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1. Adaptations to polar environments: “omics” and integration
Cryobiology 61 (2010) 362–408
Contents lists available at ScienceDirect
Cryobiology journal homepage: www.elsevier.com/locate/ycryo
Abstracts of papers and posters presented at the 47th Annual Meeting of the Society for Cryobiology held in Bristol, UK July 17–20, 2010. Student awards, 2010: The Society for Cryobiology awarded the Peter L. Steponkus Crystal Award for the best student paper and also the Best Poster Award, each following competitive evaluation of those presentations that were submitted to the competition. The winning presentatioins are noted at the relevant abstracts. Keynote session 1 Polar biology and climate change – Cryobiology in the environmental debate 1. Adaptations to polar environments: ‘‘omics” and integration. Melody S. Clark *, Peter Convey, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK To the human eye, the ‘poles’ are quintessentially extreme, and therefore anything that lives there must, almost by definition, in some way be special. While this is clearly an over-generalisation, the polar regions both on land and in the sea include environments that lie at one end of various environmental gradients that are seen on Earth. The study of biological responses to polar environmental adaptations and associated stresses therefore has and continues to form a large part of the research effort in these regions. Within the organism, at physiological, biochemical and ‘omics’ levels of study, a wide range of tactics in response to different environmental challenges (particularly cold, desiccation, osmotic stress, extreme seasonality) have been identified, and are often referred to as ‘adaptations’ even though few rigorous studies have linked these features to true evolutionary selection. At higher levels of organisation (e.g. individual, population, community, species), generalisations can similarly be made about the possession of common life history features many of which are clearly not adaptations sensu stricto. It is increasingly clear that future advances in understanding of response to environmental stress, not only in polar organisms, require integration across levels of biological organisation, for instance in quantification of energy budgets and trade-offs using not only the ‘‘traditional” tools of biochemical and physiological measures, but also integrating the new ‘‘omics” technologies to produce a holistic understanding of features that permit extremely flexible use of different life history strategy elements. Conflict of interest: None declared. Source of funding: Natural Environment Research Council. doi:10.1016/j.cryobiol.2010.10.005
2. Glaciers and ice sheets as active components of the Earth’s biosphere. J.L. Wadham, University of Bristol, UK The wet-based regions of the Greenland and Antarctic Ice Sheets are now known to constitute viable habitats for microbial life. They contain microbial consortia which drive chemical weathering and export nutrients and dissolved organic carbon via runoff to the coastal ocean, designating ice sheets as potentially important components of global biogeochemical cycles. Climate warming in the Polar Regions is likely to accelerate melting on the Greenland Ice Sheet and may initiate surface melting for the first time around Antarctica and in the Greenland interior. This has several implications for microbial composition and function in these ice-bound ecosystems. First, changes hydrological conditions may alter microbial habitats due to changing rock:water ratios and contact times. This could fundamentally affect the coupling between ice sheet environments and neighbouring ecosystems, which are believed to be sustained by bioavailable organic carbon and nutrients exported in glacial runoff. Second, there may be feedbacks between ice sheet wastage and climate via the release of greenhouse gases such as methane from the basal regions of ice sheets. Here, anoxic
doi:10.1016/S0011-2240(10)00165-3
conditions promote methanogenesis provided an organic carbon source exists. Our recent data show elevated carbon dioxide (up to 44,000 ppmv) and methane (up to 2000 ppmv) concentrations, together with depleted oxygen (relative to the atmosphere) in air bubbles in basal ice from both the Antarctic and Greenland Ice Sheets and are consistent with in situ microbial respiration and methanogenesis, respectively. Rates of methane production (per methanogen cell) from long-term microcosm experiments (10–1000 fg CH4 cell 1) align with values quoted for major methanogenic wetlands such as lakes and tundra soils. Given the areal extent and duration of glaciation in Antarctica, the magnitude of the sub-Antarctic methane reserve could be significant compared to other major global carbon pools. These results indicate that microbially-mediated processes in glaciers and ice sheets may have important feedbacks to both neighbouring ecosystems and the atmosphere, and should be considered in Earth System Models. Conflict of interest: None declared. Source of funding: None declared.
