Bestimmung und Bewertung der Emissionen von PCDD/PCDF,PAK und kurzkettigen Aldehyden in den Brandgasen von Kerzen

Exhaust fumes of paraffin, beeswax and stearin candles without any further paint or decorative element were analysed for the toxicological important substance classes of PCDD/PCDF, PAH and short chain aldehydes. The candle waxes and wicks were investigated for chlorinated dioxins, furans and some known precursors. Toxicological risk assessment shows that emissions of the investigated candles are much lower than all administrative limitation values — even under “worst case conditions”. Thus, they do not produce a toxicological risk for human health.     

Gravity currents with double stratification: a numerical and analytical investigation

We consider high-Reynolds-number Boussinesq gravity current and intrusion systems in which both the ambient and the propagating “current” are linearly stratified. The main focus is on a current of fixed volume released from a rectangular lock; the height ratio of the fluids $H$ , the stratification parameter of the ambient $S$ , and the internal stratification parameter of the current, $\sigma $ , are quite general. We perform two-dimensional Navier–Stokes simulation and compare the results with those of a previously-published one-layer shallow-water model. The results provide insights into the behavior of the system and enhance the confidence in the approximate model while also revealing its limitations. The qualitative predictions of the model are confirmed, in particular: (1) there is an initial “slumping” stage of propagation with constant speed $u_N$ , after which $u_N$ decays with time; (2) for fixed $H$ and $S$ , the increase of $\sigma $ causes a slower propagation of the current; (3) for some combinations of the parameters $H,S, \sigma $ the fluid released from the lock lacks initially (or runs out quickly of) buoyancy “driving power” in the horizontal direction, and does not propagate like a gravity current. There is also a fair quantitative agreement between the predictions of the model and the simulations concerning the spread of the current.     

Demographic parameters of two populations of red coral (Corallium rubrum L. 1758) in the North Western Mediterranean

The demographic and reproductive structure of populations represents the main data set needed for conservation and management plans. Mediterranean red coral Corallium rubrum has been exploited for 2,000 years, but only recently management plans have been solicited by the international community. We examined and compared the demographic features of two red coral shallow populations located in distinct geographic locations: Portofino (Italy) and Cap de Creus (Spain). Adults and juveniles density, growth rates, population size and age structure, fecundity and fertility were examined. Juveniles were the dominant class (33 %) in both populations. The analysis of the gamete content of 653 colonies revealed that the populations have balanced sex ratios and similar fertility and polyp fecundity. The average annual growth rate, determined on 119 colonies by annual growth rings count, was similar in both populations (0.24 mm year^?1), decreasing with colony age. Maximum life span of 99 % of the colonies was 60 and 40 years at Portofino and Cap de Creus, respectively. Minimum harvestable size (7 mm basal diameter) was reached in 30–35 years, and the percentage of colonies above it was 6.7 % at Portofino and 2.1 % at Cap de Creus, where juvenile and adult colony densities were significantly lower and the percentage of commercial-sized colonies reduced by 25 % in just a few years. Notwithstanding similar growth and fecundity, the two populations showed different densities and size/age structures suggesting local factors, together with different fishing pressures, have to be taken into account in the management plans for this species.     

Writing it down: suggestions for a new approach towards understanding pro-environmental behaviour

A fashionable field of enquiry – the relationship between expressed attitudes and actual behaviour in the context of sustainable development – is complex (Staats et al. 2004 Staats, H, Harland, P and Wilke, H. 2004. Effecting durable change: a team approach to improve environmental behaviour in the household. Environ Behav., 36(3): 341–367. [Crossref], [Web of Science ®] , [Google Scholar]) and difficult to apply in a policy-relevant manner (Aall and Norland 2005 Aall, C and Norland, I. 2005. The use of the ecological footprint in local politics and administration: results and implications from Norway. Local Environ., 10(2): 159–172. [Taylor & Francis Online] , [Google Scholar]). However, recent research indicates that the use of a household diary can be beneficial in helping to quantify household environmental impact, in educating householders about their impact, and in identifying major ‘behavioural turning points’, where householders may focus efforts to reduce their environmental impact (Hunter et al. 2006 Hunter, C, Carmichael, K and Pangbourne, K. 2006. Household ecological footprinting using a new diary-based data-gathering approach. Local Environ, 11(3): 307–327. [Taylor & Francis Online] , [Google Scholar]). In other words, the use of a diary by householders is a potentially powerful tool in encouraging and facilitating desired behavioural change. This paper reports on the initial findings of an innovative study that assessed the use of a household diary approach as a means of framing and collecting household environmental data and, critically, as an educational vehicle for bringing about behavioural change. Based on the initial findings, it is clear that there is some potential to develop practical policy measures that empower householders by allowing them to better grasp their environmental impact and, consequently, recoup positive implications in terms of financial savings (e.g. reducing the amount of food thrown out) and health benefits (e.g. more walking/cycling).     

