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The application of δ 18 O and δ D for understanding water pools and fluxes in a Typha marsh
Author(s) -
BIJOOR NEETA S.,
PATAKI DIANE E.,
ROCHA ADRIAN V.,
GOULDEN MICHAEL L.
Publication year - 2011
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02372.x
Subject(s) - typha , evapotranspiration , eddy covariance , marsh , hydrology (agriculture) , environmental science , water balance , transpiration , growing season , environmental chemistry , atmospheric sciences , chemistry , wetland , agronomy , ecology , ecosystem , photosynthesis , geology , biology , biochemistry , geotechnical engineering
The δ 18 O and δ D composition of water pools (leaf, root, standing water and soil water) and fluxes [transpiration ( T ), evaporation ( E )] were used to understand ecohydrological processes in a managed Typha latifolia L. freshwater marsh. We observed isotopic steady‐state T and deep rooting in Typha . The isotopic mass balance of marsh standing water showed that E accounted for 3% of the total water loss, T accounted for 17% and subsurface drainage ( D ) accounted for the majority (80%). There was a vertical gradient in water vapour content and isotopic composition within and above the canopy sufficient for constructing an isotopic mass balance of water vapour during some sampling periods. During these periods, the proportion of T in evapotranspiration ( T / ET ) was between 56 ± 17% and 96 ± 67%, and the estimated error was relatively high (>37%) because of non‐local, background sources in vapour. Independent estimates of T / ET using eddy covariance measurements yielded similar mean values during the Typha growing season. The various T / ET estimates agreed that T was the dominant source of marsh vapour loss in the growing season. The isotopic mass balance of water vapour yielded reasonable results, but the mass balance of standing water provided more definitive estimates of water losses.