Poster Details
THE DUAL ARRHENIUS - MICHAELIS MENTEN MODEL TO PREDICT TEMPERATURE AND NUTRIENTS EFFECTS ON MICROBIAL LITTER DECOMPOSITION IN STREAMS
Among global change drivers, nutrient enrichment and temperature raises have received considerable attention, and their effects on ecosystems are relatively well understood. However, anticipating the functional consequences of their concomitant variations remains challenging. Here we measured microbial leaf litter decomposition in 12 streams that exhibit contrasting dissolved nutrient concentrations along a seasonal temperature gradient. We then used the Bayesian inference to assess the relevance of several alternative models to predict litter decomposition from temperature and nutrient availability. The most complete model included an Arrhenius term (temperature effect) and Michaelis-Menten relationships for nitrogen and phosphorus effects, and allowed a linear influence of temperature on both half-saturation constants. From this full model, we derived several nested models that were compared using the Akaike Information Criterion. The Dual Arrhenius - Michaelis-Menten model gave a satisfying fit to our data, with the estimated activation energy value being 0.42 eV (±0.27 sd), and half saturation constants estimates 0.050 (±0.01 sd) mg N/L and 0.044 (±0.003 sd) mg P/L. We discuss the relevance of these estimates based on the existing knowledge on leaf decomposition limitations by temperature and nutrients.
Jérémy Jabiol (Co-Presenter/Co-Author), LIEC, Université de Lorraine, CNRS, France, jeremy.jabiol@univ-lorraine.fr;
Baba Camara (Co-Presenter/Co-Author), LIEC, Univ. Lorraine, France, bcamara@univ-metz.fr;
Michaël Danger (Co-Presenter/Co-Author), LIEC, Univ. Lorraine, France, michael.danger@univ-lorraine.fr;
Franck Gilbert (Co-Presenter/Co-Author), EcoLab, CNRS, Toulouse, franck.gilbert@univ-tlse3.fr;
Alice Gossiaux (Co-Presenter/Co-Author), LIEC, Université de Lorraine, CNRS, France, alice.gossiaux@univ-lorraine.fr;
François Guérold (Co-Presenter/Co-Author), LIEC, Université de Lorraine, CNRS, France, francois.guerold@univ-lorraine.fr;
Antoine Lecerf (Co-Presenter/Co-Author), EcoLab, Université de Toulouse, CNRS, France, antoine.lecerf@univ-tlse3.fr;
Pascal Poupin (Co-Presenter/Co-Author), LIEC, Univ. Lorraine, France, pascal.poupin@univ-lorraine.fr;
Eric Chauvet (Primary Presenter/Author,Co-Presenter/Co-Author), EcoLab, Université de Toulouse, CNRS, France, eric.chauvet@univ-tlse3.fr;