Research Topics

The new global high resolution lithological map (GLiM) was finalized end of 2012 (Hartmann & Moosdorf, 2012) and applied to develop a robust global chemical weathering model, which can be used in ESMs (Hartmann et al., 2014; Goll et al. in press). Analysis of the effect of scale, by comparing results from calculations with high resolution versus resolutions used in ESMs was conducted with focus on C and P (together with Victor Brovkin RA A). The GLiM was also used to improve global permeability and porosity data for improved hydrological modelling. Those new data can help to improve the subterranean hydrology parts of ESMs. The products developed in this subproject have led to involvement of the group in the NSF EarthCube Initiative.

Outgassing of CO2 from rivers and streams has been for the first time calculated globally in a regionalized manner using GLORICH (Raymond et al., 2013); it was about 1.8 Gt C a-1, higher than anticipated. Outgassing from estuaries for each coastal typology was published (Laruelle et a., 2013), to mirror the Land-Ocean-Aquatic-Continuum (LOAC) water pathways.

A new global dataset (MARCATS) was published harmonizing the river basins, coastal typologies and marine margins within one data set and applied in point before (Laruelle et al., 2013). In addition a new web-based interactive map of land-ocean carbon fluxes, PCO2 content of waters was created with partners in Brussels within the EU-Geocarbon project. A new estimate of carbon fluxes between the various reservoirs in the land-ocean aquatic continuum and a review of biogeochemical matter modelling in estuaries were assembled (Regnier et al., 2013, Regnier et al., 2014). These works shows that a global high resolution budget of carbon fluxes in estuaries is still not possible to lack of data for representative systems (Laruelle et al., 2013, Regnier et al., 2013).

Carbon fluxes and silica in the Elbe-Estuary were quantified (Amann et al., 2012, 2014a, 2014b, Weiss et al., 2012). One often used empirical thermodynamic parameter dataset (Millero-parameters) to calculate PCO2 was found to bias the calculation in the low salinity zone. Analysis was improved by using the full major element composition of the water for hydrochemical modelling based on principal thermodynamic considerations (Amann et al., 2014). The resources of the laboratory are now used in joint efforts with cooperation partners to elucidate processes steering Enhanced Weathering and the role of tectonic arcs in the carbon cycle, which are hypothesized to be hot spot areas of land-ocean matter fluxes. Increased understanding of the role of highly reactive geogenic materials in hotspot areas will improve the parameterization of future weathering models focusing at glacial-interglacial timescales.

The developed chemical weathering model for inorganic CO2-consumption by weathering and P-release was coupled with four ESMs to study the change in fluxes since 1850 (Goll et al., in press). Work on alkalinity fluxes and DOC-degradation was published (Lauerwald, 2012, 2013).

The applicability of the geoengineering concept of artificially enhanced weathering to remove carbon dioxide from the atmosphere was reviewed (Hartmann et al., 2013) and its CO2 efficiency determined. Currently, kinetic parameters for fresh reactive material on soils in the coupled mineral-plant-system are assessed. An international consortium was founded by our group during a workshop in Hamburg (Consortium for Research on Enhanced Weathering CREW, reported in Nature News).