Amphibian myiasis. Blowfly larvae (Lucilia bufonivora,Diptera: Calliphoridae) coping with the poisonous skin secretion of the common toad (Bufo bufo)

The blowfly Lucilia bufonivora shows high host specificity for toads despite the host’s toxic skin secretion, which consists mainly of bufadienolides. These toxins are effective blockers of the Na⁺, K⁺-ATPase, an enzyme that is essential for many physiological processes in animals. Whereas common toad (Bufo bufo) toxins were identified in the larvae of the fly, few toxins were found in the pupae and empty puparia as trace amounts, while adult flies were entirely free of these toxic compounds. Similar results were obtained when larvae of generalist necrophagous blowflies (L. sericata, Calliphora vicina) fed on toad carcasses. Analysis of the Na⁺, K⁺-ATPase gene revealed no amino acid substitution at positions known to mediate resistance to bufadienolides in other systems. Alternative mechanisms of resistance such as efficient excretion of the compounds may enable the flies to use this poisonous food source.     

Desert pastoralists’ negative and positive effects on rare wildlife in the Gobi

In arid regions of the developing world, pastoralists and livestock commonly inhabit protected areas, resulting in human–wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between pastoralists and native herbivores and carnivores. To elucidate relationships underpinning human–wildlife conflict, we synthesized 15 years of ecological and ethnographic data from Ikh Nart Nature Reserve in Mongolia's Gobi steppe. The density of argali (Ovis ammon), the world's largest wild sheep, at Ikh Nart was among the highest in Mongolia, yet livestock were >90% of ungulate biomass and dogs >90% of large‐carnivore biomass. For argali, pastoral activities decreased food availability, increased mortality from dog predation, and potentially increased disease risk. Isotope analyses indicated that livestock accounted for >50% of the diet of the majority of gray wolves (Canis lupus) and up to 90% of diet in 25% of sampled wolves (n = 8). Livestock composed at least 96% of ungulate prey in the single wolf pack for which we collected species‐specific prey data. Interviews with pastoralists indicated that wolves annually killed 1–4% of Ikh Nart's livestock, and pastoralists killed wolves in retribution. Pastoralists reduced wolf survival by killing them, but their livestock were an abundant food source for wolves. Consequently, wolf density appeared to be largely decoupled from argali density, and pastoralists had indirect effects on argali that could be negative if pastoralists increased wolf density (apparent competition) or positive if pastoralists decreased wolf predation (apparent facilitation). Ikh Nart's argali population was stable despite these threats, but livestock are increasingly dominant numerically and functionally relative to argali. To support both native wildlife and pastoral livelihoods, we suggest training dogs to not kill argali, community insurance against livestock losses to wolves, reintroducing key native prey species to hotspots of human–wolf conflict, and developing incentives for pastoralists to reduce livestock density.     

The distribution of octachlorostyrene (OCS) in environmental samples from Europe

Although octachlorostyrene (OCS) was never used as a commercial product, it may be produced during incineration and combustion processes involving chlorinated compounds. Its environmental spreading was evaluated through the analysis of several representative samples. OCS could not be measured in soil samples collected from urban and rural areas or sediments, but was present (up to 5.41 ng/g dry weight) in industrial soil collected near chemically polluted areas. For aquatic biota samples, the OCS concentrations in freshwater mussels ranged from <0.01 ng/g wet weight (ww) to 0.18 ng/g ww (mean 0.06 ng/g ww) and similar levels could be measured in 11 freshwater fish species from Belgium and Romania. A higher OCS contamination level was found in shrimps (mean 0.08 ng/g ww) compared to marine fish (mean 0.02 ng/g ww for bib and 0.01 ng/g ww for sole and whiting, respectively). OCS could also be measured in 19 harbour porpoise (Phocoena phocoena) liver samples with a mean value of 1.90 ng/g ww. According to these data, it could be computed that the biomagnification factor for OCS was one order of magnitude lower than that of HCB in the fish-porpoise food chain. The mean OCS concentrations in blue tits (Parus caeruleus) eggs and great tits (Parus major) adipose tissue were 1.24 ng/g ww and 3.24 ng/g ww, respectively. OCS could be measured in different tissues of hedgehog (Erinaceus europaeus), with the highest concentrations found in adipose tissue (mean 0.34 ng/g ww) and liver (mean 0.39 ng/g ww). In contrast, only low concentrations of OCS could be measured in human adipose tissue (up to 0.38 ng/g ww) and liver (up to 0.05 ng/g ww), while it could not be detected in human brain or lung. The relationship between the concentrations of OCS and HCB was also discussed for each species.     

