Spatial and temporal patterns of soil water storage and vegetation water use in humid northern catchments

Josie Geris; Doerthe Tetzlaff; Jeffrey J McDonnell; Chris Soulsby

doi:10.1016/j.scitotenv.2017.03.275

Spatial and temporal patterns of soil water storage and vegetation water use in humid northern catchments

Sci Total Environ. 2017 Oct 1:595:486-493. doi: 10.1016/j.scitotenv.2017.03.275.

Authors

Josie Geris¹, Doerthe Tetzlaff², Jeffrey J McDonnell³, Chris Soulsby²

Affiliations

¹ Northern Rivers Institute, School of Geosciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom. Electronic address: j.geris@abdn.ac.uk.
² Northern Rivers Institute, School of Geosciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom.
³ Northern Rivers Institute, School of Geosciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom; Global Institute for Water Security, National Hydrology Research Centre, University of Saskatchewan, Saskatoon, Canada.

PMID: 28395263
DOI: 10.1016/j.scitotenv.2017.03.275

Abstract

Using stable isotope data from soil and vegetation xylem samples across a range of landscape positions, this study provides preliminary insights into spatial patterns and temporal dynamics of soil-plant water interactions in a humid, low-energy northern environment. Our analysis showed that evaporative fractionation affected the isotopic signatures in soil water at shallow depths but was less marked than previously observed in other environments. By comparing the temporal dynamics of stable isotopes in soil water mainly held at suctions around and below field capacity, we found that these waters are not clearly separated. The study inferred that vegetation water sources at all sites were relatively constant, and most likely to be in the upper profile close to the soil/atmosphere interface. The data analyses also suggested that both vegetation type and landscape position, including soil type, may have a strong influence on local water uptake patterns, although more work is needed to explicitly identify water sources and understand the effect of plant physiological processes on xylem isotopic water signatures.

Keywords: Isotopes; Soil water storage; Vegetation water use.