Seasonal patterns of ascorbate in the needles of Scots Pine (Pinus sylvestris L.) trees: correlation analyses with atmospheric O3 and NO2 gas mixing ratios and meteorological parameters

In the present field study the role of ascorbate in scavenging the harmful atmospheric trace gases O3 and NO2 was examined. For this purpose ascorbate contents were determined in needles of adult Scots pine trees (Pinus sylvestris L.) during three consecutive years. Ascorbate contents were correlated with ambient tropospheric O3 and NO2 concentrations and with meteorological parameters. The results showed a strong correlation of atmospheric O3 but not of atmospheric NO2 concentrations with the apoplastic content of ascorbate during the seasonal course. Ascorbate contents in needle extracts did not correlate with ambient trace gas concentrations. In the apoplastic space, but not in needle extracts ascorbate contents correlate highly significantly with global radiation. From these results it is assumed that apoplastic ascorbate in Scots pine needles is adapted to the actual atmospheric O3 concentration to mediate immediate detoxification of O3, while the atmospheric O3 concentration itself is largely dependent on light intensity.     

SETAC GLB and SETAC Europe SAC: a liaison promoting the next generation of ecotoxicologists and environmental chemists

This commentary is an introduction for students to the Society of Environmental Toxicology and Chemistry (SETAC) and its Student Advisory Council (SAC). As young academics face challenges while trying to develop their careers, SETAC and the SAC help facilitate student involvement in the various communities within the society that can help to develop the students’ careers within the environmental sciences [e.g. the German Language Branch (GLB)]. This piece would also like to emphasize and pay homage to the continual cooperation between the SAC and the ESEU, which provides a scientific platform to communicate internationally and beyond the borders of SETAC, as well as offer heartfelt congratulations from the SAC to the GLB for their “20 Years SETAC GLB” and deep gratitude for their strong advocacy and support of the SAC.     

Environmental signals: synthetic humic substances act as xeno-estrogen and affect the thyroid system of Xenopus laevis

According to outdated paradigms humic substances (HS) are considered to be refractory or inert that do not directly interact with aquatic organisms. However, they are taken up and induce biotransformation activities and may act as hormone-like substances. In the present study, we tested whether HS can interfere with endocrine regulation in the amphibian Xenopus laevis. In order to exclude contamination with phyto-hormones, which may occur in environmental isolates, the artificial HS1500 was applied. The in vivo results showed that HS1500 causes significant estrogenic effects on X. laevis during its larval development and results of semi-quantitative RT-PCR revealed a marked increase of the estrogenic biomarker estrogen receptor mRNA (ER-mRNA). Furthermore, preliminary RT-PCR results showed that the thyroid-stimulating hormone (TSHbeta-mRNA) is enhanced after exposure to HS1500, indicating a weak adverse effect on T3/T4 availability. Hence, HS may have estrogenic and anti-thyroidal effects on aquatic animals, and therefore may influence the structure of aquatic communities and they may be considered environmental signaling chemicals.     

Heterozygosity,growth, and survival of the hard clam,Mercenaria mercenaria,in seagrass vs sandflat habitats

Populations of the hard clam,Mercenaria mercenaria L., sampled from dissimilar, adjacent habitats (October and November 1987), were used to assess environmental effects on associations among multi-locus heterozygosity, growth, and survival. Individuals were collected from three widely separated localities along the east coast of North America with each consisting of a seagrass bed and an adjacent, unvegetated sandflat. Demographic differences between adjacent populations were attributed to habitat type. Samples from intertidal sandflats at two of the localities were dominated by younger individuals than those from seagrass beds. Differential growth between adjacent populations was detected at only one locality wherein seagrass individuals grew faster than those from the sandflat. Allelic frequencies revealed adjacent populations that were genetically homogeneous. Nearly all of the genetic variance (98%) was within populations, yet a small (1.7%), but significant, portion occurred between localities. Observed and expected heterozygosities revealed a deficiency of heterozygotes in all six samples. Inbreeding and small-scale population subdivision were discounted as causative factors because deficiencies were heterogeneous across loci. Multi-locus heterozygosity was not correlated with growth rate in samples from any locality. Using a consensus test, multilocus heterozygosity was positively associated with ageclass in sandflat, but not seagrass, samples. We suggest that heterozygosity-fitness trait associations in marine bivalves are more likely to occur in populations inhabiting more stressful, fluctuating environments     

Electrophoretic identification and genetic analysis of bivalve larvae

Taxonomic identification and genetic analysis of larval marine invertebrates have been vexing problems. We describe a polyacrylamide mini-gel electrophoresis technique for resolving proteins from individual larval bivalves (shell length 250 to 350 m) and apply this technique to three species of laboratory-cultured larval oysters [Ostrea edulis L., 1758, Crassostrea gigas (Thunberg, 1793) and c. virginica (Gmelin, 1791)] reared during summer 1989. Electrophoretic patterns of proteins clearly discriminate among the three species and allow genetic analysis of a polymorphic allozyme locus (Pgi) in field-collected larvae and juveniles of C. virginica. This technique provides an economical tool for largescale taxonomic, ecologic, and genetic studies of meroplanktonic stages of various species.     

Climate change and human health—what influences the adoption of adaptation programming in the United States public health system?

With growing evidence on how climate change impacts human health, public health agencies should develop adaptation programs focused on the impacts predicted to affect their jurisdictions. However, recent research indicates that public health agencies in the United States have done little to prepare the public for predicted climate change impacts, largely due in response to a lack of resources and priority. This study surveyed Environmental Health (EH) Directors across the United States to determine the extent to which individual level attitudes and beliefs influence the adoption of climate change adaptation programming in a department. The results indicate that an EH Director’s perception of the health risk posed by climate change explained 27% of the variance in the number of climate change impacts being addressed. Furthermore, the study found that environmental attitude and political views made strong, unique contributions in explaining the variance in risk perception. The results provide evidence that individual-level attitudes and beliefs, as well as organizational-level barriers influence the adoption of climate change adaptation programs in public health agencies. As a result, increasing EH Directors’ perception of risk by highlighting the likelihood and severity of localized impacts may increase the adoption of adaptation programming despite existing organizational barriers (e.g., lack of resources). Given the fact that risk perception has been shown to influence behavior across cultures, these findings are also useful for understanding the influence of individual decision makers on public health programming around the world.