Are Declines in North American Insectivorous Songbirds Due to Causes on the Breeding Range?

Previous studies have reported a recent decline in breeding populations of migratory songbirds in eastern and central North America. Several explanations have been suggested: deforestation on the wintering grounds in the tropics and habitat loss, increased predation pressure, and increased cowbirds parasitism on the breeding range. We used these factors to assign 47 species of insectivorous passerines to groups with contrasting vulnerability, and then used the North America Breeding Bird Survey to analyze population trends in these groups on a large continental scale. Variables indexing susceptibility to predation on the breeding ground were most strongly correlated with population trends form 1968 to 1987. During the period from 1978 to 1987, migratory status was also significantly associated with population trends long-distance migrants to the neotropics exhibited a small, nonsignificant decreasing trend, whereas residents and short-distance migrants increased strongly. During the same time period, the group of species with low nest location, open nest, and high cowbird parasitism declined significantly. Although it is difficult to separate the effects of multiple factors, our analyses suggest that predation on the breeding ground in North America has played a larger role in the decline of migratory songbirds than deforestation on the wintering grounds in the tropics.     

Multivariate data analysis of organochlorines and brominated flame retardants in Baltic Sea guillemot (Uria aalge) egg and muscle

Concentrations of organochlorines (OCs) and brominated flame-retardants (BFRs) were determined in guillemot (Uria aalge) eggs from the island of Stora Karls? in the Baltic Sea where 10 eggs/year were collected in the years 2000, 2001 and 2002. The dominating contaminant in egg was p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) with a geometric mean (GM) concentration of 18200 ng/g lipid weight (lw). The GM concentration in egg of hexabromocyclododecane (HBCD) of 140 ng/glw, was significantly higher than that of polybrominated diphenyl ether (summation operatorPBDE) of 77 ng/glw. For the evaluation of the data multivariate data analysis techniques namely principal components analysis (PCA), partial least squares regression (PLS), soft independent modelling of class analogy (SIMCA classification), and PLS discriminant analysis (PLS-DA), were used. We investigated whether the eggs' biological characteristics co-varied with egg concentrations of OCs and BFRs, and found e.g., significant negative correlations between egg weight and concentrations of HCB and p,p'-DDE. A PLS model with analyzed BFRs as the Y matrix and OCs as the X matrix could, with varying accuracy, calculate the concentrations of BFRs in the individual egg from their concentrations of OCs (e.g., R(2)Y of 0.89 for BDE47, and of 0.50 for HBCD). Lastly, we compared the contaminant concentrations in the eggs to those in previously analyzed pectoral muscles from adult guillemots from Stora Karls?, from the year 2000. A PLS-DA model, showed that some of the contaminants (e.g., HBCD and CB28) had significantly higher concentrations in egg than in muscle, although 7 of the 14 contaminants showed no difference in concentrations between the two matrices.     

Comprehensive prenatal diagnostics: Exome versus genome sequencing

Objective

This study aimed to assess the diagnostic yield of prenatal genetic testing using trio whole exome sequencing (WES) and trio whole genome sequencing (WGS) in pregnancies with fetal anomalies by comparing the results with conventional chromosomal microarray (CMA) analysis.

Methods

A total of 40 pregnancies with fetal anomalies or increased nuchal translucency (NT ≥ 5 mm) were included between the 12th and 21st week of gestation. Trio WES/WGS and CMA were performed in all cases.

Results

The trio WES/WGS analysis increased the diagnostic yield by 25% in cases with negative CMA results. Furthermore, all six chromosomal aberrations identified by CMA were independently detected by WES/WGS analysis. In total, 16 out of 40 cases obtained a genetic sequence variant, copy number variant, or aneuploidy explaining the phenotype, resulting in an overall WES/WGS diagnostic yield of 40%. WES analysis provided a more reliable identification of mosaic sequence variants than WGS because of its higher sequencing depth.

Conclusions

Prenatal WES/WGS proved to be powerful diagnostic tools for fetal anomalies, surpassing the diagnostic yield of CMA. They have the potential to serve as standalone methods for prenatal diagnosis. The study highlighted the limitations of WGS in accurately detecting mosaic variants, which is particularly relevant when analyzing chorionic villus samples.     

