High levels of fluctuating asymmetry in populations of Apodemus flavicollis from the most contaminated areas in Chornobyl

Random deviations from the perfect symmetry of normally bilaterally symmetrical characters for an individual with a given genotype occur during individual development due to the influence of multiple environmental factors. Fluctuating asymmetry (FA) is often used as a measure of developmental instability, and can be estimated as the variance of the distribution of differences between the left and right sides. We addressed the question of whether levels of FA were elevated in radioactively contaminated populations living around Chornobyl compared to those in reference populations of the yellow-necked mouse (Apodemus flavicollis). In addition, we studied amounts of directional asymmetry (DA) when one side is larger than the other on average. There was a significant difference among populations, including reference populations, in the amount of both FA and DA. A higher level of FA was documented for the contaminated populations in close proximity to the failed Chornobyl reactor for both the asymmetry of size and shape. The FAs of size and shape were highest in populations from the most contaminated locations in the Chornobyl exclusion zone. Although the directional asymmetry of shape was also highest in the contaminated populations, it was not significantly different from those in most of the reference populations. Populations from less contaminated areas inside the Chornobyl exclusion zone did not express FA values different from those of the reference populations outside the affected area. FA of skulls of A. flavicollis may indicate the degree to which the level of radioactive contamination affects the development of animals at Chornobyl. However, the mechanisms leading to these effects are not clear and probably vary from population to population. There were significant correlations between the overall right to left differences for the Procrustes aligned shape configurations, centroid sizes, and intramuscular (137)Cs. Detectable effects of radiation on developmental stability probably start to occur between 0.132 and 0.297 microGy/h.     

Understanding and predicting ecological dynamics: are major surprises inevitable?

Ecological surprises, substantial and unanticipated changes in the abundance of one or more species that result from previously unsuspected processes, are a common outcome of both experiments and observations in community and population ecology. Here, we give examples of such surprises along with the results of a survey of well-established field ecologists, most of whom have encountered one or more surprises over the course of their careers. Truly surprising results are common enough to require their consideration in any reasonable effort to characterize nature and manage natural resources. We classify surprises as dynamic-, pattern-, or intervention-based, and we speculate on the common processes that cause ecological systems to so often surprise us. A long-standing and still growing concern in the ecological literature is how best to make predictions of future population and community dynamics. Although most work on this subject involves statistical aspects of data analysis and modeling, the frequency and nature of ecological surprises imply that uncertainty cannot be easily tamed through improved analytical procedures, and that prudent management of both exploited and conserved communities will require precautionary and adaptive management approaches.     

Recycling of an acrylate–glass fiber reinforced polyester composite

Journal of Material Cycles and Waste Management - Recycling possibilities were evaluated for a composite waste composed of glass fiber reinforced polyester bound to a layer of crosslinked...     

Leaf reddening in the seagrass Thalassia testudinum in relation to anthocyanins, seagrass physiology and morphology, and plant protection

Numerous seagrass species growing in high-light environments develop red coloration in otherwise green leaves, yet the ecophysiology of leaf reddening in seagrasses is poorly understood. To increase our understanding of the process of leaf reddening in Thalassia testudinum found in the lower Florida Keys (USA), we identified the molecules responsible for red coloration in leaves and compared physiological, morphological, and growth attributes of entirely red-leafed shoots to entirely green-leafed shoots. We determined that four anthocyanin molecules are responsible for red coloration in leaves. In addition, we found that red leaves had higher concentrations of photoprotective pigments (anthocyanins and UV-absorbing compounds), higher effective quantum yields (ΔF/F _m′) at midday, and were shorter, narrower, and weighed less than green leaves. No significant difference in growth rates was observed between red- and green-leafed shoots, but patches of red-leafed shoots had shorter canopy heights and smaller LAI compared to patches of green-leafed shoots. Our results demonstrate that leaf reddening in T. testudinum is caused by high concentrations of anthocyanins, is associated with physiological and morphological attributes, and acts as a sunscreen since red leaves were able to maintain high effective quantum yields at high light intensities.