Variation in chronic radiation exposure does not drive life history divergence among Daphnia populations across the Chernobyl Exclusion Zone

Ionizing radiation is a mutagen with known negative impacts on individual fitness. However, much less is known about how these individual fitness effects translate into population‐level variation in natural environments that have experienced varying levels of radiation exposure. In this study, we sampled genotypes of the freshwater crustacean, Daphnia pulex, from the eight inhabited lakes across the Chernobyl Exclusion Zone (CEZ). Each lake has experienced very different levels of chronic radiation exposure since a nuclear power reactor exploded there over thirty years ago. The sampled Daphnia genotypes represent genetic snapshots of current populations and allowed us to examine fitness‐related traits under controlled laboratory conditions at UK background dose rates. We found that whilst there was variation in survival and schedules of reproduction among populations, there was no compelling evidence that this was driven by variation in exposure to radiation. Previous studies have shown that controlled exposure to radiation at dose rates included in the range measured in the current study reduce survival, or fecundity, or both. One limitation of this study is the lack of available sites at high dose rates, and future work could test life history variation in various organisms at other high radiation areas. Our results are nevertheless consistent with the idea that other ecological factors, for example competition, predation or parasitism, are likely to play a much bigger role in driving variation among populations than exposure to the high radiation dose rates found in the CEZ. These findings clearly demonstrate that it is important to examine the potential negative effects of radiation across wild populations that are subject to many and varied selection pressures as a result of complex ecological interactions

Genetic, epigenetic and microbiome characterisation of an earthworm species (Octolasion lacteum) along a radiation exposure gradient at Chernobyl

The effects of exposure to different levels of ionising radiation were assessed on the genetic, epigenetic and microbiome characteristics of the “hologenome” of earthworms collected at sites within the Chernobyl exclusion zone (CEZ). The earthworms Aporrectodea caliginosa (Savigny, 1826) and Octolasion lacteum (Örley, 1881) were the two species that were most frequently found at visited sites, however, only O. lacteum was present at sufficient number across different exposure levels to enable comparative hologenome analysis. The identification of morphotype O. lacteum as a probable single clade was established using a combination of mitochondrial (cytochrome oxidase I) and nuclear genome (Amplified Fragment Length Polymorphism (AFLP) using MspI loci). No clear site associated differences in population genetic structure was found between populations using the AFLP marker loci. Further, no relationship between ionising radiation exposure levels and the percentage of methylated loci or pattern of distribution of DNA methylation marks was found. Microbiome structure was clearly site dependent, with gut microbiome community structure and diversity being systematically associated with calculated site-specific earthworm dose rates. There was, however, also co-correlation between earthworm dose rates and other soil properties, notably soil pH; a property known to affect soil bacterial community structure. Such co-correlation means that it is not possible to attribute microbiome changes unequivocally to radionuclide exposure. A better understanding of the relationship between radionuclide exposure soil properties and their interactions on bacterial microbiome community response is, therefore, needed to establish whether these the observed microbiome changes are attributed directly to radiation exposure, other soil properties or to an interaction between multiple variables at sites within the CEZ

XIV Theriological School-Seminar: summary of the workshop (Chornobyl 2007)

XIV Theriological School-Seminar took place nearby the Chornobyl Exclusion Zone (24–28 September 2007) to return back attention of researchers-naturalists and environmentalists to the nature of the region. The main topics were: ‘Fauna monitoring and distant studies of mammals’, and ‘Problems of fauna research and protection in the Chornobyl zone’. Up to 65 participants from 40 organizations of Ukraine, Belarus and Russia gathered at the School-Seminar. Fifty two reports were presented during 4 days. Two round tables, a get-to-know visit to the Chornobyl Exclusion Zone, an information fair, and a contest of young researchers in Theriology took place there

THE EVALUATION OF EFFICIENCY OF THE FERROCYANIDES FOR THE REDUCTION OF *991*993*997Cs CONTENT IN THE CATTLE PRODUCTS

The dependence of the efficiency of the ferrocyanide preparations (for the reduction of the radiocesium accumulation in the animal's organism) on the different conditions of its use had been studied. The results have been obtained in the course of 5 experiments on the cattle and sheeps, using the foods, to be contaminated as a result of the Chernobul AES emergency (10 to 180 kBk/kg). It has been established, that under the conditions of the cattle-keeping farm, preparations Ferrocine-2, Bifezh and CINOM show practically the same efficiency. For the first time it has been shown that, the older the animals the lower is the efficiency of the ferrocyanides; the intensity of leading the radiocesium out at application of ferrocyanides is proportional to the initial content of radionuclides in the organism; the longer time the ferrocyanide is being used, the higher its efficiency; on the method of design of the efficiency its value depends. The recommendations on the most optimum use of the preparations have been given. The results of the work have been used in the performance of the complex program "Ferrocyanide". They are necessary in the agricultural practice and in the scientific investigations, and in the development of the recommendations on application of ferrocyanidesAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Goodman_etal_Chernobyl_nonrep

Data on non-reproducing Daphnia pulex sampled from the Chernobyl Exclusion Zone and tested under UK background radiation dose rates at the University of Stirling

Strontium-90 and caesium-137 activity concentrations in bats in the Chernobyl exclusion zone

Bats are a protected species and as such may bean object of protection in radiological assessments of the environment. However, there have previously been only few radioecological studies of species of bats. In this paper, results for [140 measurements of 90Sr and 137Cs in 10 species of bats collected within the Chernobyl zone are presented. There was some indication of a decreasing transfer of 90Sr with increasing deposition, although this was inconsistent across species and explained little of the observed variability. There was no difference between male and female bats in the transfer (expressed as the ratio of whole-body activity concentrations to those in soil) of either radionuclide. There was considerable variability in transfer across all species groups. At two sites where there were sufficient data, Eptesicus serotinus was found to have higher transfer than other species

Goodman_etal_Chernobyl1

Life history data for Daphnia pulex sampled in Chernobyl and assessed under natural UK background conditions in the laboratory

Data from: Variation in chronic radiation exposure does not drive life history divergence among Daphnia populations across the Chernobyl Exclusion Zone

Ionising radiation is a mutagen with known negative impacts on individual fitness. However, much less is known about how these individual fitness effects translate into population-level variation in natural environments that have experienced varying levels of radiation exposure. In this study, we sampled genotypes of the freshwater crustacean, Daphnia pulex, from the eight inhabited lakes across the Chernobyl Exclusion Zone (CEZ). Each lake has experienced very different levels of chronic radiation exposure since a nuclear power reactor exploded there over thirty years ago. The sampled Daphnia genotypes represent genetic snapshots of current populations and allowed us to examine fitness-related traits under controlled laboratory conditions at UK background dose rates. We found that whilst there was variation in survival and schedules of reproduction among populations, there was no compelling evidence that this was driven by variation in exposure to radiation. Previous studies have shown that controlled exposure to radiation at dose rates included in the range measured in the current study reduce survival, or fecundity, or both. One limitation of this study is the lack of available sites at high dose rates, and future work could test life history variation in various organisms at other high radiation areas. Our results are nevertheless consistent with the idea that other ecological factors, e.g., competition, predation or parasitism, are likely to play a much bigger role in driving variation among populations than exposure to the high radiation dose rates found in the CEZ. These findings clearly demonstrate that it is important to examine the potential negative effects of radiation across wild populations that are subject to many and varied selection pressures as a result of complex ecological interactions