Stress Resistance and Environmental Dependency of Inbreeding Depression in Drosophila melanogaster

Abstract: Both inbreeding and environmental stress can have adverse effects on fitness that affect the conservation of endangered species. Two important issues are whether stress and inbreeding effects are independent as opposed to synergistic, and whether inbreeding effects are general across stresses as opposed to stress-specific. We found that inbreeding reduced resistance to acetone and desiccation in adult Drosophila melanogaster , whereas resistance to knockdown heat stress was not affected. Inbred flies, however, experienced a greater proportional decrease in productivity than outbreds following heat stress. Correlations using line means indicated that all resistance traits were uncorrelated in the inbred as well as in the outbred flies. Recessive, deleterious alleles therefore did not appear to have any general deleterious effects on stress resistance. Inbreeding within a specific environment and selection for resistant genotypes may therefore purge a population of deleterious genes specific to only one environmental stress.     

Cross-achievements between policies for drinking water protection

Environmental dynamics have important spatial dimensions, which calls for a spatial approach in policy analyses. Further to this, assessing agri-environmental policies involves analyses of individual measures as well as their combined effects on farmer behaviour and the environment. The integration of an economic behavioural model in a spatial framework has enabled analyses of a geographically targeted subsidy scheme for drinking water protection in combination with a uniform tax on commercial nitrogen fertilizer. Results show that policy measures for reducing nitrogen use can have combined effects (cross-achievements), thereby affecting each other's cost-effectiveness. Cross-achievements between a nitrogen fertilizer tax and a subsidy scheme based on elicitation are shown not to be additive, making partial analyses of policy measures more uncertain.     

Halogenated organic contaminants in marine fish and mussels from southern Greenland--pilot study on relations to trophic levels and local sources

Mussels and marine fish (shorthorn sculpin and Greenland cod) were sampled at three locations with varying human activity. Fish livers and mussels were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and chlorinated pesticides including chlordane and toxaphene. Levels of chlorinated contaminants in shorthorn sculpins from the background location, [capital Sigma]PCB (217-224 ng g(-1) lw), [capital Sigma]DDT (180 ng g(-1) lw) and hexachlorobenzene (32-44 ng g(-1) lw), were in the same range as previously observed in eastern Greenland but exceeded the levels previously observed in southern and western Greenland. Multivariate analysis showed that pollutant concentrations were mainly explained by trophic levels of the species (cod > sculpins > mussels). A pooled sample of shorthorn sculpins from the harbour of Qaqortoq had significantly higher PCB and PBDE concentrations with a different congener pattern compared to the background site, while other contaminants were comparable. This points towards local pollution sources, possibly accumulated emissions from burning of waste.     

Nitrogen Inputs from Agriculture: Towards Better Assessments of Eutrophication Status in Marine Waters

Nutrient enrichment of coastal marine waters caused by losses of nitrate (NO₃⁻) from agriculture is an increasing global problem. In the European Union, the Nitrates Directive (ND) of 1991 was meant to be a cornerstone in reducing eutrophication effects in coastal waters downstream from intensively farmed catchments. Although reductions in losses of nitrate have been attained, very few Member States have yet been able to reduce eutrophication effects caused by inputs of NO₃⁻ from agriculture. We report trends in concentrations of NO₃⁻ and chlorophyll-a (Chl-a) in Danish coastal and open marine waters during the period from 1996 to 2011 together with an assessment of eutrophication status based on multiple indicators (e.g. nutrient concentrations, Chl-a, submerged aquatic vegetation and benthic macroinvertebrates). Despite decreasing concentrations of both NO₃⁻and Chl-a, Danish coastal waters are not yet to be classified as ‘unaffected by eutrophication’. In order to improve future pan-European evaluations of the effectiveness of the ND, we argue for the added value of including indicators and assessment principles from other European Directives, i.e. the Water Framework Directive and the Marine Strategy Framework Directive.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0514-y) contains supplementary material, which is available to authorized users.     

