Toward a common methodological framework for the sampling, extraction, and isotopic analysis of water in the Critical Zone to study vegetation water use

Wiley Interdisciplinary Reviews Water, Journal Year: 2024, Volume and Issue: 11(4)

Published: March 5, 2024

Abstract The analysis of the stable isotopic composition hydrogen and oxygen in water samples from soils plants can help to identify sources vegetation uptake. This approach requires that heterogeneous nature plant soil matrices is carefully accounted for during experimental design, sample collection, extraction analyses. comparability shortcomings different methods extracting analyzing have been discussed specialized literature. Yet, despite insightful comparisons benchmarking methodologies laboratories worldwide, community still lacks a roadmap guide extraction, analyses, many practical issues potential users remain unresolved: example, which (soil or plant) pool(s) does extracted represent? These constitute hurdle implementation by newcomers. Here, we summarize discussions led framework COST Action WATSON (“WATer isotopeS critical zONe: groundwater recharge transpiration”—CA19120). We provide guidelines (1) sampling material analysis, (2) laboratory situ (3) measurements composition. highlight importance considering process chain as whole, design minimize biased estimates relative contribution conclude acknowledging some limitations this methodology advice on collection key environmental parameters prior article categorized under: Science Water > Hydrological Processes Environmental Change Extremes

Language: Английский

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On the Spatio-Temporal Under-Representation of Isotopic Data in Ecohydrological Studies

Frontiers in Water, Journal Year: 2021, Volume and Issue: 3

Published: March 11, 2021

OPINION article Front. Water, 11 March 2021Sec. Water and Critical Zone https://doi.org/10.3389/frwa.2021.643013

Language: Английский

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Phloem water isotopically different to xylem water: Potential causes and implications for ecohydrological tracing

Ecohydrology, Journal Year: 2022, Volume and Issue: 15(3)

Published: March 16, 2022

Abstract The stable isotopes of hydrogen and oxygen in xylem water are often used to investigate tree sources. But this traditional approach does not acknowledge the contribution stored phloem transpiration how may affect source interpretations. Additionally, there is a prevailing assumption that no isotope fractionation during transport. Here, we systematically sampled at daily subdaily resolutions large lysimeter planted with Salix viminalis . Stem diurnal change storage rates were also measured. Our results show significantly less enriched heavy than water. At resolution, observed larger isotopic difference between refilling under periods deficit. These findings contrast expectation heavy‐isotope due downward transport leaf signatures. Because previous evidence aquaporin mediated higher osmotic permeability lighter isotopologues across aquaporins, propose radial xylem–phloem boundary drive relative depletion their enrichment xylem.

Language: Английский

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A comparative study of plant water extraction methods for isotopic analyses: Scholander-type pressure chamber vs. cryogenic vacuum distillation

Hydrology and earth system sciences, Journal Year: 2022, Volume and Issue: 26(13), P. 3673 - 3689

Published: July 14, 2022

Abstract. Recent tracer-based studies using stable isotopes of hydrogen and oxygen showed that different methods for extracting water from plant tissues can return isotopic compositions due to the presence organic compounds because they extract domains. One most used is cryogenic vacuum distillation (CVD), which tends total water. Conversely, Scholander-type pressure chamber (SPC), commonly by tree physiologists measure potential in determine stress, expected only more mobile (i.e., xylem inter-cellular water). However, few reported application SPC analyses, therefore, inter-method comparisons between CVD are great value. In this work, we analyzed variability composition extracted CVD, also considering signature various leaves, twig without bark, with close trunk tree, wood core) species alder, apple, chestnut, beech). The extraction simple, be carried out field, it does not require specific laboratory work as case CVD. main limitation very small volume lignified twigs under stress conditions compared Our results indicated were significantly different. difference obtained two was smaller beech samples chestnut samples. enriched δ2H δ18O, respectively, than We conclude an alternative mostly extracts water, whereas retrieve all stored sampled tissue both living dead cells. aiming quantify relative contribution soil sources transpiration should rely on (which theoretically SPC) (sampled CVD), contains a fraction could longer time.

Language: Английский

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Flushing or mixing? Stable water isotopes reveal differences in arctic forest and peatland soil water seasonality

Hydrological Processes, Journal Year: 2023, Volume and Issue: 37(1)

Published: Jan. 1, 2023

Abstract Understanding the relative importance of different water sources that replenish soil storage is necessary to assess vulnerability sub‐arctic areas changes in climate and altered rain snow conditions, reflected timing magnitude infiltration. We examine spatiotemporal variability seasonal origin at soil‐vegetation interface Pallas catchment, located northern Finland. The field study was conducted from May 2019 June 2020 over two snowmelt seasons one summer growing season. sampled cores up a 1‐m depth stem dominant tree species four sites forests forested peatlands for stable isotopes. Seasonal rainfall variation late events were well identifiable well‐drained soils areas, while this input signal heavily attenuated wetter, peatland areas. Spatiotemporal forest similar, whereas controlled by extent hydrologic connectivity adjoining pools. A mixture both winter precipitation present during entire period, mineral showed an ephemeral response got nearly fully flushed twice hydrological year. Meltwater after early spring but became displaced isotopically enriched summer. evolution pools not dynamics offset between isotopic signals less pronounced peatlands. This data set uncovered high depth‐resolution, quantifying replenishing sustaining conditions.