Passive scalar roughness lengths for atmospheric boundary layer flow over complex, fractal topographies

When modeling atmospheric boundary layer flow over rough landscapes, surface fluxes of flow quantities (momentum, temperature, etc.) can be described with equilibrium logarithmic law expressions, all of which require specification of a roughness length that is, physically, the elevation at which the flow quantity equals its surface value. In high Reynolds number flows, such as the atmospheric boundary layer, inertial forces associated with turbulent eddy motions are responsible for surface momentum fluxes (form, or pressure drag). Surface scalar fluxes, on the other hand, occur exclusively via diffusion in the immediate vicinity of the topography—the interfacial region—before being advected by turbulent eddy motions into the bulk of the flow. Owing to this difference in surface transfer mechanism, the passive scalar roughness length, $z_{0S}$ , is known to be less than the momentum roughness length, $z_0$ . In this work, classical relations are used to specify $z_{0S}$ during large-eddy simulation of atmospheric boundary layer flow over aerodynamically rough, synthetic, fractal topographies which exhibit power-law height energy spectrum, $E_h (k) \sim k^{\beta _s}$ , where $\beta _s$ is a (predefined) spectral exponent. These topographies are convenient since they resemble natural landscapes and $\beta _s$ can be varied to change the topography’s aerodynamic roughness (the study considers a suite of topographies with $-2.4 \le \beta _s \le -1.2$ , where $-2.4$ and $-1.2$ are the “most smooth” and “most rough” cases, respectively, corresponding with roughness Reynolds number, $Re_0 \approx 10$ and $300$ ). It is often assumed that $z_{0S}/z_{0} \approx 10^{-1}$ for all $Re_0$ . But results from this work show that the roughness length ratio, $z_{0S}/z_{0}$ , depends strongly on $Re_0$ , ranging between $10^{-3}$ and $10^{-1}$ .     

Gravity currents with tailwaters in Boussinesq and non-Boussinesq systems: two-layer shallow-water dam-break solutions and Navier–Stokes simulations

We consider the dam-break initial stage of propagation of a gravity current of density $\rho _{c}$ released from a lock (reservoir) of height $h_0$ in a channel of height $H$ . The channel contains two-layer stratified fluid. One layer, called the “tailwater,” is of the same density as the current and is of thickness $h_T (< h_0)$ , and the other layer, called the “ambient,” is of different density $\rho _{a}$ . Both Boussinesq ( $\rho _{c}/\rho _{a}\approx 1$ ) and non-Boussinesq systems are investigated. By assuming a large Reynolds number, we can model the flow with the two-layer shallow-water approximation. Due to the presence of the tailwater, the “jump conditions” at the front of the current are different from the classical Benjamin formula, and in some circumstances (clarified in the paper) the interface of the current matches smoothly with the horizontal interface of the tailwater. Using the method of characteristics, analytical solutions are derived for various combinations of the governing parameters. To corroborate the results, two-dimensional direct numerical Navier–Stokes simulations are used, and comparisons for about 80 combinations of parameters in the Boussinesq and non-Boussinesq domains are performed. The agreement of speed and height of the current is very close. We conclude that the model yields self-contained and fairly accurate analytical solutions for the dam-break problem under consideration. The results provide reliable insights into the influence of the tailwater on the propagation of the gravity current, for both heavy-into-light and light-into-heavy motions. This is a significant extension of the classical gravity-current theory from the particular $h_T=0$ point to the $h_T > 0$ domain.     

