Themes and Sessions

14a: Present-Day Ocean Chemistry and Biogeochemical Cycling of Elements and Metals
Convenors: Ed Boyle, Robert Anderson
Keynote: Mak Saito (Woods Hole Oceanographic)
Orals: Thu AM, Thu PM
Posters: Tue AM
This session will emphasize the marine biogeochemical cycles of trace elements and their isotopes (TEIs), focusing on sources, sinks and internal cycling of TEIs in the modern ocean. A small number of processes dominate the supply of TEIs to the ocean; e.g., dust, rivers, groundwater and exchange with sediments. Similarly, a small number of processes (e.g., biological uptake, chemical scavenging, ocean circulation) regulate their internal cycling and eventual removal. This session invites contributions that offer new insights into these processes. Certain TEIs are particularly diagnostic of specific processes (e.g., Al as a tracer of dust supply; Mn as a tracer of mobilization from reducing sediments; Nd isotopes as a tracer of sediment exchange; micronutrients as tracers of biological uptake and internal cycling). Contributors are invited to highlight findings from selected tracers that can be extrapolated broadly to a larger suite of TEIs. Pesentations of new models that predict the transport and fate of TEIs introduced by human activities are invited as well.
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14b: New Developments in Marine Geochemical and Isotopic Proxies
Convenors: Anton Eisenhauer, Ben Reynolds, Morten Andersen, Basak Kisakurek
Orals: Fri AM, Fri PM
Posters: Tue AM
This session will bring together scientists developing new and improving classical proxies for marine geochemistry and paleoceanography. Contributions are welcome which use trace element and isotope ratios as proxy in various marine archives like sediments, carbonates, corals, foraminifera and sclerosponges. Furthermore, we are highly interested in those contributions using biomarkers as proxy to reconstruct particular conditions of the past.
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14c: Past Ocean Circulation
Convenors: Jerry McManus, Tina van de Flierdt
Keynote: Gideon Henderson (University of Oxford)
Orals: Mon AM, Mon PM
Posters: Tue AM
The short history of modern oceanographic observations prohibits a full evaluation of how ocean circulation has operated and changed in the past. This limits our understanding of the ocean’s influence on Earth’s climate, and its potential role in past and future climate change. Trace-element and isotope geochemistry are powerful tools to constrain such changes. For this session we invite contributions addressing past ocean circulation patterns from millennial to million year time-scales, and from the recent past to deep time. We also encourage contributions that integrate proxy data and models to understand the dynamics of past ocean circulation.
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14d: Ocean-Lithosphere Exchange and Fluid-Rock Interaction
Convenor: Bernhard Peucker-Ehrenbrink
Keynote: Katherine Kelley (University of Rhode Island)
Orals: Mon AM
Posters: Tue AM
The interaction of low- and high-temperature fluids with the oceanic crust significantly modifies the chemical composition of seawater by adding or removing elements and by modifying their isotope composition. Hydrothermal alteration and microbial processes in the shallow oceanic crust also modify the chemical composition and mineralogy of the crust. This has important implications for the composition of the altered oceanic crust that returns into the Earth's mantle. We invite contributions from all related fields ranging from isotopic and elemental analyses, speciation-based studies, to mineralogical investigations including the effects that microbial alteration of oceanic crust has on chemical fluxes and isotope composition. Contributions focusing on the microbiology, genomics and bioenergetics are referred to session 16f, 17j, and 16b or 19i, respectively.
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07c: Records of Ocean Anoxia and their Impact on Life, Climate, and Ocean Chemistry
Convenors: Gordon Love, Hugh Jenkyns, Tanya Goldberg
Keynote: Derek Vance (University of Bristol)
Orals: Thu AM, Thu PM
Posters: Mon PM
The recognition of carbon and other elemental cycles as principal drivers of environmental evolution over geological timescales is based on detailed sedimentary records generated and interpreted by geologists, geochemists and computational modellers over decades of research. Not until relatively late in our planet’s history, around 700-600 million years ago, did oxygen reach and then exceed the critical threshold required to establish and support basic animal life. The long-term burial of organic matter and iron sulfide minerals in sedimentary rocks are key processes controlling the maintenance of high levels of oxygen in the atmosphere since the late Neoproterozoic. Episodes of widespread deposition of organic-rich sediments on shelves and basins whose bottom waters were at least periodically anoxic/euxinic have been recognized throughout the Phanerozoic Eon and termed Oceanic Anoxic Events (OAEs). We seek exciting research contributions documenting and analyzing biogeochemical records of environmental and biological change through any of the Phanerozoic OAEs. Such contributions may describe fundamental shifts in: ocean redox structure, global climate and sea-surface temperature, primary production rates and microbial marine community structure, atmospheric pO₂ and pCO₂ estimates, as well as sedimentary organic-carbon/metal sulfide burial and preservation.
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07f: Cenozoic Climate Change: Bridging Model- and Data-Based Approaches to Reconstructing Cenozoic Temperature and Ocean/atmosphere Chemistry
Convenors: Sasha Turchyn, Jim Zachos
Keynotes: Jeffrey Kiehl (National Center for Atmospheric Research (NCAR)) , Stefan Schouten (Royal Netherlands Institute for Sea Research )
Orals: Wed AM
Reconstruction of ocean chemistry and climate over the Cenozoic allows for an intimate study of paleoclimate over timescales from thousands to millions of years. Access to well-preserved ocean sediments spanning all ocean basins, coupled with detailed knowledge of other climate and tectonic variables, yields high-resolution analysis addressing climatic changes through both model- and data-based approaches. Furthermore, the last 65 million years have witnessed dramatic shifts in temperature, ice volume, and ocean chemistry, as well as more transient perturbations to the carbon cycle, thus offering a rich field for scientific inquiry. Resolving the timing, nature, and causes of these climatic changes will help us better understand and interpret paleoceanographic variability earlier in Earth history. In this session we seek contributions from scientists exploring all aspects of Cenozoic climate change. We are particularly interested in work using novel paleoceanographic techniques, model-based approaches, and new interpretations of existing data to quantify aspects of ocean chemistry and climate.
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13c: Expansion of Oceanic Oxygen Minimum Zones
Convenors: Lothar Stramma, Denis Gilbert
Keynote: Nicolas Gruber (ETH Zürich)
Orals: Wed AM
Posters: Thu AM
Over the past five to ten years, changes in dissolved oxygen content has become a focal point of oceanic research. In the open ocean the oxygen content appears to decrease in most (but not all) areas, especially in the oxygen minimum zones. At the same time, low oxygen areas also known as “dead zones” have spread in the coastal oceans during the last decades. The oxygen change is an increasingly important topic due to its large impacts on the ecosystem and sedimentary feedbacks. A better understanding of the processes involved in oxygen change, the expansion of oceanic oxygen minimum zones and the interaction with the dead zones on the shelf shall be derived by discussing the present status of observations and modelling approaches of ocean oxygen changes in the geological past, in the last decades as well as from model predictions for the future.
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