Language: Английский

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Controls on leaf water hydrogen and oxygen isotopes: a local investigation across seasons and altitude

Hydrology and earth system sciences, Journal Year: 2023, Volume and Issue: 27(2), P. 599 - 612

Published: Jan. 30, 2023

Abstract. The stable oxygen (δ18Oleaf) and hydrogen (δ2Hleaf) isotopes of leaf water act as a bridge that connects the hydroclimate to plant-derived organic matter. However, it remains unclear whether source (i.e., twig water, soil precipitation) or meteorological parameters temperature, relative humidity, are dominant controls on δ18Oleaf δ2Hleaf. Here, we reported seasonal analysis δ2Hleaf together with from potential waters along an elevation transect Chinese Loess Plateau. We found values were more closely correlated than values, whereas similarly transect. Dual-isotope showed associated because their similar altitudinal responses, generating well-defined isotope line local meteoric (LMWL). also compared measured predicted by Craig–Gordon model no significant differences between them. demonstrate first-order control was second-order enrichment biochemical environmental factors

Language: Английский

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Tracing and Closing the Water Balance in a Vegetated Lysimeter

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(4)

Published: March 22, 2021

Abstract Closure of the soil water balance is fundamental to ecohydrology. But closing with hydrometric information offers no insight into age distribution transiting column via deep drainage or combination evaporation and transpiration. This a major challenge in our discipline currently; tracing needed next step. Here we report results from controlled tracer experiment aimed at both its individual components. was carried out on 2.5 m 3 lysimeter planted willow tree. We applied 25 mm isotopically enriched top tracked it for 43 days through water, bottom drainage, plant xylem. then destructively sampled system quantify remaining isotope mass. More than 900 samples were collected stable analysis trace labeled irrigation. used these data when where irrigation became source uptake percolation. Evapotranspiration dominated outflow (88%). Tracing transpiration flux showed further that had fallen as precipitation 1–2 months prior. The breakthrough complex different curves observed within drainage. Given lack direct experimental travel time transpiration, provide first closure all relevant outflows are traced.

Language: Английский

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Water uptake dynamics in apple trees assessed by an isotope labeling approach

Agricultural Water Management, Journal Year: 2022, Volume and Issue: 266, P. 107572 - 107572

Published: March 5, 2022

Improving our knowledge on the relative contribution of irrigation water, precipitation, and groundwater to tree transpiration is necessary for an efficient sustainable use water resources in agriculture. For this purpose, we applied deuterium (2H) enriched trace uptake by apple trees under field pot conditions. 2H-enriched was supplied Alpine valley mimicking sprinkler irrigation. Labeled infiltration soil presence shoots measured over a week. An ancillary experiment using potted performed elucidate role after saturation with water. Under conditions, infiltrated maximum depth 0.6 m, where most fine roots were present, mixed pre-irrigation Sprinkler taken up 2–4 h its supply shoot content increased first 24 h, then it leveled off. Tree absorbed from layer represented average 48 ± 3% 26 2% total axes leaves, respectively. The results confirmed allowed us speculate that conditions (ca. 0.9 m deep, capillary rise expected depth) did not significantly contribute uptake. Results indicate large fraction (52–74%) derive recent uptake, suggesting rather limited mixing within organs.

Language: Английский

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Tree‐ and stand‐scale variability of xylem water stable isotope signatures in mature beech, oak and spruce

Ecohydrology, Journal Year: 2024, Volume and Issue: 17(2)

Published: Jan. 17, 2024

Abstract In ecohydrology, water isotopologues are used to assess potential sources of root uptake by comparing xylem signatures with source signatures. Such comparisons affected the variability and uncertainty isotope plant sources. The tree‐scale stand‐scale variabilities in stem often unknown but important for sampling design estimation assessing tree uptake. Here, we quantified beech, oak spruce trees a mature forest on Swiss plateau. For water, sub‐daily replicates different cardinal directions showed no systematic differences, found differences height. observed at heights along suggests that residence times within need be considered, their effects compartments (stem, branches, leaves). Further, concerning hydrogen signatures, height‐ species‐specific offsets (SW‐excess δ 2 H). Stem water's was similar magnitude its smaller than branch bulk soil around each tree. Xylem from cores close ground, therefore, can give more precise estimate isotopic signal most recent facilitate accurate attribution.

Language: Английский

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Tracing plant source water dynamics during drought by continuous transpiration measurements: An in‐situ stable isotope approach

Plant Cell & Environment, Journal Year: 2022, Volume and Issue: 46(1), P. 133 - 149

Published: Oct. 28, 2022

The isotopic composition of xylem water (δX ) is considerable interest for plant source studies. In-situ monitored transpired (δT could provide a nondestructive proxy δX -values. Using flow-through leaf chambers, we 2-hourly δT -dynamics in two tropical species, one canopy-forming tree and understory herbaceous species. In an enclosed rainforest (Biosphere 2), observed response to experimental severe drought, followed by 2 H deep-water pulse applied belowground before starting regular rain. We also sampled branches obtain -values from cryogenic vacuum extraction (CVE). Daily flux-weighted δ18 OT were good OX under well-watered drought conditions that matched the rainforest's source. Transpiration-derived mostly lower than CVE-derived values. δ2 HX relatively high compared consistently higher values during drought. Tracing real-time showed distinct uptake transport responses: fast strong contribution deep canopy transpiration contrasting with slow limited species transpiration. Thus, in-situ method promising tool capture rapid dynamics use both woody nonwoody

Language: Английский

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