doi:10.1016/j.cryobiol.2010.10.006
3. Glacier surface ecosystems: monitoring life at the tipping point. Liz Bagshaw, School of Geographical Sciences, Bristol University, UK Glacier surface ecosystems are amongst the least studied components of the Earth’s biosphere, yet they are known to harbour significant microbial populations, potentially contributing to global scale biogeochemical cycles of carbon and nutrients. Many of these perennially cold and remote ecosystems are believed to display heightened sensitivity to climate change, as small temperature perturbations near zero degrees have large impacts on water supply and hence biological processes. Glacier surface habitats, such as cryoconite holes and cryolakes, provide ecological niches where liquid water and nutrients are present in sufficient quantities for primary production to occur. The relative balance between autotrophic and heterotrophic activity in these systems may provide the key to understanding nutrient and carbon cycling processes in polar desert environments and hence relative contributions to both local and global biogeochemical cycles. Measuring such processes is however, challenging in the polar environment, where traditional monitoring techniques are hampered by extreme cold, limited quantities of liquid water, and limited accessibility.Recent developments in sensor technologies for marine studies have demonstrated the potential for deployment in the long term monitoring of glacier surface biogeochemical processes, particularly for capturing high resolution spatial and temporal changes in ecosystem form and function. The application of these technologies in the polar environment presents promising results for the monitoring of glacier surface ecosystems, and has revealed complex relationships between biogeochemical parameters and physical controls. The impacts of even small changes in climate could cause significant changes to these sensitive ecosystems. Conflict of interest: None declared. Source of funding: None declared. doi:10.1016/j.cryobiol.2010.10.007
Contents lists available at ScienceDirect
Cryobiology journal homepage: www.elsevier.com/locate/ycryo
Abstracts of papers and posters presented at the 47th Annual Meeting of the Society for Cryobiology held in Bristol, UK July 17–20, 2010. Student awards, 2010: The Society for Cryobiology awarded the Peter L. Steponkus Crystal Award for the best student paper and also the Best Poster Award, each following competitive evaluation of those presentations that were submitted to the competition. The winning presentatioins are noted at the relevant abstracts. Keynote session 1 Polar biology and climate change – Cryobiology in the environmental debate 1. Adaptations to polar environments: ‘‘omics” and integration. Melody S. Clark *, Peter Convey, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK To the human eye, the ‘poles’ are quintessentially extreme, and therefore anything that lives there must, almost by definition, in some way be special. While this is clearly an over-generalisation, the polar regions both on land and in the sea include environments that lie at one end of various environmental gradients that are seen on Earth. The study of biological responses to polar environmental adaptations and associated stresses therefore has and continues to form a large part of the research effort in these regions. Within the organism, at physiological, biochemical and ‘omics’ levels of study, a wide range of tactics in response to different environmental challenges (particularly cold, desiccation, osmotic stress, extreme seasonality) have been identified, and are often referred to as ‘adaptations’ even though few rigorous studies have linked these features to true evolutionary selection. At higher levels of organisation (e.g. individual, population, community, species), generalisations can similarly be made about the possession of common life history features many of which are clearly not adaptations sensu stricto. It is increasingly clear that future advances in understanding of response to environmental stress, not only in polar organisms, require integration across levels of biological organisation, for instance in quantification of energy budgets and trade-offs using not only the ‘‘traditional” tools of biochemical and physiological measures, but also integrating the new ‘‘omics” technologies to produce a holistic understanding of features that permit extremely flexible use of different life history strategy elements. Conflict of interest: None declared. Source of funding: Natural Environment Research Council. doi:10.1016/j.cryobiol.2010.10.005
2. Glaciers and ice sheets as active components of the Earth’s biosphere. J.L. Wadham, University of Bristol, UK The wet-based regions of the Greenland and Antarctic Ice Sheets are now known to constitute viable habitats for microbial life. They contain microbial consortia which drive chemical weathering and export nutrients and dissolved organic carbon via runoff to the coastal ocean, designating ice sheets as potentially important components of global biogeochemical cycles. Climate warming in the Polar Regions is likely to accelerate melting on the Greenland Ice Sheet and may initiate surface melting for the first time around Antarctica and in the Greenland interior. This has several implications for microbial composition and function in these ice-bound ecosystems. First, changes hydrological conditions may alter microbial habitats due to changing rock:water ratios and contact times. This could fundamentally affect the coupling between ice sheet environments and neighbouring ecosystems, which are believed to be sustained by bioavailable organic carbon and nutrients exported in glacial runoff. Second, there may be feedbacks between ice sheet wastage and climate via the release of greenhouse gases such as methane from the basal regions of ice sheets. Here, anoxic
doi:10.1016/S0011-2240(10)00165-3
conditions promote methanogenesis provided an organic carbon source exists. Our recent data show elevated carbon dioxide (up to 44,000 ppmv) and methane (up to 2000 ppmv) concentrations, together with depleted oxygen (relative to the atmosphere) in air bubbles in basal ice from both the Antarctic and Greenland Ice Sheets and are consistent with in situ microbial respiration and methanogenesis, respectively. Rates of methane production (per methanogen cell) from long-term microcosm experiments (10–1000 fg CH4 cell 1) align with values quoted for major methanogenic wetlands such as lakes and tundra soils. Given the areal extent and duration of glaciation in Antarctica, the magnitude of the sub-Antarctic methane reserve could be significant compared to other major global carbon pools. These results indicate that microbially-mediated processes in glaciers and ice sheets may have important feedbacks to both neighbouring ecosystems and the atmosphere, and should be considered in Earth System Models. Conflict of interest: None declared. Source of funding: None declared.
doi:10.1016/j.cryobiol.2010.10.006
3. Glacier surface ecosystems: monitoring life at the tipping point. Liz Bagshaw, School of Geographical Sciences, Bristol University, UK Glacier surface ecosystems are amongst the least studied components of the Earth’s biosphere, yet they are known to harbour significant microbial populations, potentially contributing to global scale biogeochemical cycles of carbon and nutrients. Many of these perennially cold and remote ecosystems are believed to display heightened sensitivity to climate change, as small temperature perturbations near zero degrees have large impacts on water supply and hence biological processes. Glacier surface habitats, such as cryoconite holes and cryolakes, provide ecological niches where liquid water and nutrients are present in sufficient quantities for primary production to occur. The relative balance between autotrophic and heterotrophic activity in these systems may provide the key to understanding nutrient and carbon cycling processes in polar desert environments and hence relative contributions to both local and global biogeochemical cycles. Measuring such processes is however, challenging in the polar environment, where traditional monitoring techniques are hampered by extreme cold, limited quantities of liquid water, and limited accessibility.Recent developments in sensor technologies for marine studies have demonstrated the potential for deployment in the long term monitoring of glacier surface biogeochemical processes, particularly for capturing high resolution spatial and temporal changes in ecosystem form and function. The application of these technologies in the polar environment presents promising results for the monitoring of glacier surface ecosystems, and has revealed complex relationships between biogeochemical parameters and physical controls. The impacts of even small changes in climate could cause significant changes to these sensitive ecosystems. Conflict of interest: None declared. Source of funding: None declared. doi:10.1016/j.cryobiol.2010.10.007