Estimating the exposure of small mammals at three sites within the Chernobyl exclusion zone--a test application of the ERICA Tool

An essential step in the development of any modelling tool is the validation of its predictions. This paper describes a study conducted within the Chernobyl exclusion zone to acquire data to conduct an independent test of the predictions of the ERICA Tool which is designed for use in assessments of radiological risk to the environment. Small mammals were repeatedly trapped at three woodland sites between early July and mid-August 2005. Thermoluminescent dosimeters mounted on collars were fitted to Apodemus flavicollis, Clethrionomys glareolus and Microtus spp. to provide measurements of external dose rate. A total of 85 TLDs were recovered. All animals from which TLDs were recovered were live-monitored to determine (90)Sr and (137)Cs whole-body activity concentrations. A limited number of animals were also analysed to determine (239,240)Pu activity concentrations. Measurements of whole-body activity concentrations and dose rates recorded by the TLDs were compared to predictions of the ERICA-Tool. The predicted (90)Sr and (137)Cs mean activity concentrations were within an order of magnitude of the observed data means. Whilst there was some variation between sites in the agreement between measurements and predictions this was consistent with what would be expected from the differences in soil types at the sites. Given the uncertainties of conducting a study such as this, the agreement observed between the TLD results and the predicted external dose rates gives confidence to the predictions of the ERICA Tool.     

The trophic role of glycolic acid in coastal seawater. I. Heterotrophic metabolism in seawater and bacterial cultures

Glycolic acid, a known algal excretory product, represents a potentially important energy source for heterotrophic bacteria in marine waters. Measurements of heterotrophic uptake and mineralization by the natural microbes in the plankton indicate quantitative use of glycolic acid comparable to other common microbial substrates. This activity shows vertical and horizontal variations that correlate in a general way with primary productivity. Glycolic acid appears to be present at higher concentrations than other low molecular weight substrates, and it also shows a lower rate of turnover. It is mineralized (respired) to a greater extent than other recorded substrates, an average of 70% of total uptake. Two-thirds of a total of 141 colonies of bacteria cultured from seawater on marine agar proved capable oftaking up and respiring glycolic acid. These same bacteria, however, were unable to utilize glycolic acid for growth when it was the sole carbon source. Glycolate may therefore occur at higher concentrations and show erratic fluctuations in natural waters because microbial use is not tied to glycolate production but to the presence of other substrates. The fact that so many bacteria are able to metabolize it indicates a possibly important trophic role as an energy source. It is suggested that glycolic acid may be a major source of energy for active transport of other substrates by marine bacteria.     

Manipulation of sex differences in parental care

Summary In a species with biparental care two parents cooperate to provide the appropriate amount of care for the young. Recent theoretical treatments consider the evolutionarily stable investment strategy. Under most conditions, the parental investment of the two partners should be negatively correlated, with the shortfall of one partner being partially compensated for by the other. Previous experimental manipulations of biparental care have involved removal of one partner, yet the response of a widowed bird may differ from that of a mated bird whose partner is doing less than its fair share of parental care. We present the first data involving subtle manipulations of sex differences in parental care where both partners continue to care for the young. This study involves pairs in a nestbox colony of european starlings (Sturnus vulgaris L.) with all brood sizes manipulated to five chicks. Pairs were randomly assigned to three groups: (i) male parental care reduced; (ii) female parental care reduce; and (iii) control pairs. Parental care was manipulated by attaching small weights to the base of a bird's tail feathers. Regardless of sex, nest visitation rate was reduced in the weighted birds with an incomplete compensatory increase by their unweighted partner. Additional parental duties were also considered, including shifts in prey type delivered to the nest, in both weighted birds and their partners. The shift in diet and the overall lower total visitation rate in experimental nests contributed to slower chick growth and lower chick weights than in control nests. The data accord with models suggesting that equality of invesment in biparental species is evolutionarily stable, but reveal new dimensions of parental response that need to be taken into account in theoretical treatments.     

Growth,production and energy transformations in the salt-marsh killifish Fundulus heteroclitus

Populations of Fundulus heteroclitus (L.) at the beginning of a growth season in a New England salt marsh consist of 3 yearly age classes, with the 1-year-old class contributing most of the biomass. Calculation of production rates revealed that the young fish were the most active part of the population and that females were more productive than males. The entire population spent equal amounts of energy in growth and in metabolism. Including the young of the year, we obtained total production of 160 kg dry weight/ha, a value among the highest obtained for natural fish populations. About 5 to 15% of the production is available to predators. Rates of food consumption by F. heteroclitus are high enough to turn over the population of prey relatively often. Popululations of F. heteroclitus are thus capable of exerting an important influence on the abundance and distribution of their prey.Contribution No. 3721 from the Woods Hole Oceanographic Institution.     

Molecular behavior assessment on initial stages of oil spill in terrestrial environments

Environmental Science and Pollution Research - The contamination of terrestrial environments by oil spills creates biological risks to humans and affects the ecosystem’s health. The studies...     

University research for sustainable development: definition and characteristics explored

University research is pivotal for sustainable development, but to succeed, new ways of conducting research are needed. Only recently has the field of “sustainability and higher education” (SHE) started to deal with the issue. In this paper we define “university research for sustainable development” comprehensively as “all research conducted within the institutional context of a university that contributes to sustainable development”, and propose a set of twenty two preliminary characteristics of this concept. We provide foundational information in particular for various university stakeholders, and those of higher education in general, considering the (re)orientation of research towards sustainable development and offer a beginning of dialogue on the subject, within SHE.