Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus

A specimen of the horned dinosaur Psittacosaurus from the early Cretaceous of China is described in which the integument is extraordinarily well-preserved. Most unusual is the presence of long bristle-like structures on the proximal part of tail. We interpret these structures as cylindrical and possibly tubular epidermal structures that were anchored deeply in the skin. They might have been used in display behavior and especially if one assumes that they were colored, they may have had a signal function. At present, there is no convincing evidence which shows these structures to be homologous to the structurally different integumentary filaments of theropod dinosaurs. Independent of their homology, however, the discovery of bristle-like structures in Psittacosaurus is of great evolutionary significance since it shows that the integumentary covering of at least some dinosaurs was much more complex than has ever been previously imagined.     

Brominated flame retardants and organochlorine pollutants in eggs of little owls (Athene noctua) from Belgium

Residues of brominated diphenylethers (PBDEs), organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in 40 eggs of little owls (Athene noctua), a terrestrial top predator from Belgium. The major organohalogens detected were PCBs (median 2,600 ng/g lipid, range 790-23 000 ng/g lipid). PCB 153,138/163, 170, 180 and 187 were the predominant congeners and constituted 71% of total sum PCBs. PBDEs were measurable in all samples, but their concentrations were much lower than for PCBs, with a range from 29-572 ng/g lipid (median 108 ng/g lipid). The most prevalent PBDE congeners in little owl egg samples were BDE 47, 99 and 153. This profile differs from the profile in marine bird species, for which BDE 47 was the dominant congener, indicating that terrestrial birds may be more exposed to higher brominated BDE congeners than marine birds. The fully brominated BDE 209 could be detected in one egg sample (17 ng/g lipid), suggesting that higher brominated BDEs may accumulate in terrestrial food chains. Brominated biphenyl (BB) 153 was determined in all egg samples, with levels ranging from 0.6 to 5.6 ng/g lipid (median 1.3 ng/g lipid). Additionally, hexabromocyclododecane (HBCD) could be identified and quantified in only two eggs at levels of 20 and 50 ng/g lipid. OCPs were present at low concentrations, suggesting a rather low contamination of the sampled environment with OCPs (median concentrations of sum DDTs: 826 ng/g lipid, sum chlordanes: 1,016 ng/g lipid, sum HCHs: 273 ng/g lipid). Hexachlorobenzene (HCB) and octachlorostyrene (OCS) were also found at low median levels of 134 and 3.4 ng/g lipid, respectively. Concentrations of most analytes were significantly higher in eggs collected from deserted nests in comparison to addled (unhatched) eggs, while eggshell thickness did not differ between deserted and addled eggs. No significant correlations were found between eggshell thickness and the analysed organohalogens.     

The Biological System of the Elements (BSE)--a brief introduction into historical and applied aspects with special reference on "ecotoxicological identity cards" for different element species (e.g. As and Sn)

There are different methods to estimate and predict effects of chemical elements and corresponding speciation forms in biochemistry and toxicology, including statements on essentiality and antagonisms. Two approaches are given here: (1) "identity cards" describing biologically fundamental aspects of element chemistry and (2) qualitative discussions which assume the existence of (indirect ways into) chemical autocatalysis to be essential for maintaining life and permitting reproduction. The latter method, developed by the present authors, draws upon Stoichiometric Network Analysis, a safe procedure for complexity reduction in feedback networks) and provides estimates of concentration regimes for different elements suitable for survival and reproduction. The biochemical hierarchy level considered here is that of (metallo-)proteins. Thermodynamic toxicity aspects are given in correlations with DMSO solvent affinities and thiocyanate bonding modes. Effects of antagonists and of ion substitution within metalloenzymes or of metabolic simplification can be dealt with, likewise increased sensitivities within symbiotic relationships and within carcinomas are explained which are relevant for environmental monitoring and tumour therapy, respectively.     

Uptake of terbuthylazine and its medium polar metabolites into maize plants

The uptake of terbuthylazine and its medium polar metabolites into maize plants under outdoor conditions is investigated. For this purpose, a dynamical fate model consisting of soil, plant and air is developed. The model calculations are compared with experimental results of outdoor lysimeter tests, carried out with¹⁴C-labelled herbicide applied to sandy agricultural soil at a single application rate of 890 g/ha. Approximately 0.3 % of the applied activity remains in all the plants after the vegetation period. The model predicts that about three times that amount is volatilized from the plants into the air. Activity uptaken from soil and volatilized from plant surface into air is predominately associated with metabolites. During the whole vegetation period the fraction of unchanged terbuthylazine in the plants is very small (less than 1 % of the extractable activity).     

