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8 June 2014 - 13 June 2014
Dates: 8-13 June 2014
Location: Sacramento, California, USA
For further information: http://goldschmidt.info/2014/index
GEOTRACES Town Hall:
The first GEOTRACES intermediate data product is now freely available on-line. The nature of the data made available, the data policy, and the procedure to access the data will be described. GEOTRACES (www.geotraces.org) is an international study of the marine biogeochemical cycles of trace elements and their isotopes. 654 stations (50 cruises) have been sampled resulting in 800 data sets. A question and answer session will follow a presentation of selected results and new data visualization tools.
Lunch boxes will be provided to the first 50 student participants and USB sticks containing the eGEOTRACES Atlas will be offered to the first 80 participants.
17e: Trace Elements, Microbes, and Biogeochemical Cycles in the Ocean Environment
Co-convenors: Kathy Barbeau, Maite Maldonado, Benjamin Twining
The relationships between trace metals and biota in the oceans are interactive, wide-ranging and can be perceived at molecular to ecosystem scales, with multiple connections to and consequences for the biogeochemical cycling of carbon and nitrogen. Developments in this field are being led by advances in analytical chemistry, nanotechnology, molecular biology, and bioinformatics as well as the expansion of ‘omics’-related observations of in-situ microbial communities and the advent of expansive new high resolution geochemical data sets via the international GEOTRACES program (www.geotraces.org). This session invites contributions which highlight trace metal-biota interactions and trace metal biogeochemistry in the oceans from a variety of perspectives. Presentations that include observations from ocean transects, process studies, laboratory or field-based incubation experiments and integration into models are encouraged.
16g: Sources, sinks and stores: integrating isotope and geochemical proxies for past and present surface processes, from elementary reactions to global change
Co-convenors: Tim Conway, Penelope Lancaster, Damien Lemarchand, Sunil Singh, Sambuddha Misra
Interactions between water and rock control the chemistry of surface waters as well as the sedimentary and oceanic geochemical budget over a range of time scales, with global implications for pressing environmental and energy questions. Recent improvements in high resolution analytical tools, especially geochemical and isotopic techniques by multi-collector ICP-MS, have advanced our understanding of these critical processes in disciplines as diverse as the ultra-low concentration constituents of seawater, the provenance of sediments and the mechanisms of chemical and physical weathering. This session invites state-of-the-art contributions which address critical uncertainties in our ability to interpret the recent abundance of geochemical data in three key areas: 1) Production and transport of sediments, including new isotopic and geochemical proxies for weathering rates (non-traditional stable isotopes like Li, Be, B, Mg, Ca, Si, Fe, Mo, U- and Th-series, isotopologues etc.); 2) isotopic and elemental fluxes to, from and within the ocean, and their influence on the composition of marine sediments and seawater dissolved isotope budgets (modeling/datasets focusing on novel marine isotope systems e.g. Cu, Cd, Zn, Fe, Ni etc., especially studies from the GEOTRACES program); and 3) interpreting sedimentary records, particularly studies which link highly-sophisticated single-grain analyses of heavy minerals (zircon, rutile, apatite, feldspar) to provenance and transport of sediment from source to sink.
14e: Climate and Biogeochemistry of Cryosphere Environments
Co-convenors: Lori Ziolkowski, Amy Townsend, Ashley Dubnick, Anders Carlson, Sarah Aciego, Alexandre Anesio, Jill Mikucki
Growing observations indicate dramatic changes in the cryosphere. The cryosphere includes frozen environments derived from sources of freshwater (glacial and ice-sheet ice, snow, lake ice), salt water (sea ice, ice shelves, saline lakes) and soil (permafrost). In this session we focus on three important aspects of the cryosphere: • Ice sheets as agents that influence sea level, and regional to global climate on orbital, millennial, centennial and anthropogenic timescales. Their dynamics need to be understood in the context of past climate changes; we will present new research across geomorphology, glaciology, geochemistry and oceanography that link paleoclimate information with ice sheet extent, volume, subglacial environments and regional and global climate change. • The history and ultimate fate of carbon released from arctic and alpine environments with implications for climate feedbacks in a warming world. We will present new research at the intersection of atmospheric, oceanic and terrestrial chemistry including novel analytical techniques, modeling and field measurements that study the carbon cycling of arctic and alpine environments. • Microbial organisms that have survive long-term encasement in an ice matrix and, in some cases, adapted to metabolize and even thrive within the ice. Evidence for their ability to influence the formation and decay of icy interfaces and to play important roles in the cycling of carbon and other climate is increasing. The inhabitants of Earth’s cryosphere also provide model systems for considering the evolution of life during Snowball Earth and possible analogs for life on other icy planets and moons. This session will bring together biologists, biogeochemists, glaciologists and astrobiologists to debate the most recent advances in understanding the habitation of ice on Earth — past, present and possibly beyond.
