Confronting the water potential information gap

Authors: NOVICK, K. - University Of Indiana; FICKLIN, D.L. - University Of Indiana; BALDOCCHI, D. - University Of California; DAVIS, K.J. - Pennsylvania State University; GHEZZEHEI, T. - University Of California; KONINGS, A.G. - Stanford University; MACBEAN, N. - University Of Indiana; RAOULT, N. - Laboratoire Des Sciences Du Climat Et De L'Environnement (LSCE); Scott, Russell - Russ; SHI, Y. - Pennsylvania State University; SULMAN, B.N. - Oak Ridge National Laboratory; WOOD, J.D. - University Of Missouri

Submitted to: Nature Geoscience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2022
Publication Date: 3/11/2022
Citation: Novick, K., Ficklin, D., Baldocchi, D., Davis, K., Ghezzehei, T., Konings, A., MacBean, N., Raoult, N., Scott, R.L., Shi, Y., Sulman, B., Wood, J. 2022. Confronting the water potential information gap. Nature Geoscience. 15(3):158-164. https://doi.org/10.1038/s41561-022-00909-2.
DOI: https://doi.org/10.1038/s41561-022-00909-2

Interpretive Summary: Water potential, a measure of how tightly the water is held in tension, directly controls the function of leaves, roots and microbes, and differences in water potential determines water flows throughout the soil to the plants and to the atmosphere. Notwithstanding its clear relevance for many ecosystem processes, soil water potential is rarely measured at a site, and plant water potential observations are usually discrete, sparse, and not yet aggregated into accessible databases. These gaps limit our conceptual understanding of biophysical responses to moisture stress and inject large uncertainty into hydrologic and land surface models. Here, we outline the conceptual and predictive gains that could be made with more continuous and discoverable observations of water potential in soils and plants. We discuss improvements to sensor technologies that facilitate in situ characterization of water potential, as well as strategies for building new networks that aggregate water potential data across sites. We end by highlighting novel opportunities for linking more representative site-level observations of water potential to remotely-sensed satellite measurements. Together, these considerations offer a roadmap for clearer links between ecological and hydrological processes and the water potential gradients that have the potential to substantially reduce conceptual and modeling uncertainties.

Technical Abstract: Water potential directly controls the function of leaves, roots and microbes, and water potential gradients drive water flows throughout the soil-plant-atmosphere continuum. Notwithstanding its clear relevance for many ecosystem processes, soil water potential is rarely measured in-situ, and plant water potential observations are usually discrete, sparse, and not yet aggregated into accessible databases. These gaps limit our conceptual understanding of biophysical responses to moisture stress and inject large uncertainty into hydrologic and land surface models. Here, we outline the conceptual and predictive gains that could be made with more continuous and discoverable observations of water potential in soils and plants. We discuss improvements to sensor technologies that facilitate in situ characterization of water potential, as well as strategies for building new networks that aggregate water potential data across sites. We end by highlighting novel opportunities for linking more representative site-level observations of water potential to remotely-sensed proxies. Together, these considerations offer a roadmap for clearer links between ecohydrological processes and the water potential gradients that have the potential to substantially reduce conceptual and modeling uncertainties.