Uptake of Tributyltin into Willow Trees

BACKGROUND: Organotins have been used world-wide as antifoulants in ship paints. Repeatedly, severe effects on aquatic species have resulted. The use of organotins for this purpose was ruled out, and dumping of contaminated harbor sludge into the sea was prohibited. Land-based dumping is seen as an alternative. OBJECTIVE: This study investigates sorption, uptake and translocation of tributyltin (TBT) to willow trees in order to evaluate phytoremediation as treatment option. The study considers the influence of pH on the plant uptake of organotins. EXPERIMENTAL SET-UP: Chemicals investigated were the weak base tributyltin chloride (TBTCl) and the neutral tributyltin hydride (TBTH). Organotins were extracted from solution and plant material with toluene, and analyzed as tin by AAS with graphite oven. The pH in solution varied from pH 4 to pH 7. The sorption to living and dead roots, stems and leaves was measured in shaking experiments. The uptake into intact trees was measured at nominal levels of 1 and 10 mg TBT/l for TBTH and TBTCl at low and high pH. RESULTS: The sorption to roots and leaves dropped for dead tissue, but did not vary much with pH. The sorption to stems increased for dead stems and with pH. The solubility of TBTCl in water was below 10 mg/l and lowest at pH 4. Concentrations of TBTCl and TBTH in solutions with trees dropped rapidly to low values. Highest TBT contents in trees were found in roots and lower stems. The concentrations followed the concentrations in solution. The pH had only a small effect on the plant uptake of TBTCl, and no effect on the uptake of TBTH. No effective translocation to higher stems or leaves was found. DISCUSSION: An ion trap mechanism that accumulates the weak base TBTCl in the xylem sap of plants and leads to upward translocation could not be detected. Neither TBTCl at low or high pH, nor the neutral lipophilic chemical TBTH, were translocated effectively to leaves. The TBT+ cation sorbed strongly to plant tissue. The exact mechanism for the strong sorption of the cation is unknown, but similar effects have been observed for algae, liposomes and isolated biomembranes. CONCLUSIONS: Both the uptake of the neutral TBTH and the uptake of the neutral molecule form of TBTCl into willows was as is to be expected from theory. The cation TBT+ showed an unexpected behavior which has been observed before. No ion trap occurs, and the phytoextraction of TBT is not feasible. OUTLOOK: Planting trees, or other appropriate vegetation, could have a beneficial remediation effect by aeration of the TBT-contaminated soil or sludge. In a follow-up paper, the toxicity of TBT to willow trees will be described.     

Water and nitrate fluxes at a forest site in the North Tyrolean Limestone Alps

The water balance for the site Mühleggerköpfl in the North Tyrolean Limestone Alps has been established to a soil depth of 50 cm. The evaporation amounts to 42% and deep percolation is 58 % of the precipitation. The surface runoff was negligible and therefore the according nitrate fluxes as well. Soil water analysis revealed mean nitrate concentrations of 3 to 15 mg NO₃ L⁻¹, depending on soil depth. The nitrate concentrations at 50 cm soil depth and the associated percolation rates led to NO₂ ⁻N outputs of 15.9 kg NO₃ ⁻N ha⁻¹ in the year 1999 and 7.9 kg NO₃ ^∼N ha⁻¹ in the year 2000.

     

Transport of nitrogen oxides, carbon monoxide and ozone to the Alpine Global Atmosphere Watch stations Jungfraujoch (Switzerland), Zugspitze and Hohenpeissenberg (Germany), Sonnblick (Austria) and Mt. Krvavec (Slovenia)

The Alpine stations Zugspitze, Hohenpeissenberg, Sonnblick, Jungfraujoch and Mt. Krvavec contribute to the Global Atmosphere Watch Programme (GAW) of the World Meteorological Organization (WMO). The aim of GAW is the surveillance of the large-scale chemical composition of the atmosphere. Thus, the detection of air pollutant transport from regional sources is of particular interest. In this paper, the origin of NO_x (measured with a photo-converter), CO and O₃ at the four Alpine GAW stations is studied by trajectory residence time statistics. Although these methods originated during the early 1980s, no comprehensive study of different atmospheric trace gases measured simultaneously at several background observatories in the Alps was conducted up to present.The main NO_x source regions detected by the trajectory statistics are the northwest of Europe and the region covering East Germany, Czech Republic and southeast Poland, whereas the main CO source areas are the central, north eastern and eastern parts of Europe with some gradient from low to high latitudes. Subsiding air masses from west and southwest are relatively poor in NO_x and CO.The statistics for ozone show strong seasonal effects. Near ground air masses are poor in ozone in winter but rich in ozone in summer. The main source for high ozone concentration in winter is air masses that subside from higher elevations, often enhanced by foehn effects at Hohenpeissenberg. During summer, the Mediterranean constitutes an important additional source for high ozone concentrations.Especially during winter, large differences between Hohenpeissenberg and the higher elevated stations are found. Hohenpeissenberg is frequently within the inversion, whereas the higher elevated stations are above the inversion.Jungfraujoch is the only station where the statistics detect an influence of air rich in CO and NO_x from the Po Basin.