Journal of Hydrology, Journal Year: 2020, Volume and Issue: 593, P. 125811 - 125811
Published: Dec. 1, 2020
Language: Английский
New Phytologist, Journal Year: 2024, Volume and Issue: 241(5), P. 2009 - 2024
Published: Jan. 5, 2024
Summary A fundamental assumption when using hydrogen and oxygen stable isotopes to understand ecohydrological processes is that no isotope fractionation occurs during plant water uptake/transport/redistribution. growing body of evidence has indicated in certain environments or for species. However, whether the source offset (δ 2 H offset) a common phenomenon how it varies among different climates functional types remains unclear. Here, we demonstrated presence positive, negative, zero offsets based on extensive observations 12 species 635 paired isotopic compositions along strong climate gradient within an inland river basin. Both temperature relative humidity affected δ offsets. In cool moist environments, mainly negatively due its role physiological activity. warm dry offsets, likely by impacting leaf stomatal conductance. These also showed substantial linkages with 18 O enrichment, indicator transpiration evaporative demand. Further studies focusing ecophysiological biochemical understanding dynamics under specific are essential regional conducting paleoclimate reconstructions.
Language: Английский
Citations
10
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
Citations
10
Biogeosciences, Journal Year: 2020, Volume and Issue: 17(19), P. 4853 - 4870
Published: Oct. 13, 2020
Abstract. Stable isotopologues of water are widely used to derive relative root uptake (RWU) profiles and average RWU depth in lignified plants. Uniform isotope composition plant xylem (δxyl) along the stem length woody plants is a central assumption tracing approach which has never been properly evaluated. Here we evaluate whether strong variation δxyl within exists using empirical field observations from French Guiana, northwestern China, Germany. In addition, supported by mechanistic hydraulic model, test hypotheses on how can develop through effects diurnal RWU, sap flux density, diffusion, various other soil parameters The hydrogen oxygen shows temporal (i.e., sub-daily) spatial stem) ranging up 25.2 ‰ 6.8 for δ2H δ18O, respectively, greatly exceeding measurement error range all evaluated datasets. Model explorations predict that significant could arise fluctuations vertical heterogeneity. Moreover, differences emerge between individuals differ only densities or monitored at different times heights. This work complex pattern transport soil–root–xylem system be related dynamics These complicate assessment when stable but also open new opportunities study drought responses environmental drivers. We propose including monitoring flow matric potential more robust estimates expansion attainable insights strategies responses.
Language: Английский
Citations
66
Water Resources Research, Journal Year: 2020, Volume and Issue: 56(11)
Published: Oct. 24, 2020
Abstract The spatiotemporal dynamics of plant water sources are hidden and poorly understood. We document source use Quercus garryana growing in Northern California on a profile approximately 50 cm soil underlain by 2–4 m weathered bedrock (sheared shale mélange) that completely saturates winter, when the oaks lack leaves, progressively dries over summer. determined oak combining observations stable isotope composition, vadose zone moisture groundwater dynamics, metrics tree status (potential) (sapflow). During spring, xylem is isotopically similar to seasonal shallow, evaporatively enriched pools. However, as soils dry table recedes permanently saturated, anoxic, low‐conductivity fresh boundary, Q. shifts using with depleted isotopic composition matches residual deep underlying zone. Sapflow rates remain high late‐summer predawn potentials drop below − 2.5 MPa. Neutron probe surveys reveal rock declines under contrast constant levels grass‐dominated areas. therefore conclude temporarily it occupies but otherwise unsaturated after recedes. ample moisture, connected porosity, oxygenated conditions make key resource during long summer season local Mediterranean climate.
Language: Английский
Citations
60
Rapid Communications in Mass Spectrometry, Journal Year: 2021, Volume and Issue: 36(5)
Published: Dec. 4, 2021
New methods to measure stable isotopes of soil and tree water directly in the field enable us increase temporal resolution obtained data advance our knowledge on dynamics plant fluxes. Only few applications exist. However, these are needed further improve novel hence exploit their full potential.We tested borehole equilibration method collected situ destructive samples soil, trunk root xylem over a 2.5-month experiment tropical dry forest under natural abundance conditions following labelled irrigation. Water from was extracted using cryogenic vacuum extraction. Isotope ratios were determined with IRIS instruments cavity ring-down spectroscopy both laboratory.In general, timelines agreed well for samples. Irrigation heavy hydrogen clearly impacted isotope composition one two studied species. Inter-method deviations increased consequence labelling, which revealed different capabilities cover spatial heterogeneities.We applied remote location. Our reinforced potential this measuring trunks roots confirmed reliability gas permeable probes. measurements should be developed reduce uncertainty within range potential.
