Our two weeks at Biosphere 2 in Arizona have now come to an end. Our capillary fringe experiment in mini LEO unfortunately had to be delayed, but Luke is planning to have it back up and running to continue the experiment next week. We’re keen to see how it goes from afar and pitch in for a group analysis and discussion of the results soon.
On the other hand, our plans for sampling in the rainforest came off without a hitch! Jaivime led two days of leaf sampling from the different tree species in the rainforest, as well as taking soil samples at different depths through the soil profile. These will be processed in the lab to obtain the isotopic signatures of the tree xylem water and of the soil water (on a side note: we will be extracting the soil water from the samples by cryogenic extraction, high-pressure squeezing and liquid-vapour equilibration, while lab testing – led by Dyan and Bruce – explores the relative effectiveness of each method for isotope analysis).
Back to the rainforest, and after Jaivime’s sampling it was all hands on deck to measure and sample the spatial distribution of rainfall in the biome during a scheduled rain event. We alternated between the rainforest surface to sample the rainfall, and the basement deep below the rainforest’s three meter soil profile to take subsurface flow samples. (So, yes… our newest study site is a basement beneath a rainforest in the middle of the Arizonan desert!) These water samples are now with us back in Saskatoon, where they will be analysed on the laser spec. This will form a benchmark for understanding the dynamics of where the rainforest biome’s trees access their water, in order to determine if and how they adapt when they undergo drought conditions (which will commence in the biome in the coming weeks).
All in all, we’ve had a great time down in Arizona! Many thanks go to Peter Troch, Luke Pangle, Joost van Haren, Guo-Yue Niu and everyone else at Biosphere 2 we worked with. We’re excited to have started some research collaborations with the team.