Unexplained gonad alterations in whitefish (Coregonus spp.) from Lake Thun, Switzerland: levels of persistent organic pollutants in different morphs

Since 2000, a surprisingly high number of macroscopical gonad alterations has been reported in whitefish (Coregonus spp.) from Lake Thun, Switzerland. This unique phenomenon is still unexplained and has received much public attention. As one possible trigger for these effects, the presence of persistent, bioaccumulative and toxic compounds acting as endocrine disruptors in the lake has been discussed. In this study, concentrations of selected persistent organic pollutants were examined in two morphs of whitefish from Lake Thun and their link to the observed abnormalities was investigated. Analyzed compound classes included polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated naphthalenes, polybrominated diphenyl ethers and hexabromocyclododecanes. The target substances were identified in all samples and concentrations of the analyzed compounds were highly correlated among each other. These correlations show that the analyzed substances have the same distribution pattern throughout the lake and that uptake, accumulation and elimination processes are similar. Significant differences in contaminant levels within the samples existed between the two analyzed morphs of whitefish, most likely due to different age, food patterns and growth rate. No difference in contaminant levels was observed between fish with abnormal gonads and fish with normal gonads, suggesting no causal link between the investigated lipophilic organohalogen compounds present in fish and the observed gonad abnormalities in whitefish from Lake Thun. A comparison to existing data shows that concentrations in Lake Thun whitefish are at the lower bound of contaminant levels in whitefish from Swiss lakes or from European waters.     

Modellierung von Stoffausbreitungen

Die Modellierung des Ausbreitungsverhaltens von Stoffen unterschiedlicher Eigenschaften in der Umwelt stellt eine Herausforderung dar, da die zugrundeliegenden physikalischen Transport-, chemischen Reaktions- und biologischen An- oder Abreicherungsprozesse zeitlich variabel in r?umlich heterogen strukturierten Umweltsystemen wirken. Durch geschickt gew?hlte Vereinfachungen, Abgrenzungen und Mittelungen sind bemerkenswerte Erfolge bis hin zur bedingt-prognostischen Simulation ausgew?hlter Stoffe und Stoffgruppen erzielt worden. Forschungsbedarf besteht vor allem in der Modellierung der kleinr?umigen, medienübergreifenden Ausbreitung von Stoffen in komplexen ?kosystemaren Zusammenh?ngen, einschlie?lich der Austausch- und Transfervorg?nge und der chemisch-biologischen Transformationen. Bericht vom 32. Tutzing-Symposium der DECHEMA e.V., 7. bis 10. M?rz 1994     

What have we learnt from the European Union's Emissions Trading System?

The EU Emissions Trading System (ETS) demonstrated the ability to design and launch a large-scale trading system in a short period of time. The path from initial reticence about emissions trading to implementation of the world's largest program is an important history. Three issues play a large role in the evaluation of the program to date and its on-going development: allocation plans, cost uncertainty, and leakage of emissions to abroad. Decisions in Phase I and II (2005-2012) were responsive to questions of political feasibility and implementation, but some of these decisions including allocation in particular will be substantially revised in Phase III (2013-2020).     

Life stage- dependent bioconcentration of a nonylphenol isomer in Daphnia magna

Bioaccumulation is an important aspect for the fate and effects of xenobiotics in the environment. In this study we used a radiolabeled nonylphenol isomer to investigate the bioconcentration in Daphnia magna at different ages. Apart from the total radioactivity we measured the metabolism of p353-NP in D. magna, to calculate the amount of p353-NP compared to total radioactivity found within the daphnids. Bioconcentration factors, based on wet weight, calculated from the rate constants for total radioactivity in neonates and adults were 4271 kg/l and 760 kg/l respectively, leading to a 5.6 deviance in bioconcentration. This deviance was even more pronounced, nearly one order of magnitude, for the p353-NP concentration with bioconcentration factors of 302 kg/l for neonates and 31 kg/l for adults. We were able to describe the bioconcentration for all daphnids by a weight-dependent one- compartment model. These results pointed out that it is not possible to compare bioconcentration experiments conducted with different substances and different sized daphnids. Additionally it was shown that it is not possible to describe the bioconcentration by measuring the total radioactivity. Metabolism of nonylphenol occurs at a very fast rate and bioconcentration is not triggered by the partition between two phases, but by metabolism. Discrimination between the two mechanisms was achieved using radiolabeled substances and a pseudo two-compartment model to describe metabolism and elimination by two rate constants which afterwards can be compared between different substances.     

