Sources of airborne CC14

Atmospheric mixing ratios of chlorinated C₁ and C₂ hydrocarbons (CHCs) were measured at the mountain Wank (Garmisch-Partenkirchen, Bavarian Alps) in autumn 1992. The data lead to the assumption that at least part of the observed CC1₄ originates from a source different to the other CHCs measured (C₂HCL₃, C₂C1₄, CHCl₃ and CH₃CCl₃). The nature of this source is discussed.     

Adsorption anionischer Azofarbstoffe an Boden/Sediment

The adsorption behavior of three anionic azo dyes (Acid Orange 6, Acid Orange 10 andAcid Orange 12) on different soil/sediment components (quartz sand, clay and organic matter) was investigated with a flow-through method using a simplified HPLC apparatus. Organic matter had the highest adsorption capacity for all three dyes, followed by clay and sand. The adsorption on different components in mixtures was not additive. The adsorption of similar aniomic azo dyes decreased with increasing negative charge. The affinity of equally charged dye molecules to the adsorbents was also strongly influenced by the remaining chemical structure. While adsorption on organic matter could always be described by Freundlich isotherms, S-shaped isotherms were often measured with quartz sand and clay. For that reason one must assume different adsorption mechanisms for organic matter and mineral adsorbens. Lower pH values always led to stronger adsorption of the anionic azo dyes. On the other hand, ionic strength effects cannot be characterized so clearly. Adsorption was generally lowered by decreasing ionic strengths but sometimes the opposite effect was observed. Moreover, there were some unusual cases of partly irreversible adsorption on quartz sand and organic matter when the dyes were not dissolved in an aqueous solution containing additional inorganic ions but in double distilled water. The adsorption of anionic azo dyes on soil and sediment materials turned out to be a very complex process. Although some interesting coherences could be pointed out, much more research is required to recognize general principles, concerning for example the influence of the chemical structure or the surrounding aqueous solution.     

Complementary effect of natural and sexual selection against immigrants maintains differentiation between locally adapted fish

Adaptation to ecologically heterogeneous environments can drive speciation. But what mechanisms maintain reproductive isolation among locally adapted populations? Using poeciliid fishes in a system with naturally occurring toxic hydrogen sulfide, we show that (a) fish from non-sulfidic sites (Poecilia mexicana) show high mortality (95 %) after 24 h when exposed to the toxicant, while locally adapted fish from sulfidic sites (Poecilia sulphuraria) experience low mortality (13 %) when transferred to non-sulfidic water. (b) Mate choice tests revealed that P. mexicana females exhibit a preference for conspecific males in non-sulfidic water, but not in sulfidic water, whereas P. sulphuraria females never showed a preference. Increased costs of mate choice in sulfidic, hypoxic water, and the lack of selection for reinforcement due to the low survival of P. mexicana may explain the absence of a preference in P. sulphuraria females. Taken together, our study may be the first to demonstrate independent—but complementary—effects of natural and sexual selection against immigrants maintaining differentiation between locally adapted fish populations.     

Evolutionary developmental biology: its concepts and history with a focus on Russian and German contributions

Evolutionary theory has been likened to a “universal acid” (Dennett 1995) that eats its way into more and more areas of science. Recently, developmental biology has been infused by evolutionary concepts and perspectives, and a new field of research—evolutionary developmental biology—has been created and is often called EvoDevo for short. However, this is not the first attempt to make a synthesis between these two areas of biology. In contrast, beginning right after the publication of Darwin’s Origin in 1859, Ernst Haeckel formulated his biogenetic law in 1872, famously stating that ontogeny recapitulates phylogeny. Haeckel was in his turn influenced by pre-Darwinian thinkers such as Karl Ernst von Baer, who had noted that earlier developmental stages show similarities not seen in the adults. In this review, written for an audience of non-specialists, we first give an overview of the history of EvoDevo, especially the tradition emanating from Haeckel and other comparative embryologists and morphologists, which has often been neglected in discussions about the history of EvoDevo and evolutionary biology. Here we emphasize contributions from Russian and German scientists to compensate for the Anglo-American bias in the literature. In Germany, the direct influence of Ernst Haeckel was felt particularly in Jena, where he spent his entire career as a professor, and we give an overview of the “Jena school” of evolutionary morphology, with protagonists such as Oscar Hertwig, Ludwig Plate, and Victor Franz, who all developed ideas that we would nowadays think of as belonging to EvoDevo. Franz ideas about “biometabolic modi” are similar to those of a Russian comparative morphologist that visited Jena repeatedly, A. N. Sewertzoff, who made important contributions to what we now call heterochrony research—heterochrony meaning changes in the relative timing of developmental events. His student I. I. Schmalhausen became an important contributor to the synthetic theory of evolution in Russia and is only partly known outside of the Russian-reading world because only one of his many books was translated into English early on. He made many important contributions to evolutionary theory and we point out the important parallels between Schmalhausen’s ideas (stabilizing selection, autonomization) and C. H. Waddington’s (canalization, genetic assimilation). This is one of the many parallels that have contributed to an increased appreciation of the internationality of progress in evolutionary thinking in the first half of the twentieth century. A direct link between German and Russian evolutionary biology is provided by N. V. Timoféeff-Ressovsky, whose work on, e.g., fly genetics in Berlin is a crucial part of the history of evo-devo. To emphasize the international nature of heterochrony research as predecessor to the modern era of EvoDevo, we include Sir G. R. de Beer’s work in the UK. This historical part is followed by a short review of the discovery and importance of homeobox genes and of some of the major concepts that form the core of modern EvoDevo, such as modularity, constraints, and evolutionary novelties. Major trends in contemporary EvoDevo are then outlined, such as increased use of genomics and molecular genetics, computational and bioinformatics approaches, ecological developmental biology (eco-devo), and phylogenetically informed comparative embryology. Based on our survey, we end the review with an outlook on future trends and important issues in EvoDevo.     

