Speleothem record of mild and wet mid-Pleistocene climate in northeast Greenland.

The five interglacials before the Mid-Brunhes Event (MBE) [c.430 thousand years (ka) ago] are generally considered to be globally cooler than those post-MBE. Inhomogeneities exist regionally, however, which suggest that the Arctic was warmer than present during Marine Isotope Stage (MIS) 15a. Using the first speleothem record for the High Arctic, we investigate the climatic response of northeast Greenland between c.588 and c.549 ka ago. Our results indicate an enhanced warmth of at least +3.5°C relative to the present, leading to permafrost thaw and increased precipitation. We find that δ18O of precipitation was at least 3‰ higher than today and recognize two local cooling events (c.571 and c.594 ka ago) thought to be caused by freshwater forcing. Our results are important for improving understanding of the regional climatic response leading up to the MBE and specifically provide insights into the climatic response of a warmer Arctic.

Climate change and landscape development in post-closure safety assessment of solid radioactive waste disposal: Results of an initiative of the IAEA.

The International Atomic Energy Agency has coordinated an international project addressing climate change and landscape development in post-closure safety assessments of solid radioactive waste disposal. The work has been supported by results of parallel on-going research that has been published in a variety of reports and peer reviewed journal articles. The project is due to be described in detail in a forthcoming IAEA report. Noting the multi-disciplinary nature of post-closure safety assessments, here, an overview of the work is given to provide researchers in the broader fields of radioecology and radiological safety assessment with a review of the work that has been undertaken. It is hoped that such dissemination will support and promote integrated understanding and coherent treatment of climate change and landscape development within an overall assessment process. The key activities undertaken in the project were: identification of the key processes that drive environmental change (mainly those associated with climate and climate change), and description of how a relevant future may develop on a global scale; development of a methodology for characterising environmental change that is valid on a global scale, showing how modelled global changes in climate can be downscaled to provide information that may be needed for characterising environmental change in site-specific assessments, and illustrating different aspects of the methodology in a number of case studies that show the evolution of site characteristics and the implications for the dose assessment models. Overall, the study has shown that quantitative climate and landscape modelling has now developed to the stage that it can be used to define an envelope of climate and landscape change scenarios at specific sites and under specific greenhouse-gas emissions assumptions that is suitable for use in quantitative post-closure performance assessments. These scenarios are not predictions of the future, but are projections based on a well-established understanding of the important processes involved and their impacts on different types of landscape. Such projections support the understanding of, and selection of, plausible ranges of scenarios for use in post-closure safety assessments.

Assessment of fungal diversity using terminal restriction fragment (TRF) pattern analysis: comparison of 18S and ITS ribosomal regions.

Assessment of fungal diversity in environmental samples is currently a challenge. Several recently developed molecular methods offer new avenues for determining the presence and diversity of fungi in complex microbial communities. Terminal restriction fragment (TRF) pattern analysis was tested as a method for assessing the fungal molecular diversity of a terrestrial microbial community. Community DNA was isolated from sand samples taken from a pilot-scale petroleum-contaminated land treatment unit. PCR amplification was carried out using primers, one of which was fluorescently labeled, designed to hybridize to conserved sequences in the fungal ribosomal small subunit (18S) or the internal transcribed spacer ITS1-5.8S-ITS2 (ITS) ribosomal region. Amplicons were then digested separately with HpaII or HaeIII; fluorescently labeled TRFs were detected by capillary gel electrophoresis. ITS region TRF patterns were predicted and observed to generate a greater richness than 18S TRF patterns. Unique TRF patterns were also observed for each community examined. Finally, the ITS region showed a higher degree of specificity in matching observed TRF profiles to those generated from GenBank sequence data for species identification. These data suggest that ITS rDNA TRF pattern analysis has great potential as a rapid and specific method for fungal community analysis and species identification.