Validation of a coupled <i>δ</i><sup>2</sup>H<sub><i>n</i>-alkane</sub>–<i>δ</i><sup>18</sup>O<sub>sugar</sub> paleohygrometer approach based on a climate chamber experiment

Biogeosciences, Journal Year: 2021, Volume and Issue: 18(19), P. 5363 - 5380

Published: Oct. 4, 2021

Abstract. The hydrogen isotope composition of leaf-wax-derived biomarkers, e.g., long-chain n-alkanes (δ2Hn-alkane), is widely applied in paleoclimate. However, a direct reconstruction the source water based on δ2Hn-alkane alone challenging due to enrichment heavy isotopes during evaporation. coupling with δ18O hemicellulose-derived sugars (δ18Osugar) has potential disentangle this limitation and additionally allow relative humidity reconstructions. Here, we present as well δ18Osugar results obtained from leaves Eucalyptus globulus, Vicia faba, Brassica oleracea, which grew under controlled conditions. We addressed questions (i) whether values reconstructions leaf composition, (ii) how accurately reconstructed enables (RH) reconstruction, (iii) robust calculation. For all investigated species, n-alkane n-C29 was most abundant therefore used for compound-specific δ2H measurements. n-C31 could be evaluated robustly. Regarding monosaccharides, arabinose xylose were abundant, their calculate weighted mean values. Both yielded significant correlations δ2Hleaf δ18Oleaf water, respectively (r2=0.45 0.85, respectively; p<0.001, n=24). Mean fractionation factors between biomarkers found −156 ‰ (ranging −133 −192 ‰) εn-alkane/leaf +27.3 +23.0 32.3 εsugar/leaf respectively. Modeled RHair Craig–Gordon model using measured Tair, input correlate highly significantly modeled (R2=0.84, RMSE = 6 %). When values, correlation weaker but still significant, R2=0.54 (p<0.001, 10 Finally, (δ2Hs δ18Os) calculated our coupled approach matches climate chamber experiment (δ2Htank δ18Otank water). This highlights great δ2Hn-alkane–δ18Osugar paleohygrometer paleoclimate

Language: Английский

---

Leaf water δ

Functional Plant Biology, Journal Year: 2021, Volume and Issue: 48(7), P. 732 - 742

Published: May 21, 2021

The distributions of CAM and C3 epiphytic bromeliads across an altitudinal gradient in western Panama were identified from carbon isotope (δ13C) signals, epiphyte water balance was investigated via oxygen isotopes (δ18O) wet dry seasons. There significant seasonal differences leaf (δ18Olw), precipitation, stored ‘tank’ vapour. Values δ18Olw evaporatively enriched at low altitude the season for epiphytes, associated with relative humidity (RH) during day. Crassulacean acid metabolism (CAM) values relatively depleted, consistent vapour uptake gas exchange under high RH night. At altitude, cloudforest locations, also reflected by A mesocosm experiment Tillandsia fasciculata Werauhia sanguinolenta (C3) combined simulations using a non-steady-state model. For both bromeliads, became progressively depleted saturating day night, although evaporative enrichment restored W. Source overlapping base modified δ18O exchanges. results demonstrate how stable provide insights atmospheric exchanges systems.

Language: Английский

---

Determinación del aporte de agua y de la profundidad de las raíces activas de plantas leñosas mediante un trazador de deuterio en un sitio de Savannah en el norte de la cuenca de Stampriet, Namibia

Hydrogeology Journal, Journal Year: 2023, Volume and Issue: 32(1), P. 189 - 201

Published: Nov. 14, 2023

Abstract Woody plants play a significant role in the global water cycle through uptake by roots and evapotranspiration. A deuterium tracer was used to assess active root depths for Salvia mellifera Boscia albitrunca Ebenhaezer area (western Namibia). The inserted at different soil December 2016. Xylem cores were obtained using an increment borer, transpired collected transpiration bags zipped around plants’ leaves. Groundwater from boreholes. Soil samples after rainy season hand auger. extracted cryogenic vacuum extraction method analysed stable isotopes. Only one S. sample showed high content (516‰) where 2.5-m depth. Elevated contents observed two xylem samples; had been applied 2.5 3 m depth (yielding 35 31‰ deuterium, respectively), which constitutes possible active-root range . At end of study period (May 2017), average δ 18 O value B. similar that groundwater. between groundwater, indicating this species uses groundwater available recharge. Determination source these would help improve hydrological modelling incorporating influence woody on

Language: Английский

---

Hydrological mass balance of boreal watersheds in the Canadian Shield

Journal of Hydrology, Journal Year: 2022, Volume and Issue: 612, P. 128236 - 128236

Published: July 28, 2022

Language: Английский

---

Ecohydrological Dynamics and Temporal Water Origin in a European Mediterranean Vineyard

Ecohydrology, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 2, 2024

ABSTRACT Viticulture is an essential sector in agriculture as wine production plays a vital role the socio‐economic life of many countries, especially Mediterranean area. Grapevines are valuable, long‐lived species able to grow hot and dry regions. We currently do not know whether rain‐fed grapevines entirely rely on deep soil water or make substantial use shallow from summer precipitation events. Without knowing this, we poorly understand what fraction inputs contributes grapevine transpiration. This has implications for how quantify grapevine‐relevant budgets predicting impacts climate change grape production. investigated vineyard Chianti region, central Italy. During growing season 2021, monitored moisture at 30‐ 60‐cm depth. collected over 250 samples stable isotope analysis rainfall, soil, plants. Since traditional plant sampling problematic grapevines, shoots, leaves, condensed leaf transpiration after sealed plastic bags were wrapped around shoot. these alternative reconstruct isotopic signal xylem infer plant's seasonal origin throughout season. The revealed that, season, received disproportional contributions by rain that had fallen winter, even when compensating Only late did amounts whose contribution occasionally became dominant. These results provide better understanding ecohydrological interactions uptake dynamics valuable agroecosystems such vineyards.

Language: Английский

---