Recent European initiatives in marine protection policy: towards lasting protection for Europe's seas?

The seas and oceans are increasingly a focus of policy interest in Europe. This is mirrored in wide-ranging activities to manage and protect the marine environment, which raises the question of whether such activities go towards developing sustainable management of the seas. Sustainable management calls for an integrated and cross-sectoral approach in order to protect highly valuable marine biodiversity from sea- and land-based activities of all kinds. While some recent developments are fairly promising, there are still no moves on the policy agenda towards uniting all relevant European policy sectors – and particularly the Common Agricultural Policy and the Common Fisheries Policy – under the shared objective of sustainable management and protection of the marine environment and its resources.     

Aphanizomenon gracile (Nostocales), a cylindrospermopsin-producing cyanobacterium in Polish lakes

The cyanobacterial cytotoxin cylindrospermopsin (CYN) has become increasingly common in fresh waters worldwide. It was originally isolated from Cylindrospermopsis raciborskii in Australia; however, in European waters, its occurrence is associated with other cyanobacterial species belonging to the genera Aphanizomenon and Anabaena. Moreover, cylindrospermopsin-producing strains of widely distributed C. raciborskii have not yet been observed in European waters. The aims of this work were to assess the occurrence of CYN in lakes of western Poland and to identify the CYN producers. The ELISA tests, high-performance liquid chromatography (HPLC)-DAD, and HPLC-mass spectrometry (MS)/MS were conducted to assess the occurrence of CYN in 36 lakes. The cyrJ, cyrA, and pks genes were amplified to identify toxigenic genotypes of cyanobacteria that are capable of producing CYN. The toxicity and toxigenicity of the C. raciborskii and Aphanizomenon gracile strains isolated from the studied lakes were examined. Overall, CYN was detected in 13 lakes using HPLC-MS/MS, and its concentrations varied from trace levels to 3.0 μg?L^?1. CYN was widely observed in lakes of western Poland during the whole summer under different environmental conditions. Mineral forms of nutrients and temperature were related to CYN production. The molecular studies confirmed the presence of toxigenic cyanobacterial populations in all of the samples where CYN was detected. The toxicity and toxigenicity analyses of isolated cyanobacteria strains revealed that A. gracile was the major producer of CYN.     

Reproductive Stages Limiting Productivity of the Endangered Attwater's Prairie Chicken

An important concern of conservation biologists is determining what conditions most limit the number of individuals in endangered populations. Because time is a constraint, narrowing the search for such factors is beneficial. Toward this end we used broad spatial and temporal data, to test the hypothesis that reproductive success (as measured by juvenile-to-adult ratios) of the endangered Attwater's Prairie Chicken ( Tympanuchus cupido attwateri ) was not equal to that of the nonendangered Greater Prairie Chicken ( T. c. pinnatus ). We then tested the hypotheses that mean clutch size, egg hatchability, nesting success, and number of chicks per brood prior to brood breakup for Attwater's Prairie Chicken were not equal to those of the Greater Prairie Chicken. We found that the mean ratio of juveniles to adults among Attwater's Prairie Chicken was less than that of the Greater Prairie Chicken ( p < 0.011), as would be predicted if reproductive success controls proportional changes in prairie-grouse numbers among years. Mean nesting success (32.2%) and number of chicks per brood prior to brood breakup (4.2) of Attwater's Prairie Chicken were both less than those of the Greater Prairie Chicken (49.5 %, p = 0.0425, and 6.0 p = 0.0001, respectively). We suggest that researchers focus on determining what proportion of Attwater's Prairie Chicken broods survive and why Attwater's Prairie Chicken nesting and brood-rearing success are so poor relative to those of the Greater Prairie Chicken.