B2 WALD

Laura Meredith co-created and -led an international research campaign with Christiane Werner (University of Freiburg) and Nemiah Ladd (University of Basel) in the Biosphere 2 Tropical Rainforest biome. The Water, Atmosphere, and Life Dynamics (WALD, meaning ‘forest’ in German) campaign was a 5-month (Sept 2019 – Jan 2020) controlled whole-ecosystem drought and recovery experiment involving >90 participants from 14 institutions and 5 countries, $5M in instrumentation, and >20 media interviews. Our first results were just published in Science (Werner, Meredith, and Ladd, et al., 2021) with an accompanying perspective (Eisenhauer and Weigelt, 2021).

The overarching goal of the experiment was to fully track the forest’s response to drought from molecules to the ecosystem. We accomplished this by measuring multiple ecosystem compartments (atmosphere, leaf, stem, root, soil) online with 133 online gas sampling locations sampled by clusters of gas analyzers for water (H2O) isotopes, carbon dioxide (CO2) isotopes, volatile organic compounds (VOCs), and other trace gases (20 online gas analyzers total) and 290 additional environmental sensors. Moreover, we used the glass and steel structure enclosing the rainforest biome to precisely control the rainfall regime, and also to deliver stable isotope labeling at unprecedented ecosystem scales including whole atmosphere 13C-CO2 pulse labeling to track the speed and fate of C allocation under drought and control conditions and deep water 2H-H2O labeling to trace the role of plant deep water access.