Long-Term Effects of Grazing and Global Warming on the Composition and Carrying Capacity of Graminoid Marshes for Moulting Geese in East Greenland

Greening of the Arctic due to climate warming may provide herbivores with richer food supplies, resulting in higher herbivore densities. In turn, this may cause changes in vegetation composition and ecosystem function. In 1982-1984, we studied the ecology of non-breeding moulting geese in Jameson Land, low Arctic East Greenland. By then, geese consumed most of the graminoid production in available moss fens, and it appeared that the geese had filled up the available habitat. In 2008, we revisited the area and found that the number of moulting geese and the temperature sum for June-July had tripled, while the above-ground biomass in a moss fen ungrazed by geese had more than doubled. In a goose-grazed fen, the overall plant composition was unchanged, but the frequency of graminoids had decreased and the area with dead vegetation and open spots had increased. We suggest that climate warming has lead to increased productivity, allowing for higher numbers of moulting geese. However, the reduction of vegetation cover by grazing may have longer term negative consequences for the number of geese the habitat can sustain.     

Photochemical transformation of the thyroid hormone levothyroxine in aqueous solution

Purpose  

The direct aqueous photolysis of the thyroid hormone levothyroxine (T₄) has been studied.     

Evaluation of the Chemcatcher and DGT passive samplers for monitoring metals with highly fluctuating water concentrations

Passive sampling devices accumulate chemicals continuously from water and can provide time weighted average (TWA) concentrations of pollutants over the exposure period. Hence, they offer a number of advantages over other conventional monitoring techniques such as spot or grab sampling. The diffusive gradient in thin film (DGT) and the Chemcatcher passive samplers can be used to provide TWA concentrations of labile metals, but the approaches to their calibration differ. DGT uses diffusion coefficients of metals in the hydrogel layer, whereas Chemcatcher uses metal specific uptake rates, with both sets of values obtained under controlled laboratory conditions with constant aqueous metal concentrations. However, little is known of how such samplers respond to fluctuating concentrations. We evaluated the responsiveness of these two passive sampling devices to rapidly changing concentrations of Cd, Cu, Ni, Pb and Zn in natural freshwater, over a relatively short deployment time. Maximum metal concentrations in water were varied between 70 and 140 microg L(-1). Experiments were carried out in a tank with a rotating carousel system and filled with Meuse river water, allowing a degree of control over experimental conditions while using natural river water. Fluctuating concentrations were obtained by stepwise addition of standard solutions of the metals. The reliability and accuracy of the TWA concentrations measured by the samplers were assessed by comparison with concentrations of the metals in spot samples of water taken regularly over the deployment period. The spot samples of water were either unfiltered (total), filtered (0.45 microm) or ultrafiltered (5 kDa). Predictive speciation modelling using the visual MINTEQ programme was also undertaken. There was reasonable agreement between the TWA concentrations of Cd and Ni obtained with Chemcatcher and DGT and the total Cd and Ni concentrations measured in repeated unfiltered spot samples. For elements (i.e. Cu, Pb, Zn) that associate to a significant degree with suspended solids, colloids or dissolved organic carbon, or form complexes with large organic ligands, optimum agreement was with the filtered or ultrafiltered fractions and with the predicted inorganic and inorganic-fulvic acid associated fractions. While Chemcatcher-based TWA concentration ranges for Cu and Zn were in best agreement with the total filtered fraction, there was lack of agreement for Pb. The combined use of DGT devices with open pore (OP) and restricted pore (RP) gels allowed the labile fraction of metal associated with large organic ligands or DOC to be differentiated and quantified, since this is available to DGT OP but unable to diffuse into the DGT RP. This evaluation of the two sampling devices clearly demonstrated their ability to react reliably to transient peaks in concentration of metal pollutants in water and indicated where future efforts are needed to improve calibration data. Such samplers may prove valuable in responding to the monitoring requirements of the European Union's Water Framework Directive.     

Trade in fisheries services under the WTO and GATS framework

This paper studies how fisheries services are classified in the World Trade Organization (WTO) framework for trade in services and discusses the potential impact of unclear classifications. The WTO plays a key role in regulation and assessment in the area of trade in services, mainly due to the General Agreement on Trade in Services (GATS), which contains the only set of multilateral rules managing such trade internationally. The purpose of GATS is to create a credible and reliable system of international trade rules that ensures fair treatment of all participants. Through negotiations, individual countries establish commitments to provide market access and limiting national treatment in various service sectors. During such negotiations, the classification of services is a prerequisite to ensure unambiguous and comparable commitments. However, the classification list used by the WTO, namely the W/120, is based on, and corresponds to, old versions of other classification lists, leading to unclear classifications. This lack of clarity in sectoral classifications makes policy analysis unnecessarily difficult and creates a risk that trade agreements may be interpreted differently by different parties.