Thin-layer models for gravity currents in channels of general cross-section area,a review

We present a brief review of the recent investigations on gravity currents in horizontal channels with non-rectangular cross-section area (such as triangle, \(\bigvee \)-valley, circle/semi-circle, trapezoid) which occur in nature (e.g., rivers) and constructed environment (tunnels, reservoirs, canals). To be specific, we discuss the propagation of a gravity current (GC) in a horizontal channel along the horizontal coordinate x, with gravity g acting in the \(-z\) direction, and y the horizontal–lateral coordinate. The bottom and top of the channel are at \(z=0,H\). The “standard” problem is concerned with 2D flow in a channel with rectangular (or laterally unbounded) cross-section area (CSA). Recent investigations have successfully extended the standard knowledge to the channels of CSA given by the quite general \(-f_1(z)\le y \le f_2(z)\) for \(0 \le z \le H\). This includes the practical \(\bigvee \)-valley, triangle, circle/semi-circle and trapezoid; these geometries may be in “up” or “down” setting with respect to gravity, e.g., \(\bigtriangleup \) and \(\bigtriangledown \). The major objective of the extended theory is to predict the height of the interface \(z=h(x,t)\) and the velocity (averaged over the CSA) u(x, t), where t is time; the prediction includes the speed and position of the nose \(u_N(t), x_N(t)\). We show that the motion is governed by a set of simplified equations, called “model,” that provides versatile and insightful solutions and trends. The emphasis in on a high-Reynolds-number current whose motion is dominated by buoyancy–inertia balance; in particular a GC released from a lock, which also contains general effects such as front and internal jumps (shocks), and reflected bore. We discuss two-layer, one-layer, and box models; Boussinesq and non-Boussinesq systems; compositional and particle-driven cases; and the effect of stratification of the ambient fluid. The models are self-contained, and admit realistic initial and boundary conditions. The governing equations are amenable to analytical solutions in some special circumstances. Some salient features of the buoyancy-viscous regime, and the estimate for the length at which transition to this regime takes place, are also presented. Some experimental support to the theory, and open questions for further investigations, are also mentioned. The major conclusions are (1) The CSA geometry has significant influence on the motion of the GC; and (2) The new theory is a useful, very significant, extension of the standard two-dimensional GC problem. The standard current is just a particular case, \(f_{1,2} =\) constants, among many other covered by the new theory.     

Effects of algae-enriched rotifers on winter flounder (Pseudopleuronectes americanus) gene expression during metamorphosis

The aim of this study was to evaluate the effect of a dietary highly unsaturated fatty acid (HUFA) deficiency on winter flounder Pseudopleuronectes americanus metamorphosis by examining the growth and the expression of genes involved in some key metabolic processes: lipid digestion, oxidative stress, and growth. Three groups of fish were fed rotifers enriched with different blends of microalgae providing different HUFA profiles: (1) a diet comprising a mixture of three microalgae, Nannochloropsis oculata, Isochrysis galbana, and Pavlova lutheri (Cocktail diet), which contained a balanced combination of ecosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA); (2) the N. oculata diet (Nanno diet), with a low level of DHA; and (3) the I. galbana diet (Tiso diet), characterized by low levels of EPA and AA. The results indicate that the need for DHA increased from settlement and for EPA and AA from 15 days after settlement. The lower HUFA content in the Tiso and Nanno diets did not affect larval development or lipid reserve accumulation. The superoxide dismutase gene expression suggests a reduced oxidative stress in the Cocktail group, and overall results indicate that gh gene expression could be a valuable indicator of development at the molecular level in response to dietary HUFA quality during metamorphosis in winter flounder.     

Model selection criteria for overdispersed data and their application to the characterization of a host-parasite relationship

