scholarly journals Contrasting Water Use Strategies of Tamarix ramosissima in Different Habitats in the Northwest of Loess Plateau, China

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2791
Author(s):  
Pengyan Su ◽  
Mingjun Zhang ◽  
Deye Qu ◽  
Jiaxin Wang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Loess Plateau ◽  
Meteoric Water ◽  
Water Source ◽  
Water Sources ◽  
Tamarix Ramosissima ◽  
Water Line ◽  
Meteoric Water Line ◽  
Utilization Ratio

As a species for ecological restoration in northern China, Tamarix ramosissima plays an important role in river protection, flood control, regional climate regulation, and landscape construction with vegetation. Two sampling sites were selected in the hillside and floodplain habitats along the Lanzhou City, and the xylems of T. ramosissima and potential water sources were collected, respectively. The Bayesian mixture model (MixSIAR) and soil water excess (SW-excess) were applied to analyze the relationship on different water pools and the utilization ratios of T. ramosissima to potential water sources in two habitats. The results showed that the slope and intercept of local meteoric water line (LMWL) in two habitats were smaller compared with the global meteoric water line (GMWL), which indicated the existence of drier climate and strong evaporation in the study area, especially in the hillside habitat. Except for the three months in hillside, the SW-excess of T. ramosissima were negative, which indicated that xylems of T. ramosissima are more depleted in δ2H than the soil water line. In growing seasons, the main water source in hillside habitat was deep soil water (80~150 cm) and the utilization ratio was 63 ± 17% for T. ramosissima, while the main water source in floodplain habitat was shallow soil water (0~30 cm), with a utilization ratio of 42.6 ± 19.2%, and the water sources were different in diverse months. T. ramosissima has a certain adaptation mechanism and water-use strategies in two habitats, and also an altered water uptake pattern in acquiring the more stable water. This study will provide a theoretical basis for plant water management in ecological environment protection in the Loess Plateau.

Apple trees, larches and their water uptake: distinct ecohydrological systems in contrasting environmental settings?

2021 ◽  
Author(s):  
Stefano Brighenti ◽  
Giacomo Bertoldi ◽  
Agnese Aguzzoni ◽  
Damiano Zanotellii ◽  
Nikolaus Obojes ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Samples ◽  
Meteoric Water ◽  
Stream Water ◽  
Water Sources ◽  
Apple Trees ◽  
Water Line ◽  
Meteoric Water Line ◽  
Different Depths ◽  
Different Water Sources

<p>Different water sources can contribute to plant transpiration in Alpine environments, such as rainfall, snowmelt, irrigation and/or stream waters that are temporarily stored in the vadose and saturated zones. Particularly, the proportion of water uptake from different soil depths can strikingly differ depending on the species and the local environmental conditions such as the availability of freshwater resources, and local climatic and pedological settings.</p><p>We aim at estimating the relative contributions of different water sources (i.e., soil water at various depths and groundwater) to tree transpiration with the use of stable water isotopes. Our work is part of a wider national project (WATZON: WATer mixing in the critical ZONe) studying the relationship between plants, soil and water in contrasting natural and semi-natural environments of Italy. Here we report the results of monitoring activities in two different ecosystems in South-Tyrol (Eastern Italian Alps): an apple orchard growing on a deep (>2.5 m) sandy soil of the Adige floodplain (Binnenland), and a sub-alpine conifer forest located on steep slopes with a shallow (10-60 cm) skeletal soil (Mazia, 2000 mt a.s.l.), where we selected European larch (Larix decidua) as a model-species. Water (precipitation, stream water, groundwater), soil at different depths and twigs samples were collected fortnightly from May to November 2020, and weather conditions (automatic stations), soil parameters (moisture and temperature) at different depths and sapflow were continuously recorded over the entire period.</p><p>At both locations, precipitation waters had a heavier isotopic composition than stream water and groundwater, that did not show any significant difference between each other in terms of isotopic signature. While all these potential water sources plotted on the local meteoric water line, shallow soil water samples (5-15 cm) deviated from it revealing a stronger and more variable evaporative fractionation when compared with those of deeper soil (25-65 cm). Xylem water samples from apple trees at Binnenland overlapped with soil water samples, more consistently at 10-30 cm depths. This water mostly derived from infiltrated rainwater but with a non-negligible contribution from groundwater during July and August. In contrast, xylem water from larch trees at Mazia plotted on the local meteoric water line, and had an isotopic composition more similar to that of precipitation than soil water even for samples collected after several days of drying out. As sapflow measurements of larches revealed a continuous transpiration, it is unlikely that trees took up water only soon after precipitation events. Instead, we hypothesize that larches at Mazia likely rely on a water pool which is different from the soil (e.g., rock moisture).</p><p>These contrasting ecohydrological systems reveal different strategies of water use by dwelling plants in natural and anthropic systems, showing a distinct sensitivity and resilience to changing climate.</p>

