Physiologische anpassungen eines marinen insekts. I. Die zeitliche steuerung der entwicklung

The Baltic populations of Clunio marinus (Chironomidae, Diptera) differ from their Atlantic counterparts in three ways: they neither pupate nor hatch in synchrony with a lunar rhythm; they live in a permanently submersed habitat; the structures of their gelatinous egg-masses are different. C. marinus produces two generations each year. The spring generation, which hibernates in the 4th larval stage, hatches in May; the summer generation hatches at the end of July or beginning of August; hatching periods last only a few days. In the laboratory, a permanent short-day period (8 h light, 16 h dark; LD 8:16) induces larval quiescence (oligopause), which can be terminated by long-day conditions (ca. LD 16:8). If larval populations are exposed to continuous light (LL) for 4 days every 30 days, particularly large numbers of imagos hatch about the time of the next LL-period. Increased illumination may influence the time of hatching. Raising the temperature for a few days does not affect hatching. The roles of photoperiod, illumination and temperature are discussed with regard to the temporal programming of development and the start of mass hatching in the natural habitat.

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Herrn Professor Dr. D. Neumann danke ich für die Anregung und Betreuung dieser Arbeit, die Teil einer Dissertation ist.

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Communicated by O. Kinne, Hamburg     

Zum Patentschutz chemischer und biologischer Erfindungen

The Science of Nature -     

Verbleib von spurenschadstoffen bei der methylesterherstellung aus altspeisefett im technikumsmaßstab

Aims and Scope

In Germany, 120,000 tons per year of waste edible fats are collected from the catering and the food industry Until recently, these fats have widely been used as a nutritional additive for poultry and other animals fodder. Due to the BSE crisis and some affairs based on dioxins in feeding stuff, waste fats are now barely used as fodder. Currently, these fats substitute fresh vegetable oils in the chemical industry and are used as raw material for the production of biodiesel. Therefore, alternative fields of application are required. In this context, the Deutsche Bundesstiftung Umwelt (DBU) is sponsoring a joint research project which deals with the production and testing of cooling lubricants based on monoesters made from waste edible fats.

Methods

In a first step, characteristics and quality of wasteedible fats of different origins were chemically analysed and monitored. The investigations covered the following fat specific parameters: total contamination, sulphate ash, water content, peroxide number, iodine value, kinematical viscosity, neutralisation number (free fatty acids) and fatty acid spectra. In the next step, a process development/optimisation was carried out for the production of methylesters based on the raw material waste fat, leading to the construction of a pilot plant. To investigate the fate of trace pollutants during the production process of waste-fat methylester, samples were systematically contaminated with polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and the elements Al, Cd, Cr, Cu, Ni, P, Pb, Sn, and Zn. These contaminated fat samples were transesterified in laboratory scale. The primary and by-products were analysed subsequently.

Results

Valuable hints on the design of the technical process of fatty adid methylester production based on waste edible fats were gained by regarding the fat specific parameters. For example, filtration and dewatering of the waste fats proved necessary. The saturated fatty acids, most wanted for the production of cooling lubricants due to their high oxidation stability, were present in the range of 11,3% to 31,6%. Due to the low content of free fatty acids, a base catalysed process occurred more suitable for the transesterification of the waste edible fats. Trace analytical investigations concerning inorganic and organic pollutants proved a low basic contamination of the waste edible fats. Experiments with systematic contamination of the fats indicated an accumulation of the heavy metals in the glycerol phase during the transesterification process, whereas the organic pollutants were detected in the methylester fraction by amounts of 80% to 95%.

Outlook

In a next step, the further processing of the methylesters to monoesters with alcohols of the chain length C2 to C8 will be presented. Associated results of chemical-analytical investigations on the process and the application of the cooling lubricants will also be given.     

Speciation of Solutes in Drainage and Pore Waters of Two Former Lignite Mines (Germany)

An experimental speciation scheme consisting of ultra-filtration(1 kD), cation and anion exchange has been developed. Parallel calculations of the ion balances are performed using the computerroutine MINTEQA2. The experimental and computed ion balances suffer from non-equilibrium conditions, incalculability of metal-binding colloids or sub-colloids, inaccurate Eh measurements and analytical errors. In most samples colloidal or sub-colloidal structures of Fe oxy-hydroxides and/or gypsum influence the behavior of many trace elements. The comparison of theory and experiment has to be restricted to acid waters (pH < 5) where colloids (1–450 nm) and non-filterable colloids or sub-colloids (<1 nm) play a minor role. Yet, only a few transition metals such as Mn, Fe, Co, Ni, Cu, Zn, or Cd remain more or less free of colloidal influence in low pH waters. The effect of DOC on Al may be estimated by model substances like citrate.     

Effectiveness of amphibians as biodiversity surrogates in pond conservation

Amphibian decline has led to worldwide conservation efforts, including the identification and designation of sites for their protection. These sites could also play an important role in the conservation of other freshwater taxa. In 89 ponds in Switzerland, we assessed the effectiveness of amphibians as a surrogate for 4 taxonomic groups that occur in the same freshwater ecosystems as amphibians: dragonflies, aquatic beetles, aquatic gastropods, and aquatic plants. The ponds were all of high value for amphibian conservation. Cross‐taxon correlations were tested for species richness and conservation value, and Mantel tests were used to investigate community congruence. Species richness, conservation value, and community composition of amphibians were weakly congruent with these measures for the other taxonomic groups. Paired comparisons for the 5 groups considered showed that for each metric, amphibians had the lowest degree of congruence. Our results imply that site designation for amphibian conservation will not necessarily provide protection for freshwater biodiversity as a whole. To provide adequate protection for freshwater species, we recommend other taxonomic groups be considered in addition to amphibians in the prioritization and site designation process.