In the statistical modeling of a biological or ecological phenomenon, selecting an optimal model among a collection of candidates is a critical issue. To identify an optimal candidate model, a number of model selection criteria have been developed and investigated based on estimating Kullback’s (Information theory and statistics. Dover, Mineola, 1968) directed or symmetric divergence. Criteria that target the directed divergence include the Akaike (2nd international symposium on information theory. Akadémia Kiadó, Budapest, Hungary, pp 267–281, 1973, IEEE Trans Autom Control AC 19:716–723, 1974) information criterion, AIC, and the “corrected” Akaike information criterion (Hurvich and Tsai in Biometrika 76:297–307, 1989), AICc; criteria that target the symmetric divergence include the Kullback information criterion, KIC, and the “corrected” Kullback information criterion, KICc (Cavanaugh in Stat Probab Lett 42:333–343, 1999; Aust N Z J Stat 46:257–274, 2004). For overdispersed count data, simple modifications of AIC and AICc have been increasingly utilized: specifically, the quasi Akaike information criterion, QAIC, and its corrected version, QAICc (Lebreton et al. in Ecol Monogr 62(1):67–118 1992). In this paper, we propose analogues of QAIC and QAICc based on estimating the symmetric as opposed to the directed divergence: QKIC and QKICc. We evaluate the selection performance of AIC, AICc, QAIC, QAICc, KIC, KICc, QKIC, and QKICc in a simulation study, and illustrate their practical utility in an ecological application. In our application, we use the criteria to formulate statistical models of the tick (Dermacentor variabilis) load on a white-footed mouse (Peromyscus leucopus) in northern Missouri.     

Mass mortality and slow recovery of Diadema antillarum: Could compromised immunity be a factor?

Long-spined sea urchins (Diadema antillarum-a) began dying in January 1983 and over the next year virtually disappeared from the Caribbean. Decades later, Diadema densities remain low, with only very limited recovery in some areas. Ecological extinction of Diadema is a factor in the transformation of coral to barren algae-covered rock that has occurred in the Caribbean during the past 25 years. Working with sea urchins collected from St. Croix, United States Virgin Islands, we asked whether the immune system of Diadema differs from those of other common Caribbean urchins that did not experience the die-off. Using isolated coelomocytes, we tested humoral responses of the urchins with classic stimulators in numerous humoral immune assays. All coelomocytes responded to stimulators—with one notable and statistically significant exception—D. antillarum did not respond to lipopolysaccharide. Our results indicate that Diadema may have a weakness in its humoral defense response that is independent of local stressors and may help explain why Caribbean Diadema was vulnerable to the 1983 epidemic and has shown slow and limited recovery since then.     

Schwermetalle und organische Umweltchemikalien in Rehwild (Capreolus capreolus L.) aus Forst- und Agrarstandorten

The roe deer indicates the contamination of ecosystems with environmental chemicals. The influence of land use on the contamination of five different forest and agricultural ecosystems in Rheinland Pfalz was proven. The cadmium and lead content was measured in renal tissue of the roe deer. The organic chemicals PCB, α-HCH, Lindan, DDT, and DDE were investigated in kidneys and liver and correlated to adipose tissue. The following results have been obtained: Lead: The Pb-contamination was generally low in all ecosystems investigated. Cadmium: The Cd-values showed an area-dependend contamination of the organs. The data of the test organs from the forest sites and the semi-agricultural area were 2–4 times higher than the ZEBS-limit. The contamination of the animals corresponded to the wet deposition of Cd in the regions. σPCB: The PCB-results indicated a relativly high contamination of the ecosystems. The PCB-ZEBS-limit for the interior organs was surpassed in all areas.α-HCH, γ-HCH (Lindan): The uniformly low values of the HCH-group indicated that these compounds were probably not of ecotoxicological significance in the agricultural and forest regions.DDT, DDE: The results obtained showed a low background contamination in all ecosystems investigated. Areas with former high DDT-applications revealed higher values of DDE in the tissues. ZEBS: Central institution for the evaluation of chemicals in the environment (Bundesgesundheitsamt)     

Removal of sulfamethoxazole and trimethoprim from reclaimed water and the biodegradation mechanism

Sulfamethoxazole (SMX) and trimethoprim (TMP) are two critical sulfonamide antibiotics with enhanced persistency that are commonly found in wastewater treatment plants. Recently, more scholars have showed interests in how SMX and TMP antibiotics are biodegraded, which is seldom reported previously. Novel artificial composite soil treatment systems were designed to allow biodegradation to effectively remove adsorbed SMX and TMP from the surface of clay ceramsites. A synergy between sorption and biodegradation improves the removal of SMX and TMP. One highly efficient SMX and TMP degrading bacteria strain, Bacillus subtilis, was isolated from column reactors. In the removal process, this bacteria degrade SMX and TMP to NH ₄ ⁺ , and then further convert NH ₄ ⁺ to NO ₃ ^– in a continuous process. Microbial adaptation time was longer for SMX degradation than for TMP, and SMX was also able to be degraded in aerobic conditions. Importantly, the artificial composite soil treatment system is suitable for application in practical engineering.

