25-30 August 2013 – Florence, Italy
Call for sessions closes in October 2012.
Abstract submission closes in April 2013.
End of online registration is July 2013.
Already approved sessions relevant to GEOTRACES:
*17a. The ins and outs of mud: chemical fluxes between sediments and seawater
* 17b. Constraining rates of ocean processes
*17d. Isotope geochemistry of the modern oceans
*17g. Metal-biota interactions in seawater
We kindly remind colleagues planning a GEOTRACES Special Session to contact the GEOTRACES International Project Office in advance.
Marine sediments are the ultimate sink for many constituents in seawater, but this flux is significantly moderated at the seafloor before burial. Solute exchange between marine sediments and the overlying water column is occurring throughout the ocean basins. Elemental mass fluxes operate in both directions, often with profound effects on the local or global seawater chemistry. Rates of exchange are sensitive to various internal and external forcing mechanisms that operate on seasonal to geological time scales. In the shelf seas the benthic boundary layer communicates with the surface ocean through upwelling and mixing, thus providing a feedback between primary productivity and benthic respiration. Seafloor exchange in the deep ocean can contribute significantly in terms of the element’s global mass balance. Microbial processes are important drivers for many of these exchange processes in shallow and deep-sea sediments.
Technical innovations have led to improved quantification of these fluxes in the modern ocean, while development of novel paleo-proxies provide new insight into changes in the nature and rate of benthic-pelagic exchange over longer time scales. This session invites contributions that examine the process regulating benthic exchange, as well as techniques to quantify these fluxes on a variety of time scales.
Important physical, chemical, and biological processes in the ocean occur over a wide range of timescales from seconds up to millennia. Geochemical tools allow assessment of the rates and timescales of these processes. For example radiocarbon, nuclear bomb test products and long-lived U-series isotopes have been used to look at oceanic overturning circulation rates. Radiogenic thorium has been used to quantify fluxes of particles (and carbon) through the water column and to the seafloor, and radium has been used examine the extent of lateral advection from the continents to the ocean interior. These and other traditional and novel approaches provide insight into ocean mixing and biogeochemical cycling processes central to the ocean’s interaction with the Earth system as a whole. In this session we welcome contributions that use geochemical approaches to examining the rates of oceanic processes both in the modern ocean and in the past.
Isotope systems, stable and radiogenic, provide tracers to explore a wide variety of oceanic processes from ocean circulation to biological processes to particle export. While the processes traced by isotopes are diverse, commonalities exist among all isotope systems, in that they share similar analytical techniques and are produced and/or fractionated by similar chemical processes. Here, we encourage contributions that explore novel isotopic systems, and those that use developed isotope proxies in new and interesting ways to explore marine processes. Both stable and radiogenic isotope contributions are welcome, including tracers of nutrient and micronutrient sources and sinks in the ocean (e.g. N, O, Cd, Fe, Zn), tracers of the internal cycling of nutrients, and tracers of inorganic processes such as circulation and scavenging (e.g. Nd, Th) in the modern ocean.
Recent advances in analytical chemistry and molecular biological techniques indicate that trace metal micronutrients play an important role in regulating the species composition and physiological rate processes of the marine microbial community. Fully understanding the marine carbon and nitrogen cycles is thus intimately tied to our efforts to determine the distribution, chemical speciation and resulting bioavailability of trace metals to the marine biota. New and fruitful collaborations between chemical oceanographers and microbial physiologists are being achieved through, for example, high spatial resolution data as obtained via the ongoing international GEOTRACES program (www.geotraces.org). We invite submissions to this session which highlight trace metal-biota interactions and the complex interlacing of geochemical, physiological and ecological maps which shape the tempo and mode of carbon and nitrogen transformations in the ocean.