Combined use of molecular biology taxonomy, Raman spectrometry, and ESEM imaging to study natural biofilms grown on filter materials at waterworks

DNA-based population analysis was applied in combination with Raman spectrometry and Environmental Scanning Electron Microscopy for the characterisation of natural biofilms from sand and activated carbon filters operated for a long term at a municipal waterworks. Whereas the molecular biology polymerase chain reaction combined with denaturing gradient gel electrophoresis approach provides a deeper insight into the bacterial biofilm diversities, Raman spectrometry analyses the chemical composition of the extracellular polymer substances (EPS), microorganisms embedded in EPS as well as other substances inside biofilm (inorganic compounds and humic substances). Microscopy images the spatial distribution of biofilms on the two different filter materials. In addition, bacterial bulk water populations were compared with biofilm consortia using the molecular fingerprint technique mentioned.Population analysis demonstrated the presence of more diverse bacterial species embedded in a matrix of EPS (polysaccharides, peptides, and nucleic acids) on the sand filter materials. In contrast to this, activated carbon granules were colonised by reduced numbers of bacterial species in biofilms. Besides α-, β-, and γ-Proteobacteria, a noticeable specific colonisation with Actinobacteria was found on activated carbon particles. Here, the reduced biofilm formation came along with a decreased EPS synthesis. The taxonomy profiles of the different biofilms revealed up to 60% similarity on the same filter materials and 32% similarity of different materials. Similarity of adherent communities from filter materials and bulk water populations from the filter effluent varied between 36% and 58% in sand filters and 6–40% in granular activated carbon filters.The biofilm investigation protocols are most crucial to subsequent acquisition of knowledge on biofilm dynamics and bacterial contributions to transformation or adsorption processes in waterworks facilities.     

Metabolites of the phenylurea herbicides chlorotoluron, diuron, isoproturon and linuron produced by the soil fungus Mortierella sp.

Phenylurea herbicides are used worldwide, and often pollute surface- and groundwater in concentrations exceeding the limit value for drinking water (0.1 μg l⁻¹). Bacteria degrade phenylurea herbicides by successive N-dealkylation to substituted aniline products. Little is known about the corresponding fungal pathways, however. We here report degradation of chlorotoluron, diuron, isoproturon and linuron by the soil fungus Mortierella sp. Gr4. Degradation was fastest with linuron and resulted in successively dealkylated metabolites and 3,4-dichloroaniline. A major new metabolite was detected that has not yet been fully identified. Thin layer chromatography and nuclear magnetic resonance spectroscopy indicate that it is a non-aromatic diol. Degradation of isoproturon, chlorotoluron and diuron involved successive N-demethylation and, in the case of isoproturon and chlorotoluron, additional hydroxylation. A new hydroxylated isoproturon metabolite was detected. The study thus shows that the fungal pathways differ from the bacterial pathways and yield new metabolites of possible environmental concern.     

Impact of Climate Change on Fish Population Dynamics in the Baltic Sea: A Dynamical Downscaling Investigation

Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated with the fish population model, and by the source of global climate data used by regional models. Knowledge of processes and biases could reduce these uncertainties.     

Chlorinated solvents in a petrochemical wastewater treatment plant: an assessment of their removal using self-organising maps

The self-organising map approach was used to assess the efficiency of chlorinated solvent removal from petrochemical wastewater in a refinery wastewater treatment plant. Chlorinated solvents and inorganic anions (11 variables) were determined in 72 wastewater samples, collected from three different purification streams. The classification of variables identified technical solvents, brine from oil desalting and runoff sulphates as pollution sources in the refinery, affecting the quality of wastewater treatment plant influent. The classification of samples revealed the formation of five clusters: the first three clusters contained samples collected from the drainage water, process water and oiled rainwater treatment streams. The fourth cluster consisted mainly of samples collected after biological treatment, and the fifth one of samples collected after an unusual event. SOM analysis showed that the biological treatment step significantly reduced concentrations of chlorinated solvents in wastewater.     

