Second german heavy-metal survey by means of mosses,and comparison of the first and second approach in germany and other european countries

This paper shows the geographic distribution in Germany of iron (Fe), nickel (Ni) and lead (Pb) analyzed in mosses in 1995/96 and compares it with the results of the 1990/91 pilot study within a European moss-monitoring programme. Other elements (As, Cd, Cr, Cu, Ti, V, Zn) are compared on basis of the overall element medians for Germany of the 1990/91 and 1995/96 survey. Samples of Pleurozium schreberi, Scleropodium purum, Hypnum cupressiforme and Hylocomium splendens were taken at a total of 1026 sites. In the 1995/96 monitoring campaign, 95% of the original sites of the 1990/91 study were resampled. The results from 1995/96 display local elevated values and many cases of areas affected by known sources of heavy-metal emissions. The industrialized and urban regions of Germany are shown up clearly by the 1995/96 moss-monitoring results: the Ruhr area, parts of Saarland and Baden-Württemberg, as well as areas in eastern Germany. Relatively low values for many elements were found in large areas of Lower Saxony and Bavaria. A comparison of the results of the 1990/91 and 1995/96 moss-monitoring programmes shows a fall in the concentration of the presented elements (except cadmium, copper and zinc) over the relevant period. Especially in the former GDR, chromium (Cr), iron (Fe), titanium (Ti) and vanadium (V) decreased significantly. This is, firstly, a reflection of the closure of and/or technological improvements to large power plants; secondly it is due to the fact that lignite has given way to other fuels. Vanadium (V) and nickel (Ni), typical constituents of crude oil, also show a decrease in the western part and thus document changes in the type of fuel consumed. The significant fall in lead concentration in 1995/96 as compared to 1990/91 in what used to be East and West Germany probably results from the increasing use of lead-free petrol. A comparison of the median values for 1990/91 and 1995/96 in mosses to the rate of emission of heavy metals in Germany for 1990 and 1995 shows similar trends in the case of elements such as arsenic (As), chromium (Cr), nickel (Ni), and lead (Pb). The comparison of the medians of the elements analyzed for 19 European countries indicates for most of the elements a general tendency to lower values in 1995, except for Lithuania, Netherlands, Portugal, Italy and United Kingdom.     

The Arctic pteropod<Emphasis Type="Italic"> Clione limacina</Emphasis>: seasonal lipid dynamics and life-strategy

During various seasons from May 2001 until July/August 2003, the lipid dynamics of the pteropod Clione limacina from Kongsfjorden, Svalbard, were investigated with respect to ontogenetic development and life-cycle. Polytrochous larvae, which were dominant in spring (April, May), composed the lipid-richest specimens of the population, with total lipid of about 50% of dry mass (%DM). Major lipid classes were triacylglycerols (TAG) and 1-O-alkyldiacylglycerol ethers (DAGE), accounting on average for 53.1 and 21.9% of total lipid, respectively. Until summer, larvae grew to adults by utilising their storage lipids. In July/August, lipids were depleted to about 10%DM due to maturation and reproduction. Almost all animals in autumn (September) were mature and able to replenish their lipid deposits by accumulating DAGE (26.7%) and TAG (39.6%). This is probably the prerequisite for successful overwintering.Principal component analysis (PCA), based on the fatty acid compositions, revealed ontogenetic differences between polytrochous larvae, and small and full-grown adults. Higher proportions of 18:4(n-3) and 14:0 were found in polytrochous larvae and smaller adults during spring. Both fatty acids were highly significantly correlated with the proportions of TAG, which were used for growth and development because they are presumably easier to metabolise. PCA also divided C. limacina specimens into DAGE-rich and DAGE-poor. We suggest that DAGE are a long-term energy store and hypothesise that they are necessary during periods of food scarcity, but may also serve as an energy source for reproduction. The fatty acids 17:1(n-8), 15:0, 16:1(n-7) and 18:1(n-7) were significantly correlated with the proportion of DAGE but not with TAG. These fatty acids, which do not originate from their only prey, Limacina helicina, are synthesised de novo. Their abundance reflects an efficient lipid production by C. limacina. Based on the results of lipid biosynthesis and accumulation in combination with the population structure, we suggest that C. limacina has at least a 2-year life-cycle in Svalbard waters.Communicated by M. Kühl, Helsingør     

Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows. Part I: Single Round Jet

The mechanics of buoyant jet flows issuing with a general three-dimensional geometry into an unbounded ambient environment with uniform density or stable density stratification and under stagnant or steady sheared current conditions is investigated. An integral model is formulated for the conservation of mass, momentum, buoyancy and scalar quantities in the turbulent jet flow. The model employs an entrainment closure approach that distinguishes between the separate contributions of transverse shear (leading to jet, plume, or wake internal flow dynamics) and of azimuthal shear mechanisms (leading to advected momentum puff or thermal flow dynamics), respectively. Furthermore, it contains a quadratic law turbulent drag force mechanism as suggested by a number of recent detailed experimental investigations on the dynamics of transverse jets into crossflow. The model is validated in several stages: First, comparison with basic experimental data for the five asymptotic, self-similar stages of buoyant jet flows, i.e., the pure jet, the pure plume, the pure wake, the advected line puff, and the advected line thermal, support the choice and magnitude of the turbulent closure coefficients contained in the entrainment formulation. Second, comparison with many types of non-equilibrium flows support the proposed transition function within the entrainment relationship, and also the role of the drag force in the jet deflection dynamics. Third, a number of spatial limits of applicability have been proposed beyond which the integral model necessarily becomes invalid due to its parabolic formulation. These conditions, often related to the breakdown of the boundary layer nature of the flow, describe features such as terminal layer formation in stratification, upstream penetration in jets opposing a current, or transition to passive diffusion in a turbulent ambient shear flow. Based on all these comparisons, that include parameters such as trajectories, centerline velocities, concentrations and dilutions, the model appears to provide an accurate and reliable representation of buoyant jet physics under highly general flow conditions.     

Pheromone-based aggregation behaviour of the firebrat, <Emphasis Type="Italic">Thermobia domestica</Emphasis> (Packard) (Thysanura: Lepismatidae)

Summary. We tested the hypothesis that aggregation behaviour of the firebrat, Thermobia domestica (Packard) (Thysanura: Lepismatidae), an inhabitant of enclosed microhabitats, is mediated, at least in part, by a pheromone. Individual insects were released into the central chamber of a 3-chambered olfactometer and test stimuli were placed in lateral chambers. Paper discs previously exposed for 3 days to 10 female, male, or juvenile T. domestica were all preferred by female, male, or juvenile T. domestica over unexposed paper discs, indicating the presence of an aggregation/arrestment pheromone. In additional experiments, frass and scales from female T. domestica, tested singly and in combination, proved not to be the source of the pheromone. Physical contact was required for pheromone recognition, indicating that the pheromone arrests rather than attracts conspecifics. Arrestment by the long-tailed silverfish, Ctenolepisma longicaudata Escherich (Thysanura: Lepismatidae), but not by the common silverfish, Lepisma saccharina L. (Thysanura: Lepismatidae), to T. domestica exposed paper discs suggests closer phylogenetic relatedness between C. longicaudata and T. domestica, than between C. longicaudata and L. saccharina. Whether C. longicaudata or L. saccharina produce an aggregation signal, and whether T. domestica respond to this signal is unknown. Received 10 June 2002; accepted 30 September 2002.