Language: Английский
Citations
52
Hydrology and earth system sciences, Journal Year: 2021, Volume and Issue: 25(8), P. 4513 - 4530
Published: Aug. 23, 2021
Abstract. Tree water uptake processes and ecohydrological travel times have gained more attention in recent studies. In situ measurement techniques for stable isotopes offer great potential to investigate these but not been applied much tree xylem soils so far. Here, we used probes isotope measurements monitor the isotopic signatures of soil before after two deuterium-labeled irrigation experiments. To show method, tested our approach with 20-year-old trees three different species (Pinus pinea, Alnus incana Quercus suber). They were planted large pots homogeneous order semi-controlled experimental conditions. Additional destructive sampling plant material allowed a comparison between (cryogenic vacuum extraction direct vapor equilibration) measurements. Furthermore, isotope-tracer-based compared derived from sap flow The time first arrival tracer signals at 15 cm stem hight ca. 17 h all matched well sap-flow-based times. However, 150 height tracer-based differed ranged 2.4 3.3 d. Sap-flow-based 1.3 d longer than signature notably, which suggests that types sampled pools. consistent (on average standard deviations smaller by 8.4 ‰ δ2H 1.6 δ18O measurements) also among same pot methods 7.8 δ18O, respectively). Our study demonstrates large-scale experiments very frequent monitoring It shows differences or sensor need be considered when comparing results studies within one using methods.
Language: Английский
Citations
48
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
Citations
42
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
Citations
37
Hydrology and earth system sciences, Journal Year: 2022, Volume and Issue: 26(15), P. 4125 - 4146
Published: Aug. 8, 2022
Abstract. Isotope-based approaches to study plant water sources rely on the assumption that root uptake and within-plant transport are non-fractionating processes. However, a growing number of studies have reported offsets between source stable isotope composition for wide range ecosystems. These isotopic can result in erroneous attribution used by plants potential overestimations groundwater vegetation. We conducted global meta-analysis quantify magnitude these explored whether their variability could be explained either biotic or abiotic factors. Our database compiled 112 spanning arctic tropical biomes dual (δ2H δ18O) (stem) water, including soil (sampled following various methodologies along variable depths). calculated 2H two ways: line conditioned excess (LC-excess) describes deviation from local meteoric (SW-excess) line, each sampling campaign within study. tested effects climate (air temperature content), class, traits (growth form, leaf habit, wood density, parenchyma fraction mycorrhizal habit) LC-excess SW-excess. Globally, stem was more depleted than (SW-excess < 0) 3.02±0.65 ‰ (P 0.05 according estimates our linear mixed model weighted sample size studies). In 95 % cases where SW-excess negative, indicating had not undergone evaporative enrichment (such as groundwater) unlikely explain observed soil–plant offsets. Soil class did any significant effect negative cold wet sites, whereas it positive warm sites. The climatic suggest methodological artefacts sole cause results would imply may lead inaccuracies when using bulk proxy infer sources.
Language: Английский
Citations
35
Hydrological Processes, Journal Year: 2022, Volume and Issue: 36(10)
Published: Sept. 12, 2022
Abstract Ecohydrological investigations commonly use the stable isotopes of water (hydrogen and oxygen) as conservative ecosystem tracers. This approach requires accessing analysing from plant soil matrices. Generally, there are six steps involved to retrieve hydrogen oxygen isotope values these matrices: (1) sampling, (2) sample storage transport, (3) extraction, (4) pre‐analysis processing, (5) isotopic analysis, (6) post‐processing correction. At each step, cumulative errors can be introduced which sum non‐trivial magnitudes. These impact subsequent interpretations about cycling partitioning through soil–plant‐atmosphere continuum. steps, multiple possible options select resulting in tens thousands combinations used by researchers go samples data. In a newly emerging field, so many create interpretive confusion major issues with data comparability. points need for development shared standardized approaches. Here we critically examine state process chain, reflecting on associated provide suggestions move our community towards standardization. Assessing this ‘process chain’ will help us see problem its entirety facilitate action agreed upon
Language: Английский
Citations
34