Ionic liquids as lubricants or lubrication additives: An ecotoxicity and biodegradability assessment

This paper reports on the (eco)toxicity and biodegradability of ionic liquids considered for application as lubricants or lubrication additives. Ammonium- and pyrrolidinium-based cations combined with methylsulphate, methylsulphonate and/or (CF₃SO₂)₂N⁻ anions were investigated in tests to determine their aquatic toxicity using water fleas Daphnia magna, green algae Selenastrum capricornutum and marine bacteria (Vibrio fischeri). Additional test systems with an isolated enzyme (acetylcholinesterase) and isolated leukaemia cells from rats (IPC-81) were used to assess the biological activity of the ionic liquids. These compounds generally exhibit low acute toxicity and biological activity. Their biodegradability was screened according to OECD test procedures 301 B and 301 F. For choline and methoxy-choline ionic liquids ready biodegradability was observed within 5 or 10 d, respectively. Some of the compounds selected have a considerable potential to contribute to the development of more sustainable products and processes.     

Endpoint ‘floating leaves’ of <Emphasis Type="Italic">Potamogeton natans</Emphasis>: A new method to evaluate the development of macrophytes in pond mesocosms

Goal, Scope and Background One of the advantages of long-term mesocosm experiments as compared to short-term standard toxicity tests in the laboratory is the potential for detecting secondary effects due to the interaction of species and recovery with biomass of macrophytes being an important endpoint. However, generating biomass data by harvesting is often laborious, time-consuming, costly and restricted to the end of the experiment. Moreover, valuable information may get lost, in particular in single application studies, since maximal primary effects and secondary effects or recovery occur per se at different times. Potamogeton natans was used as an example in order to test whether number and area of floating leaves can be reliably measured and be used as intermediate and final endpoints in mesocosm effect studies. Methods Digital photos, which were taken of the water surface in the course of an indoor pond mesocosm study on herbicide effects, were subjected to image analysis. The results were compared to wet weight and ash-free dry weight of Potamogeton at the end of the herbicide study. Results and Discussion Both number and area of floating leaves indicated the same herbicide effects as wet weight and ash-free dry weight of Potamogeton. Error introduced by the different work steps is small and can be further minimised by a number of method improvements. Recommendations and Perspectives In indoor mesocosm studies, errors due to the perspective adjustment may be circumvented by taking the photos perpendicular to the water surface. Correction for lens aberration, identical light conditions and the use of fluorescence images are considered promising. Field applications are proposed.     

Anaerobic inhibition and biodegradation of antibiotics in ISO test schemes

Municipal sewage is the main exposure route for antibiotics that are used in human medical care. Antibiotics that adsorb to the primary sludge and/or sur-plus activated sludge will enter the anaerobic digesters of municipal sewage treatment plants. Here anaerobic biodegradation or inhibition of anaerobic bacteria resulting in a disturbance of the process might occur. ISO standards 13641 (2003) and 11734 (1999) were used for assessing the anaerobic inhibition of 16 and the anaerobic biodegradability of 9 antibiotics respectively. Digestion sludge from a municipal sewage treatment plant (1g/l d.s.) was used as inoculum in both tests. In ISO 13641 (2003) most antibiotics showed only moderate inhibition effects after a 7 day incubation period, with EC50 values between 24 mg/l and more than 1000 mg/l (equal to mg/g d.s.). In contrast, metronidazol was decisively toxic to anaerobic bacteria with an EC50 of 0.7 mg/l. In the anaerobic degradation tests according to ISO standard 11734 (1995), only benzylpenicillin showed certain ultimate biodegradation after 60 days and most antibiotics inhibited the digesting sludge in the respective parallel tested inhibition controls. Thus the inhibition of anaerobic bacteria by antibiotics observed in the degradation tests was higher than expected from the results of the inhibition tests. The possible explanations are that distinct substrates are used (yeast extract versus sodium benzoate), that the digestion sludge loses activity during the washing steps performed for the degradation tests and that the exposure time in the degradation tests was 8 times longer than in the inhibition test.