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Identifying trophic relationships within the high Arctic benthic community: how much can fatty acids tell?

Multivariate analysis of fatty acids (FA) profiles proved to be a useful tool for demonstrating feeding preferences of Arctic invertebrates belonging to several taxonomic groups collected during summer and winter seasons in the Spitsbergen fjords (Arctic). Within phytodetrivorous taxa, the enhanced proportions of 16:1n-7, C16 polyunsaturated fatty acids (PUFA) and 20:5n-3 in crustaceans clearly reflected selective ingestion of diatoms, while high amounts of 22:6n-3 and C18 FAs found in molluscs indicated flagellate-based nutrition. High levels of C20 PUFA and 16:1n-7 together with the typical bacterial FAs were found in winter specimens of deposit-feeding polychaetes showing their reliance on highly reworked organic matter during this season. Our results suggest that 18:1n-9 may not be a reliable marker of carnivory feeding within benthic taxa. Lipid signatures of omnivores and carnivores/detrivores usually originated from a variety of dietary sources, of which few possess highly characteristic FA features. Still, elevated levels of Calanus markers (20:1 and 22:1 moieties) characterized species linked to the pelagic food chains, while 20:4n-6 proved to be a useful indicator of foraminiferan consumption. We highlight the need for a multimethod approach, since complexity of benthic food webs along with general lack of unambiguous FA trophic markers prevents tracking of trophic relationships with use of FA analysis alone. Based on their FA composition, we showed that benthic species represent a source of essential PUFA and could play a fundamental role in the Arctic food webs transferring energy derived from variable pelagic and benthic resources to upper trophic levels.     

Analyse von polycyclischen aromatischen Kohlenwasserstoffen (PAK)

An interlaboratory test was organized by the Allgemeine Unfallversicherungsanstalt, Dept. HUB (Department for the Prevention of Occupational Accidents and Diseases) for the analysis of polycyclic aromatic hydrocarbons (PAH). The aim of the test was to compare analytical results of serveral laboratories performing PAH analysis as routine work. In a preliminary study four different PAH-containing solutions were analyzed by independent laboratories in Germany and Austria. The concentrations of 17 PAH (according to the relevant NIOSH-methods) were to be determined. The results reveal the problems involved in the analysis of PAH.     

Effect of nitrogen source on short-term light and dark CO2 uptake by a marine diatom

Based on a series of short-term incubations involving the marine diatom Chaetoceros simplex (Bbsm), precultured in NH ₄ ⁺ -, NO ₃ ^- -and urea-limited continuous cultures at several dilution rates, we found that both the short-term specific rate of ¹⁴CO₂ uptake and the amount of CO₂ fixed after 8- and 16-min incubations were unaffected by enrichment with NH ₄ ⁺ , urea, or NO ₃ ^- when NH ₄ ⁺ or urea were the preconditioning forms of N, but were slightly suppressed when the cells were first grown on NO ₃ ^- . Similar enrichments in the dark, however, led to significant CO₂ uptake under all conditions of NH ₄ ⁺ enrichment and to similarly enhanced CO₂ uptake, but only at high growth rates, when urea was the source of enrichment nitrogen. Our light results are contrary to some contemporary findings, but there does seem to be agreement that photosynthetic rates of rapidly growing phytoplankton will not be affected by exposure to pulses of nitrogen. Enhanced dark uptake, in contrast, appears to be characteristic of phytoplankton under all degrees of N limitation, and, as such, may be useful as an “all or nothing” index of the nitrogen status of natural waters. There is some indication that the index may be useful in determining both the form of and the degree of N limitation as well.     

