositionsparameter werden konstant gehalten. Zus?tzlich wird die Ungewi?heit einer ausgew?hlten Variablen (Bodeningestionsrate) modelliert. Der Vergleich mit denworst-case-Sch?tzungen zeigt, da? diese in den oberen Randbereichen bzw, au?erhalb der Bereiche der probabilistischen Sch?tzung liegen und somit sehr konservative, u.U. unrealistische Sch?tzungen liefern.