C-CASCADES

'Modelling lateral carbon transfers through the in-land water network at regional to global scales' by Dr. Ronny Lauerwald

Dr. Ronny Lauerwald's short biography:

Ronny Lauerwald is currently a Marie Skłodovska-Curie post-doctoral fellow at the University of Exeter. His research focusses on simulating carbon (C) fluxes through the inland water network. During his PhD at the University of Hamburg (Germany), he used statistical modelling techniques combined with GIS to explore functional relationships between catchment properties and C biogeochemistry of rivers in North America. He developed spatially explicit models to assess the non-conservative fluvial transport of dissolved organic C and the large scale spatial patterns in river alkalinity, pH and CO₂ oversaturation at the continental scale. Based on this experience, he contributed to the first global map of CO₂ evasion from rivers and lakes (Raymond et al., 2013, Nature). During his Post-DOC at the Université Libre de Bruxelles (ULB) he worked within the EU project Geocarbon. During that time, he developed a GIS based, statistical modelling framework to produce refined, high resolution estimates of river CO₂ evasion at the global scale. In addition, he contributed to various studies re-assessing water-atmosphere CO₂ exchange in estuaries and the coastal ocean as well as to the collaborative work of establishing a bottom up, data driven global C budget. As a Post-DOC in a collaborative project between ULB and the Institut Pierre-Simon Laplace in France, he moved to the field of Earth System Modelling and made the pioneering step of implementing fluvial C transport into ORCHIDEE, the land surface scheme of the IPSL Earth-System model.

Lecture's abstract - 'Modelling lateral carbon transfers through the in-land water network at regional to global scales':

The lateral export of carbon (C) from soil and vegetation into the inland water network is of the same order of magnitude as the ‘residual‘ land C sink. However, only a small proportion of this C is delivered to the coast, while substantial amounts are respired in-transit and evade to the atmosphere or are buried in sediments. The combination of statistical modelling and GIS has proved useful to constrain fluvial C exports and CO₂ evasion from inland waters at the regional to global scale. However, it remains a challenge to attribute these C fluxes to different sources and to make quantitative statements about the anthropogenic perturbation and effects of climate change. For this, physical based modelling strategies are promising, but Earth system models (ESM) have so far ignored these lateral C transfers. For the first time, lateral C transfers and C transformations in inland waters have been implemented into ORCHIDEE, the land surface scheme of the IPSL ESM. This lecture gives an overview of the recent developments in ORCHIDEE and discusses the sources of dissolved organic carbon and CO₂ to the inland water network using the example of the Amazon Basin. The importance of seasonal flooding for the inland water C cycle will be highlighted.

Recommended background publication on this presentation:

Lauerwald, R., Laruelle, G. G., Hartmann, J., Ciais, P., and Regnier, P. A. G. (2015): Spatial patterns in CO2 evasion from the global river network. Global Biogeochem.Cycles, 29 (5), 534-554. Doi:10.1002/2014GB004941.