17a: Natural and Anthropogenic Impacts on Ocean Chemistry (Nutrients, Oxygen and the Biological Pump)
Co-convenors: Cecile Guieu, Linn Hoffman, Martha Gledhill, Jay Cullen
The colloidal phase of estuarine and marine waters, the interface between truly soluble and particulate matter, remains one of the greatest enigma’s in the study of marine biogeochemistry. Methods for studying this phase are operational and for the most part differ among studies, so with few exceptions then there are no means for quantitatively comparing findings. The colloidal phase itself comprises organic and inorganic materials, and it seems clear that the relative distribution of these phases changes spatially and temporally, even in oceanic environments. Sources comprise terrestrial outflow, aerosols (either direct or indirect), and in-situ processes. Although in some cases colloid aggregation has been demonstrated to facilitate the removal of “dissolved” substances, it also appears able to buffer truly soluble essential metals for phytoplankton growth (e.g., Fe). The aim of this session is to bring together those working on all aspects of marine-related colloids to gain a better understanding of our current state of knowledge of the marine colloidal phase. We particularly encourage presentations on the sources and processes affecting colloidal abundance and composition, and their effects on marine biogeochemical cycles.
17g: Hydrothermal Vents: Controls and Influences – Nano-Scale to Global – On Earth and Beyond
Convenors: Emma A. A. Versteegh, Kathrin Streit, Max Coleman
Deep-sea hydrothermal vents are hot spots for geochemical interactions. They have complex tectonic and structural controls, and in turn influence physical and biological processes on a wide range of spatial scales. These systems have been increasingly intensively studied since their discovery 37 years ago, and much scientific progress was made in recent years. Technical developments continuously improve our ability to investigate these extreme environments. Geochemists with diverse scientific backgrounds have made major contributions to our understanding of hydrothermal vent systems. This session aims to bring together these researchers, working at any of the relevant spatial scales on all aspects of hydrothermal vent geochemistry. Potential topics might include but are not limited to, the role of vents in global geochemical cycles (e.g. C, S and Fe), tectonic and structural controls on hydrothermal circulation and water-rock interaction, rock, and fluid chemistry, and the spectrum of ecosystems they support. We also encourage contributions looking at the potential significance of hydrothermal vents in the origin of life and in astrobiology, for example, habitability and potential biosignatures on the moons of the Outer Planets.
19c: The Biogeochemical Cycling of the Nutrients N, P and Si: Terrestrial and Marine Insights for the Present, Past and Future
Co-convenors: Karen Casciotti, Troy Baisden, Gabriel Filippelli, Mak Saito
Nutrients (e.g., Nitrogen, Phosphorous and Silicon) underpin vital processes within Earth’s ecosystems. In modern-day systems, these nutrient cycles exhibit complex, non-linear dynamics. Paleo-studies of nutrient cycles also suffer from this complexity, combined with imperfect geochemical preservation of evidence. New developments in biogeochemistry are improving our ability to describe nutrient dynamics in contemporary systems, and when combined with models, may also improve our ability to interpret the past and predict future responses of nutrients to global change. We consider both biologically-mediated nutrient cycles as well as cycles with competing biotic and abiotic regulation of sources or sinks. This theme encourages insights describing how biogeochemical nutrient dynamics can be understood in the face of apparent complexity, and applied to global changes in the past or future.
19f: Biogeochemical Processes Influencing Mobilization, Transformations, and Bioavailability of Mercury
Co-convenors: Helen Hsu-Kim, Nathan Yee, Andrew Graham
Mercury is a global pollutant and a neurotoxin that presents significant risks for human health. Solutions to the mercury problem can be difficult, due to the complex array of processes that ultimately lead to food web accumulation of this element in the form of monomethylmercury. This session will focus on the biogeochemical processes that influence the geochemical speciation of mercury, transport in the environment, and bioaccumulation. Specific topics include photochemical transformations, redox-related processes, biochemical pathways involved in net methylmercury production, and the consequences of climate change on the global Hg cycle.