|From||"Roger Brugge" <email@example.com>|
|Date||Tue, 27 Nov 2012 09:21:54 +0000|
Forwarded from CLIMLIST... Post-doctoral fellow offer in biogeochemistry and hydrology (Modeling inland water greenhouse gas fluxes) The excellence laboratory L-IPSL of the Institut Pierre-Simon Laplace offers a post-doctoral position of 2 years to integrate into the IPSL Earth System Model some of the key previously neglected inland aquatic processes than form the so called “boundless carbon cycle”. The proposed post-doctoral position project is a reaction to the growing awareness that inland waters contribute significantly to global greenhouse gas (GHG) fluxes, and to the realization that their sensitivity to projected climate change and eco-hydrological disturbance is poorly constrained. Context: The conventional wisdom is that inland waters simply transport terrigenous organic carbon to the oceans. This view is perpetuated by current models of the global carbon cycle that largely ignore inland waters as represented in, for instance, the Intergovernmental Panel for Climate Change (IPCC) – Fourth Assessment Report (FAR), or the Integrated Global Observing Strategy report (GEO-Carbon). In the five years since the publication of IPCC’s FAR in 2007, it has become apparent that the global flux of GHGs from inland aquatic sources to the atmosphere is much larger than previously suspected (Battin et al., 2008; 2009; Butman and Raymond, 2011; Bastviken et al., 2011; Barros et al., 2011). Thus, recently published estimates indicate that inland waters degas from 0.8 Pg (1Pg= 109 metric tons) of carbon per year (excluding wetlands, Cole et al. 2007), up to 3.3 Pg C y-1 (including wetlands, Tranvik et al., 2009; Battin et al., 2008; 2009; Aufdenkampe et al., 2011; Butman and Raymond, 2011), the latter estimate of similar magnitude to the terrestrial carbon sink of 2.8 Pg C y-1 (Canadell et al. 2008). Only recently have regional scale carbon balances begun to consider these fluxes (e.g. Luyssaert et al., 2012), but large knowledge gaps remain concerning their magnitude and their ultimate significance for global carbon cycle models. Current estimates based on global surveys and ‘bottom up’ extrapolations from streams and rivers in the United States for example indicate that this GHG flux is significant relative to the total anthropogenic flux of carbon to the atmosphere, with emissions from the northern hemisphere temperate zone (25oN-50oN) rivers alone estimated to be c. 0.5 Pg annually (Butman and Raymond, 2011). Additionally, a recent survey of CH4 emissions from inland aquatic systems (lakes, reservoirs and rivers) indicated annual CO2-equivalent methane emissions of a similar magnitude (0.65 Pg of C as CO2 equivalent; Bastviken et al., 2011). These recent estimates necessitate a paradigm shift from the traditional depiction of streams, rivers and other inland freshwater bodies as inert conduits and reservoirs, to one in which the kinetics of climate-sensitive GHG production by aquatic biogeochemical transformation reactions, hydrologically driven soil gas flushing from riparian zones and the dynamics of gas transfer processes at water/air interfaces are incorporated into realistic ‘boundless carbon cycle’ models. Despite the potential importance of these GHG emissions, their inclusion, even under a simplified form, in current Earth System Models is still missing, although several research teams began to work in that direction. The sensitivity of lateral C fluxes in aquatic systems to global change and eco-hydrological disturbances is largely unknown, and their overall significance for Earth’s global carbon budget remains to be established as well. Much previous work on regional scale carbon balances has focused on terrestrial sinks and sources, but it is increasingly appreciated that flux measurement techniques that are applied widely to terrestrial systems (e.g. Eddy covariance methods) are inappropriate or require re-evaluation for aquatic systems. Description of work: The postdoctoral fellow will interact with researchers at LSCE and SISYPHE laboratories, part of L-IPSL, and incorporate a set of simplified parameterizations on the land surface scheme ORCHIDEE of the IPSL Earth System model the following processes : C emissions from soils to rivers headstreams for DIC and DOC, with a highly parametric inclusion of chemical alteration fluxes of C from atmospheric origin, CO2 evasion data from rivers and floodplains, C burial in lakes and freshwater sediments and CO2 emissions from estuaries ( the later using the global upscaling model developped by Pierre Regnier at University of Utrecht). The ORCHIDEE model enabled for carbon transport from soil to rivers and lakes will be tested and calibrated against a new pCO2 global database and river fluxes of DOC, DIC (COSCAT database of 150 catchments; <http://www.agu.org/pubs/crossref/2006/2005GB002540.shtml>). The model will be applied in the second year for characterising the presently unknown atmospheric feedbacks (positive and negative) between inland aquatic carbon evasion fluxes and drivers such as climate change and anthropogenic eco-hydrological disturbance. Supervision team:The researcher with a PhD in earth system science, will be hired by CNRS and will be hosted at LSCE in Saclay (France) while working in close collaboration with SISYPHE in Paris. The work will be in a project team led by Philippe Ciais, including also Laurent Bopp, Josette Garnier, Sebastiaan Luyssaert and Christophe Rabouille. Duration and salary:Thepost-doctoratewillberecruitedfor24months with a net monthly salary around 2000 euros, commensurate with experience. This includes social services and health insurance. Contact for applications:Applications should include a vita, a statement of research interests and the names of at least two references including e-mail addresses and telephone numbers. Applications should be submitted by e-mail to Philippe Ciais (firstname.lastname@example.org).
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