Stable isotope tracers as diagnostic tools in studying water sources in a humid bamboo watershed during the plum rainfall events

Water Policy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 368-381
Author(s):  
Jianfeng Gou ◽  
Simin Qu ◽  
Peng Shi ◽  
Dachen Li ◽  
Xueqiu Chen ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Temporal Variation ◽  
Soil Water ◽  
Meteoric Water ◽  
Water Sources ◽  
Rainfall Events ◽  
Water Line ◽  
Isotopic Variation ◽  
Meteoric Water Line

Abstract This study investigates the temporal variation of stable isotopic composition in precipitation, soil water, and streamflow water during the plum rainfall events in an upland headwater watershed which is mainly covered with bamboo. The results show that the isotopic composition of various water sources exhibit significant temporal variation. The local meteoric water line is established by using the relationship between the stable isotope of oxygen-18 and deuterium, which is slightly different from the meteoric water line of China. The isotopic temporal variation of precipitation is closely related to exchange effect between raindrops and environmental vapor, evaporation fractionation and rainfall intensity. The isotopic variation of shallow soil water is mainly determined by canopy interception, ground evaporation and the mixing with pre-event water; as for the isotopic variation of deep soil water, it is virtually influenced by pre-event water. The most enriched isotopic composition of streamflow and deuterium excess (d-excess) differences between streamflow and rainfall both indicate that streamflow is recharged not only by event water but also by pre-event water. Hence, a better understanding of precipitation formation and the hydrological response under the plum rainfall system may be instructive for the management of water resources in humid watersheds in southern China.

Water use strategy of Ammopiptanthus mongolicus community in a drought year on the Mongolian Plateau

2020 ◽  
Vol 13 (6) ◽  
pp. 793-800
Author(s):  
Ya-Juan Zhu ◽  
Guo-Jie Wang ◽  
Zhi-Ming Xin
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Source ◽  
Water Sources ◽  
Desert Ecosystem ◽  
Total Water ◽  
Mongolian Plateau ◽  
Ammopiptanthus Mongolicus ◽  
Deep Soil ◽  
Water Use Strategy

Abstract Aims In desert ecosystems, water is a restricting factor for plant growth and vegetation dynamics. The relatively stable water source from deep soil profile or groundwater is important for plant survival during drought. Understanding water use strategy of endangered species, in desert ecosystem is essential for their conservation and restoration such as Ammopiptanthus mongolicus on the Mongolian Plateau. Methods The stable isotope method of δD and δ 18O was used to examine the main water sources of A. mongolicus and two companion shrubs, e.g. Artemisia ordosica and Artemisia xerophytica. The contribution of different water sources to each species was calculated by IsoSource model. Leaf δ 13C was used to compare long-term water use efficiency of three shrubs. Soil moisture and root distribution of three shrubs was measured to explain plant water use strategy. Important Findings The results showed that A. mongolicus relied on groundwater and 150–200 cm deep soil water, with the former contributing to almost half of its total water source. Artemisia ordosica mainly used 150–200 cm deep soil water, but also used shallow soil water within 100 cm in summer and autumn. Artemisia xerophytica mainly used 150–200 cm deep soil water and groundwater, with the latter contributing to about 30%–60% of its total water source. The three shrubs had dimorphic or deep root systems, which are in accord with their water sources. The WUE in the evergreen shrub A. mongolicus was higher than in two deciduous Artemisia shrubs, which may be an adaptive advantage in desert ecosystem. Therefore, groundwater is an important water source for the endangered shrub A. mongolicus in a drought year on Mongolian Plateau. Ammopiptanthus mongolicus and two Artemisia shrubs competed for deep soil water and groundwater.

