BiWaClim

Contact
Ansgar Kahmen

Time plan
2008 - 2010

Context/Aim

The Marie Curie project "Evaluating the effect of species composition and biodiversity on ecosystem water fluxes in a changing climate - A stable oxygen isotope study (BiWaClim)" was addressing the ¹⁸O isotope signal in ecosystem water pools and fluxes in a changing climate, using experiments and observational studies.

Research addressing the effects of global change on ecosystem ecology has mainly focused on carbon cycling, while the consequences for ecosystem water pools and fluxes have received little attention. Given the important regulating role of the vegetation for ecosystem hydrology, it is hypothesized that global change will not only affect ecosystem water relations directly (e.g. by altered precipitation patterns) but also indirectly through changes in plant water demand or altered plant species composition. The BiWaClim project did address the effects of species composition or biodiversity for ecosystem water pools and fluxes in a changing climate.

Approach

This project put particular emphasis on the use of oxygen isotopes in ecosystem water pools and fluxes. The ratio of ¹⁸O/¹⁶O isotopes has been suggested to be an indispensable tool for the understanding of ecosystem hydrology that allows a much deeper insight into patterns and processes than conventional methods. Despite the high potential, however, uncertainties remain in the interpretation of ¹⁸O isotope signals that have prevented the general application of stable oxygen isotope ratios in ecological studies.

Publications

Kahmen A, Livesley SJ, Arndt SK (2009) High potential but low actual glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability. Plant and Soil 325:109–121

Kahmen A, Simonin K, Tu KP, Merchant A, Callister A, Siegwolf R, Dawson TE, Arndt SK (2008) Effects of environmental parameters, leaf physiological properties and leaf water relations on leaf water δ¹⁸O enrichment in different Eucalyptus species. Plant, Cell and Environment 31: 738-751

Kahmen A, Simonin S, Tu KP, Goldsmith GR, Dawson TE (2009) The influence of species and growing conditions on the ¹⁸O enrichment of leaf water and its impact on “effective path length”. New Phytologist i184: 619-630

Sachse D, Kahmen A, Gleixner G (2009) Significant seasonal variation in the hydrogen isotopic composition of leaf-wax lipids for two deciduous ecosystems (Fagus sylvatica and Acer pseudoplananus). Organic Geochemistry 40: 732-742.