Establishing best practice for microbially aided phytoremediation

The dispersal of industrial and municipal wastes leads to an increase of contaminated soils and is one of the large concerns in many countries throughout Europe regarding environmental issues. This article proposes a sequence of the microbially aided phytoremediation (phytoextraction and phytostabilization) procedure with the following most important steps: (1) risk assessment, (2) site investigation, (3) determination of the remediation strategy, (4) realization of remediation measures, (5) monitoring, and (6) reuse of the remediated site. UMBRELLA's innovative approach is a proposal of methods to evolve a tool-box which supports phytoremediation by means of microbes and enhances the efficiency of the remediation process at low and heterogeneously metal contaminated sites.     

Scale invariant measures of pattern intensity and grain: A simulation experiment

We propose new dimensionless and scale-invariant measures for detection of pattern intensity, defined as the level of aggregation of individuals regardless their kind, and pattern grain, the level of segregation among individuals of at least two different kinds in point-pattern spatial data using tessellation methodology. Both real and simulated data on spatial distribution of plants in ecological communities show that the proposed parameters can be considered fingerprints of particular point patterns. This approach allows definition of both pattern intensity and grain for any kind of tessellated plane in an operational way, rendering these available for quantification and testing.     

Zur Problematik der Anwendung von Hintergrundwerten beim Vollzug des Bodenschutzrechts

The knowledge about background levels of heavy metals in soils is essential for the use of the precautionary values for heavy metals as provided by the German Soil-Protection-Act. In the northeast of Bavaria the 90th percentiles in the back-ground levels of heavy metals in the soil exceed the precautionary values in many cases. Background levels were determined separately for soils of different parent materials of rocks, soil horizons and land use (agricultural or forest soils), with the parent material of rock having the strongest influence on the content of heavy metals in different soils. Precautionary values are highly exceeded by chrome and nickel in basic and ultrabasic rocks. High variability of heavy metal contents was found even in soils of the same parent material (C-horizons), which is due to the natural geochemical variability of rocks and the mixing of different parent materials during the Pleistocene. For an effective use of the German Soil-Protection-Order, areas must be defined where the probability is high that the 90th percentiles of the background levels of heavy metals exceed the precautionary values. It has to be determined, how the risk of mobilisation of heavy metals can be estimated within these areas and what has to be done if heavy metal contents in soils exceed not only the precautionary values but also the background levels.     

Aerosol Generation by Bubble Collapse at Ocean Surfaces

Sea salt particles are part ofmarine aerosols in the troposphere. A fraction ofthese particles is released by droplets generatedduring the bursting of bubbles at the ocean surface.Droplets result from fragmentation of film caps (filmdroplets) and the disintegration of water jets formedsubsequent to the bubble collapse (jet droplets).This release process is also of importance fortechnical applications and, consequently, simulationtools have been developed, which now may be used toquantify the contribution of these effects to marineaerosol generation. To calculate the amount of filmdroplets generated, it is necessary to determine thevolume of the film cap, which is a function of itsthickness and surface area. While surface areas ofsmall bubbles can be determined by an analyticalsolution of a simplified balance of forces, shapes oflarge non-spherical bubbles are calculatednumerically. The determination of the film thicknessis based on a resonance model for bubbleoscillations. For a detailed analysis of the jetdroplet generation, the bubble burst induced jetformation and disintegration is simulated numericallyusing a SOLA-MAC algorithm.     

Ubiquitous eight-carbon volatiles of fungi are infochemicals for a specialist fungivore

An enormous variety of volatile substances are released in distinctive blends by fungal substrates that should be recognisable for fungivores. Certain compounds dominate in most of the fungal species. Fungal oxylipins as the eight-carbon volatiles are the most prominent. This raises the question whether such are specific enough to qualify as appropriate host cues for a fungivore. We could demonstrate differentiated responses of the fungivorous beetle Bolitophagus reticulatus to eight-carbon volatiles: Nine eight-carbon volatiles were identified with GC–MS from its host fungus Fomes fomentarius. 1-Octen-3-ol, 3-octanone and 3-octanol induced contrasting behaviour of beetles in olfactometer bioassays. Electroantennographic experiments investigating the beetle olfactory sense revealed distinguishable antennal responses. Moreover, their individual release from F. fomentarius fruiting bodies changes not only considerably, but also independently over successive stages of beetle colonisation. Concentrations of attractive and repellent eight-carbon volatiles correlate to frequency of beetles in the field and further substantiate their relevance as host cues. Our results show that a specialist fungivore is able to differentiate the most common eight-carbon volatiles of fungi to assess host quality. Key roles and marked similarities of fungal to plant oxylipins suggest a comparable importance of eight-carbon volatiles to fungivores as green leaf volatiles have to herbivores.