January 1, 2015.
The Landscape Evolution Observatory (LEO) consists of 3 theoretically identical, artificial hill slopes, the East, West, and Center slopes, aiming to investigate the movement of water, carbon, and energy. These slopes were designed to be identical in that they were all built to be the same size, and filled with the same amount of the same ‘soil’, which is actually granular basalt with loamy sand properties, with some small clay particle fractions to enhance its ability to hold water and for chemical weathering. With such a complex soil mixture, however, the geochemical differences between slopes at a given point can actually be quite significant. As the rain falls through these landscapes it is interacting with the different geochemistry, which naturally changes what is dissolved in the water. Through analyzing chemical differences from water samples collected from the different slopes, we can begin to develop a unique background for each hill slope, showing the ways in which they differ. To test this, a series of water collection syringes were distributed throughout the three different slopes at comparable collection points, where the water had already fallen through the landscape, so to be able to effectively compare the chemistries of those points on the slopes. This is critical to the project, as by better understanding the unique chemical characteristics of the individual slopes before further experimentation begins, effects that are coming from the experimental changes can be more effectively isolated from systematic differences. This project specifically focused on the comparison of 7 different anions, F-, Cl-, NO2-, Br-, NO3-, SO42-, PO43- , found in rainfall samples on the West and Center slopes. Concentrations of anions in water samples were found using Ion Chromatography. This study has shown that in terms of anion concentration, at comparable collection points, the slopes are far from identical.
Biosphere 2 (B2)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).