RCN: PSInet - A Global Water Potential Network

Indiana University, Bloomington IN

Investigators

Abstract

The ability to prepare for life on a warming planet requires a predictive understanding of how increasing drought and heat stress will affect terrestrial plants and the many services they provide, including food and timber production, carbon sequestration and storage, and the maintenance of biodiverse ecosystems. The water potential of soils and plants – which can be imagined as the blood pressure of the natural world – directly controls the flow of water through ecosystems and is a key regulator of the risk of plant mortality during droughts and heat waves. However, observations of water potential (commonly abbreviated with the Greek letter ‘Psi’) are frequently scarce, inaccessible, and plagued by methodological challenges that hinder the synthetic research necessary to anticipate, and prepare for, climate change impacts in natural and managed ecosystems. PSInet – a new network of data and people - will confront this information gap by: [1] promoting consistent collection and interpretation of water potential data by a global community of scientists through shared protocols, best practices, and early career training, [2] creating an open, global database for plant and soil water potential time series, and [3] supporting the synthesis of the PSInet database by a diverse community of scientists and practitioners to address previously intractable questions concerning plant responses to drought and heat stress. Gradients in water potential are the energetic basis for the flux of water through plants, and water potential is a determinant of how much carbon plants remove from the atmosphere, how much water they use in the process, and the likelihood that plants survive droughts. However, while the study of plant water potential is theory rich, it is relatively data poor. Observations of water potential in soils and plants are relatively sparse, discontinuous, and unaggregated. Closing this information gap is fundamental for addressing unresolved theoretical controversies about plant response to drought and heat stress, and for making confident predictions about ecosystem function in a warming world. PSInet will rise to this challenge by building a global water potential database with multiple points of connection to related environmental observation networks, enabling cross-site synthesis necessary for inference at regional and global scales, and providing a much-needed platform for testing and refining modeling schemes. We will also craft community-driven protocols and best practices to support water potential measurement and interpretation, with a particular emphasis on emerging approaches for continuous water potential observations, which hold tremendous promise but are currently hampered by methodological difficulties. Finally, the project will create a PSInet ‘Community of Practice’ to encourage data submissions, elevate the end-use of the database, and broaden the intellectual, demographic, and geographic diversity of ecophysiological research. Together, PSInet will provide the data, collaborative platforms, and training necessary to confront previously intractable questions about plant responses to drought and heat stress. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.