Microbial degradation pathways of the herbicide dichlobenil in soils with different history of dichlobenil-exposure

This is the first detailed study of metabolite production during degradation of the herbicide 2,6-dichlorobenzonitrile (dichlobenil). Degradation of dichlobenil and three potential metabolites: 2,6-dichlorobenzamide (BAM), 2,6-dichlorobenzoic acid (2,6-DCBA) and ortho-chlorobenzamide (OBAM) was studied in soils either previously exposed or not exposed to dichlobenil using a newly developed HPLC method. Dichlobenil was degraded in all four soils; BAM and 2,6-DCBA were only degraded in soils previously exposed to dichlobenil (100% within 35-56 days and 85-100% in 56 days, respectively), and OBAM in all four soils (25-33% removal in 48 days). BAM produced from dichlobenil was either hydrolyzed to 2,6-DCBA or dechlorinated to OBAM, which was further hydrolyzed to ortho-chlorobenzoic acid. BAM was rapidly mineralized in previously exposed soils only. All potential metabolites and the finding that BAM was a dead-end metabolite of dichlobenil in soils not previously exposed to dichlobenil needs to be included in risk assessments of the use of dichlobenil.     

Müllverbrennungs-Schlacke als Baumaterial

In order to determine the possible depreciation of its quality as a building material, solid waste residues from a municipal solid waste incinerator were analysed in a case study for its contents of various organic fractions with special emphasis on fractions which can be utilised by microbes as carbon sources. Furthermore, microbial concentrations in ashes, microbial fermentation and pH dependent viability of soil microbes in extracts of ashes were determined. Results demonstrate a low content of organic fractions in the solid waste, especially of those which can serve as C-sources for soil microbes. Microbial concentrations and rates of fermation in the ash are extremely low. The former is not only limited by the availability of suitable C-sources, but also by the alkaline pH of and the heavy metal concentration in the soil solution. Model calculations confirm that the maximal possible gas formation is extremely low and therefore does not diminish the quality of the incinerator ash as a potential building material.     

PROTECTING BEIJLNG'S MUNICIPAL WATER SUPPLY THROUGH WATERSHED MANAGEMEN AN ECONOMIC ASSESSMENT1

ABSTRACT: Watersheds above the Miyun reservoir, a principal source of surface water for Beijing, are designated to be managed for water production, but under the principle of multiple use. Because of the scarcity of arable land, these watersheds cannot be managed only for drinking water. Efforts are under way to reduce sediment delivery, improve the quality of water entering Miyun reservoir, and improve the welfare of watershed inhabitants. An economic appraisal of a watershed management project for the 3,298‐ha Shixia watershed above the Miyun reservoir, indicates a 24 percent economic rate of return on the investment made in the project. The net present value (NPV) of the project, calculated at a discount rate of 10 percent, is approximately US$3.49 million. Sensitivity analyses indicate that a doubling of labor costs lowers the NPV to US$2.07 million and a 10 percent decrease in benefits lowered the NPV to US$2.87. It is concluded that the implementation of conservation practices on the Shixia Demonstration Watershed represent an economically efficient use of resources.     

A note on a non-stationary point source spatial model

A point source, non-stationary covariance structure model is proposed, having only one additional parameter over a standard, stationary covariance structure, spatial model. Additionally, the proposed model is demonstrated to fit better than the three extra parameter, point source, non-stationary spatial model proposed by Ecker and De Oliveira (Commun Stat Theory Methods 37:2066–2078, 2008). The proposed model is fit from a Bayesian perspective and illustrated using a house sales dataset from Cedar Falls, Iowa.     

Social rank, fecundity and lifetime reproductive success in wild European rabbits (Oryctolagus cuniculus)

Wild European rabbits of both sexes have separate linear rank orders, which are established and maintained by intensive fights. This paper presents data from a 14-year study (1987-2000) on the population physiology and behavioural ecology of wild rabbits living in a 22,000 m² enclosure and focuses on the relationship between social rank and reproduction in females. Group composition, social ranks, fecundity and reproductive success were known for all females (n=197) from the outset of their first reproductive season at an age of about 300 days until their death. The annual reproductive success of females was influenced to a large extent by their social rank. This depended on two effects of about equal strength: a higher fecundity of high-ranking females and a lower mortality of their offspring between birth and adulthood. The lifetime reproductive success of the females varied greatly. Only about 50% of all females had any reproductive success (range: on to nine adult offspring). The social rank achieved by the females during their first reproductive season substantially influenced their lifetime reproductive success: The mean reproductive lifespan and lifetime fitness of high-ranking females (ranks 1 and 2) was about 60% greater than that of lower-ranking females, although many of the latter also gained dominant positions in subsequent years.     

Defensive secretions from the larvae ofApatania fimbriata (Pictet) (Trichoptera: Limnephilidae)

Summary When the larvae of the caddis flyApatania fimbriata (Pictet) are threatened, drops of fluid appear on their head capsules. The secretions are produced in a gland in the dorsal part of the prothorax. The neck region contains an eversible sac with numerous single setae, groups of 3 setae, or rows of setae on the surface. The secretion is released through two paris of orifices on the lateral sides of the sac. For the most part the secretion is composed of some 30 fatty acids, with the major components having 12–14 carbon atoms and up to 4 double bonds (approx. 1–2 µg secretion per specimen). Biotests with synthetic saturated acids (C₆–C₁₂) in a stream and in the laboratory demonstrated a paralysing effect on small invertebrate predators (Rhyacophila sp.,Plectrocnemia conspersa, Hydropsyche sp., larvae, all Trichoptera). In choice experiments,Rhyacophila sp. larvae preferred larvae ofAgapetus fuscipes andDrusus annulatus (Trichoptera) as food as compared withApatania fimbriata larvae. Larger predators, such asDinocras cephalotes (Insecta, Plecoptera) and the fishCottus gobio, did not discriminate betweenApatania fimbriata and other prey species. The use of fatty acids in defensive secretions is interpreted as an adaptation to the running water environment. They are effective repellents againstRhyacophila sp. larvae, the most important predator in the natural environment ofApatania larvae.     

Foraging and spatial organisation of the European badger,Meles meles L.

Behavioral Ecology and Sociobiology -