1. The Earth Institute's Lamont-Doherty Earth Observatory Earth Science Colloquium presents "How Would We Act If We Took Climate Change Seriously?" with Robert H. Socolow, Professor, Co-Director, The Carbon Mitigation Initiative, Princeton University.

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  2. Featuring: Henry Dick

    Woods Hole Oceanographic Institution

    Friday, February 18th, 2011
    Monell Auditorium

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  3. By Robin E. Bell


    When standing on the surface of the East Antarctic ice sheet where the average temperature is -50°C, it is difficult to imagine water moves through a subglacial hydrologic network 3000 meters beneath the camp. While scientists have long thought that there should be water beneath thick ice sheets it has only been over the last 15 years that we have learned that water can collect in lake the size of Lake Ontario, can move between lakes on the order of months and may modulate the speed of ice flowing in the large ice streams and outlet glaciers. During the International Polar Year a seven nation aerogeophysical team surveyed a region the size of California in the high interior of East Antarctica. The radar data reveals a previously unrecognized process of freeze-on that results in significant mass redistribution at the bottom of the ice. While surface accumulation of snow is considered the primary mechanism for ice sheet growth, beneath Dome A 24% of the base by area is frozen-on ice. In some places up to half the ice thickness has been added from below. These ice packages result from conductive cooling of water ponded along ridges of the Gamburtsev Subglacial Mountains and super-cooling of water forced up steep valley walls. Persistent freeze-on thickens the ice column, alters the basal ice temperature and fabric and upwarps the overlying ice sheet, including the oldest atmospheric climate archive, and drives flow behavior not captured in present models.

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  4. By Dr. John Joseph Cullen, rofessor of Oceanography in the Department of Oceanography at Dalhousie University

    Abstract: Optical observations from sensors on satellites, moorings and autonomous underwater vehicles have emerged as some of the most useful sources of information on the variability of ecological processes in the upper ocean. In turn, models of optically driven biological processes — both estimates of primary production from ocean color and simulations of phytoplankton for biogeochemical ocean general circulation models — have become essential tools for describing the ecology and biogeochemistry of the sea. The roots of phytoplankton models run deep, and analyses have almost always relied on the quantification of chlorophyll a, an imprecise but easily measured proxy for the biomass of phytoplankton and its capacity to absorb light for photosynthesis. Following suggestions that have been made repeatedly for well over a decade but not yet implemented in a comprehensive framework, I describe a modeling system that simulates the dynamics of optical properties directly, that is, by replacing the concentration of chlorophyll with the more directly relevant absorption coefficient for photosynthetic pigments. Photosynthesis is estimated by constraining photosynthetic quantum yield vs. absorbed radiation as a function of temperature, nutrient status and acclimation to light as expressed in the chemical composition and optical properties of photosynthetic cells, all of which are included in the model framework. The resulting direct simulation of the dynamics of optical properties could have distinct advantages, especially for the application of data assimilation procedures that would use optical measurements to drive both hindcast and forecast models. Further, the new formulations are designed to implement developing knowledge of the mechanistic links between the optical properties of microbes and their physiology and ecology, guiding new research in the process.

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  5. By Katrina Jane Edwards,
    Professor of Biological Sciences, Earth Sciences and Environmental Studies
    University of Southern California

    Abstract: Over the past two decades, there has been an increasing awareness within the geological, microbiological, and oceanographic communities of the potentially vast microbial biosphere that is harbored beneath the surface of the Earth. With this awareness has come a mounting effort to study this potential biome – to better quantify biomass abundance, activity, and biogeochemical activity. In the Earth system, the largest deep subsurface biome is also the least accessible – the deep ocean subsurface biosphere. The oceanic deep biosphere also has greatest potential for influencing global scale biogeochemical processes –the carbon and energy cycles for example, and other elemental cycles. To address these topics and mount interdisciplinary efforts to study the deep subsurface marine biosphere, we have recently formed a center in support integrative, collaborative investigations. The national science foundation Center for Dark Biosphere Investigations (C-DEBI), has been initiated for the explicit purpose of resolving the extent, function, dynamics and implications of the subseafloor biosphere. This talk will discuss C-DEBI science, with focus on some of the opportunities and challenges in the study of deep life in the ocean, and the role that C-DEBI will play in meeting them.

    # vimeo.com/22667268 Uploaded 34 Plays / / 0 Comments Watch in Couch Mode

Earth Science Colloquium Series

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The Earth Science Colloquium Series is sponsored by the Lamont-Doherty Earth Observatory and the Columbia University Department of Earth and Environmental Sciences (DEES). This series provides a lively forum for discussing a wide variety of topics within

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The Earth Science Colloquium Series is sponsored by the Lamont-Doherty Earth Observatory and the Columbia University Department of Earth and Environmental Sciences (DEES). This series provides a lively forum for discussing a wide variety of topics within the earth sciences and related fields.

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