Physical and biological controls of algal blooms in the Río de la Plata

Coupled three-dimensional hydrodynamic and ecological numerical simulations were used to investigate the role of transport, stagnation zones and dispersion on inter-annual blooms of the diatom Aulacoseira sp. in the vicinity of the drinking water intakes of the Buenos Aires city (Argentina) in the upper Río de la Plata. Three different summer events were analyzed. First, a mild biomass bloom year (2006–2007), second, a high biomass bloom year (2007–2008) and third, a “normal” no bloom year (2009–2010). Simulated water height, water temperature, suspended solids and chlorophyll \(a\) concentrations patterns compared well with field data. Results revealed that the advection of phytoplankton cells via inflows to the Río de la Plata triggered Aulacoseira sp. blooms in the domain. In addition, excessive growth observed near the drinking water intakes, along the Argentinean margin, were associated with long retention times (stagnant region) and weak horizontal dispersion. Increased concentrations of suspended solids in the water column, in response to re-suspension events, did not prevent the blooms, however, were found to also play a key role in controlling the rate of phytoplankton growth. Finally, a non-dimensional parameter, R, that considers phytoplankton patch size, e-folding growth and dispersion time scales is shown to determine the potential bloom occurrences, as well as bloom intensity; R values higher than 5.7 suggest intense phytoplankton growth. For the mild biomass bloom year, \(R = 7.5\) , for the high biomass bloom year, \(R = 11\) and for the “normal” no bloom year \(R= 0.4\) .     

Die Photosynthehemmung pflanzlicher Protoplasten

The ecotoxicological effect of rain water on the light-dependent, photosynthetical oxygen production of suspended protoplasts from the bean speciesVicia faba L. was used for the characterization of airborne immissions. The protoplast-biotest — with rain water samples taken in an agricultural area from March to July — showed a clear inhibition of the photosynthetical oxygen production. Simultaneously, chemical analyses on some herbicides were carried out. The concentrations determined, however, did not sufficiently explain the measured inhibition of oxygen production; so, the toxicity yielded was assumed to result from not-analyzed compounds as well as synergistic and additive effects of the rain water constituents.     

Does temporal and spatial segregation explain the complex population structure of humpback whales on the coast of West Africa?

Humpback whales (Megaptera novaeangliae) in the Southeastern Atlantic Ocean (International Whaling Commission ‘Breeding Stock B’—BSB) are distributed from the Gulf of Guinea to Western South Africa. Genetic data suggest that this stock may be sub-structured, but it remains unknown if this is due to reproductive segregation. This paper evaluates the spatial and temporal population structure of BSB humpback whales using a combination of maternally and bi-parentally inherited markers. The genetic differentiation that we identify in this study could be due to a combination of (1) spatial and/or temporal segregation on breeding grounds in the greater Gulf of Guinea, (2) the possibility of maternally inherited site fidelity to specific feeding grounds and (3) the use of two generalized but exclusive migratory routes (coastal and offshore) between feeding and breeding areas. Further, photo-identification and genetic sampling efforts in other areas of the Sub-Saharan Western Africa winter range and targeted deployment of satellite tags would help to clarify some of the apparent complexity in the population structure of animals biopsied in this region.     

Fine-scale genetic structure in the surface brooding Caribbean octocoral,Antillogorgia elisabethae

Larval dispersal is a critical component of marine species’ life histories because it controls their population dynamics. Dispersal distance can be inferred by the presence and scale of spatial genetic structure (SGS). The larvae of Antillogorgia elisabethae, a surface brooding Caribbean octocoral, have been observed to settle within meters of maternal colonies, although many disperse over greater distances. Using a spatially hierarchical sampling design, A. elisabethae recruits were collected from a site off the coast of Great Abaco, The Bahamas, in June of 2009–2011. Seven microsatellite loci were used to determine whether genetic structure was present among recruits on scales of <1 m to 10s of meters. Multilocus genotypes were autocorrelated within spatial distance classes using Moran’s I coefficient as an estimate of genetic similarity, and Rousset’s genetic distance (â). Genetic structure was present on a scale of <10 m in 2010, but not in the other 2 years, suggesting that larval dispersal was more localized in 2010. Moran’s I coefficients were positive and significant for 0–1, 1–2 and 2–5 m classes in 2010, and the average genetic distance (â) among recruits in the 0–1 m class was significantly lower than the other classes. Autocorrelograms suggested that genetic patch sizes were 7.5 m in 2010, and 20 m in 2009 and 2011. Differences in the SGS of recruits between years might reflect temporal variation in temperature, wind and/or current speeds affecting larval dispersal, or variation in reproduction at the site.