Levels and trends of persistent organic pollutants in ringed seals (Phoca hispida) from Central West Greenland, with particular focus on polybrominated diphenyl ethers (PBDEs)

Polybrominated diphenyl ethers (PBDEs) and the organochlorine compounds polychlorinated biphenyls (PCBs), DDTs, HCB, chlordane-related pesticides, HCH and toxaphene were analysed in blubber of juvenile ringed seals from Central West Greenland collected between 1982 and 2006. The longest time series could be established for PBDEs, partly based on archived material, while PCBs and DDTs covered a study period from 1994-2006. All organochlorines showed decreasing trends, most pronounced for DDT and HCH with an annual change of 8%. BDE-47 had a significantly increasing trend of 5% annually. It was the only BDE congener consistently above the detection limit, with annual median concentrations between 0.78 ng/g lw to 3.54 ng/g lw, i.e. about 10 times lower than values from East Greenland observed in a similar time trend study on ringed seal blubber [Rigét F, Vorkamp K, Dietz R, Rastogi SC. Temporal trend studies on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in ringed seals from East Greenland. J Environ Monit 2006; 8: 1000-5]. A clear East>West difference was also found for PCBs and DDTs, but not for chlordanes, toxaphene or HCHs. Sigma 10-PCB, Sigma DDT and Sigma Chlordanes had similar annual median concentrations, typically exceeding SigmaPBDE by two orders of magnitude. The concentrations of HCH and toxaphene were in an intermediate group, with highest annual median concentrations of 135 ng/g lw and 20 ng/g lw, respectively. For most compound groups, the circumpolar trend previously established under for example the Arctic Monitoring and Assessment Programme was confirmed, but apparently, more data are needed for chlordane-related compounds and toxaphene. Statistical analyses of the compound patterns in the ringed seal samples revealed significantly greater differences between seals from East and West than between different sampling years. Higher proportions of PCBs and DDTs and lower proportions of chlordanes and HCHs were found in seals from East Greenland than in those from West Greenland. Based on principal component analysis of individual congener and compounds, seals from East Greenland were found to contain higher proportions of the higher chlorinated CB congeners. Varying patterns between sampling locations may be caused by different exposure situations related to contaminant emissions and transport, but different feeding habits may also affect the contaminant composition.     

State of the art in the analysis of brominated flame retardants in biota and sediment: insights from the characterisation of two new certified reference materials

Environmental Science and Pollution Research - The Joint Research Centre (JRC) of the European Commission has recently released two new Certified Reference Materials (CRMs) for the analysis of...     

Fate of the fungicide dodemorph during anaerobic digestion of biological waste

The aim of this study was to examine the stability and distribution of the fungicide dodemorph during anaerobic digestion of biological waste, including a short subsequent aerobic treatment. Three reactor experiments were conducted. The influences of pH and dissolved organic carbon (DOC) were further studied in batch experiments. The reactor experiments showed no decrease in the concentration of dodemorph, indicating stability of the fungicide. In connection with the results of the batch experiments, a clear pH-dependency of the partitioning of dodemorph between solid and water phase could be shown. At pH values below the pK(a) value of 7.8, protonated dodemorph molecules predominate. However, a release into the water phase was only observed at pH values of 5 and below. It can be assumed that in the pH range between 5 and 7.8 dodemorph forms bonds with carboxyl groups of organic matter. Dodemorph was not completely extractable from the solid waste matrix due to strong bonds with the organic matter. Solubilising effects by water ingredients of the process water were not apparent.     

14C-Photosynthesis of Phytoplankton in an Oligotrophic Alpine Lake (Traunsee,Austria) and its Response to Turbidity Caused by Industrial Tailings

The influence of industrial tailings on the biological integrity of the phytoplankton was assessed from annual measurements of photosynthetic rates in the alpine lake Traunsee. The mean annual integral production of 21 mmol C m^-2 d^-1 corresponded to the oligotrophic nature of the lake. Effects of effluents were tested by comparing photosynthesis at a station close to the industrial outlet (EB) and at a reference site with a maximum depth of 190 m (VI). Between-site optical properties (vertical attenuation coefficient, euphotic depth) were statistically significant different. The euphotic zone at the impacted station was on average 2 m shallower than at the reference site, owing to turbidity emanating from the industrial plant. The adaptation to low light intensities by the algal community at this station was evident from a high maximum light utilisation coefficient (^* at low light saturation (E _K). Algae at the deep reference site were photosynthetically less efficient but adapted to high light intensities. Photosynthetic adaptation to different light climates in the euphotic zone without significant quantitative biomass alterations at the impacted site gave a clear signature of biological integrity of the phytoplankton in the oligotrophic Traunsee.