PARENT SESSION
Poster Session 14: GIS and Remote Sensing
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Predicting stable isotope ratios of ²H and ¹⁸O in plants across terrestrial surfaces (ISOSCAPES).

West, Jason^*,1, Bowen, Gabriel¹, Ehleringer, James¹, ¹ University of Utah, Salt Lake City, UT

ABSTRACT- A focus on the influences of human activities on the functioning of biospheric processes has driven extensive research in the last few decades and yielded much progress. One aspect attempts to model global scale processes in order to predict the consequences of various human activities. These models are inherently spatially-explicit and depend on both accurate input data, as well as accurate understandings of the processes being modeled. Stable isotope ratios of several elements have been used successfully as both recorders of ecological processes, and tracers of the cycling and movement of elements through the biosphere. As such they have the potential to yield useful information across many scales. We have an expanded effort to link ecological and physiological process models with geographic information systems in order to make and test spatially-explicit predictions of stable isotope ratios for components of the biosphere (ISOSCAPES). We are also interested applying our understanding of spatial variations in isotope abundances to improve paleoclimatic and forensic reconstructions. We present results of our spatial predictions of ²H and ¹⁸O for major plant components across the terrestrial surface of the Earth. Predictions for leaf water and stem cellulose were based on a mechanistic model of leaf water enrichment and biochemical fractionations associated with cellulose formation. The model was driven spatially with globally gridded climate normals obtained from the ISLSCP-II Project and interpolated maps of source water isotope ratios. In addition to leaf water and cellulose, we present spatial predictions for the isotopic ratios of other plant components (e.g., seed lipids). The maps revealed significant latitudinal and continental variation that was consistent with expectations and the relatively limited spatially-explicit available data. Finally, we discuss the implications of these variations and future avenues of spatial-ecology research.

Key words: spatial, isotope, water, global