Global separation of plant transpiration from groundwater and streamflow

Jaivime Evaristo, Scott Jasechko, Jeffrey J. McDonnell

Research output: Contribution to journalLetter

141 Citations (Scopus)

Abstract

Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir-the soil. However, recent work in Oregon(1) and Mexico(2) has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (H-2/H-1 (delta H-2) and O-18/O-16 (delta O-18)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the delta H-2/delta O-18 slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80% of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation-transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.

Original languageEnglish
Pages (from-to)91-94
Number of pages4
JournalNature
Volume525
Issue number7567
Early online date2 Sep 2015
DOIs
Publication statusPublished - 3 Sep 2015

Keywords

  • WATER-USE STRATEGIES
  • STABLE-ISOTOPES
  • SUMMER PRECIPITATION
  • SALINE GROUNDWATER
  • UPTAKE PATTERNS
  • LAND-SURFACE
  • CHINA
  • TREES
  • SOIL
  • FOREST

Cite this

Evaristo, J., Jasechko, S., & McDonnell, J. J. (2015). Global separation of plant transpiration from groundwater and streamflow. Nature, 525(7567), 91-94. https://doi.org/10.1038/nature14983

Global separation of plant transpiration from groundwater and streamflow. / Evaristo, Jaivime; Jasechko, Scott; McDonnell, Jeffrey J.

In: Nature, Vol. 525, No. 7567, 03.09.2015, p. 91-94.

Research output: Contribution to journalLetter

Evaristo, J, Jasechko, S & McDonnell, JJ 2015, 'Global separation of plant transpiration from groundwater and streamflow' Nature, vol. 525, no. 7567, pp. 91-94. https://doi.org/10.1038/nature14983
Evaristo, Jaivime ; Jasechko, Scott ; McDonnell, Jeffrey J. / Global separation of plant transpiration from groundwater and streamflow. In: Nature. 2015 ; Vol. 525, No. 7567. pp. 91-94.
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abstract = "Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir-the soil. However, recent work in Oregon(1) and Mexico(2) has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (H-2/H-1 (delta H-2) and O-18/O-16 (delta O-18)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the delta H-2/delta O-18 slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80{\%} of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation-transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.",
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AU - Evaristo, Jaivime

AU - Jasechko, Scott

AU - McDonnell, Jeffrey J.

N1 - Acknowledgements J.E. thanks the Saskatchewan Innovation and Opportunity Scholarship, Global Institute for Water Security, and School of Environment and Sustainability (University of Saskatchewan) for financial support.

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N2 - Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir-the soil. However, recent work in Oregon(1) and Mexico(2) has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (H-2/H-1 (delta H-2) and O-18/O-16 (delta O-18)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the delta H-2/delta O-18 slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80% of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation-transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.

AB - Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir-the soil. However, recent work in Oregon(1) and Mexico(2) has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (H-2/H-1 (delta H-2) and O-18/O-16 (delta O-18)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the delta H-2/delta O-18 slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80% of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation-transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.

KW - WATER-USE STRATEGIES

KW - STABLE-ISOTOPES

KW - SUMMER PRECIPITATION

KW - SALINE GROUNDWATER

KW - UPTAKE PATTERNS

KW - LAND-SURFACE

KW - CHINA

KW - TREES

KW - SOIL

KW - FOREST

U2 - 10.1038/nature14983

DO - 10.1038/nature14983

M3 - Letter

VL - 525

SP - 91

EP - 94

JO - Nature

JF - Nature

SN - 0028-0836

IS - 7567

ER -