scholarly journals Intensified Interspecific Competition for Water after Afforestation with Robinia pseudoacacia into a Native Shrubland in the Taihang Mountains, Northern China

2021 ◽  
Vol 13 (2) ◽  
pp. 807
Author(s):  
Wanrui Zhu ◽  
Wenhua Li ◽  
Peili Shi ◽  
Jiansheng Cao ◽  
Ning Zong ◽  
...  
Keyword(s):  
Soil Water ◽  
Introduced Species ◽  
Water Use ◽  
Rainy Season ◽  
Robinia Pseudoacacia ◽  
Water Source ◽  
Total Water ◽  
Mountainous Areas ◽  
Water Competition ◽  
Seasonal Water Use

Understanding how soil water source is used spatiotemporally by tree species and if native species can successfully coexist with introduced species is crucial for selecting species for afforestation. In the rocky mountainous areas of the Taihang Mountains, alien Robinia pseudoacacia L. has been widely afforested into the native shrublands dominated by Ziziphus jujuba Mill var. spinosa and Vitex negundo L. var. heterophylla to improve forest coverage and soil nutrients. However, little is known about the water relation among species, especially seasonal water use sources in different microsites. We selected the soil and plant xylem samples of two opposite microtopographic sites (ridge and valley) monthly in the growth season to analyze isotope composition. The proportions of water sources were quantified by the MixSIAR model and compared pairwise between species, microsites and seasons. We found that deep subsoil water at a depth of 40–50 cm contributed up to 50% of the total water uptake for R. pseudoacacia and Z. jujuba in the growing season, indicating that they stably used deeper soil water and had intense water competition. However, V. negundo had a more flexible water use strategy, which derived more than 50% of the total water uptake from the soil layer of 0–10 cm in the rainy season, but majorly captured soil water at a depth of 30–50 cm in the dry season. Therefore, high niche overlaps were shown in V. negundo with the other two species in the dry season, but niche segregation was seen in the rainy season. The microtopographic sites did not shift the seasonal dynamic of the water source use patterns of the three studied species, but the water use niche overlap was higher in the valley than in the ridge. Taken together, the introduced species R. pseudoacacia intensified water competition with the native semi-arbor species Z. jujuba, but it could commonly coexist with the native shrub species V. negundo. Therefore, our study on seasonal water use sources in different microsites provides insight into species interaction and site selection for R. pseudoacacia afforestation in the native shrub community in rocky mountainous areas. It is better to plant R. pseudoacacia in the shrubland in the valley so as to avoid intense water competition and control soil erosion.

scholarly journals Global perspective of local meteoric water lines based on daily and monthly data: a consideration of climate types

2021 ◽  
Author(s):  
Yang Song ◽  
Shengjie Wang ◽  
Athanassios Argiriou ◽  
Mingjun Zhang ◽  
Yudong Shi
Keyword(s):  
Least Squares ◽  
Meteoric Water ◽  
Major Axis ◽  
Ordinary Least Squares ◽  
Weighted Regression ◽  
Precipitation Data ◽  
Monthly Data ◽  
Water Line ◽  
Meteoric Water Line ◽  
Event Based

The stable hydrogen and oxygen isotopes as well as their correlation in precipitation have been widely investigated for the understanding of various hydrological processes. Monthly precipitation data were usually recommended in order to establish a linear relationship between the stable hydrogen and oxygen isotope ratios (also known as local meteoric water lines or LMWL for a specific location); however, the LMWL based on daily (or event-based) precipitation data is usually different from that using monthly data. Based on 83 sampling stations across the world from 2000 to 2017, local meteoric water lines were calculated using daily (or event-based) precipitation data (n=9354) and corresponding monthly data (n=1895), respectively; multiple regression methods were used, including ordinary least squares, reduced major axis and major axis regressions as well as their precipitation-weighted counterparts. The global meteoric water line from daily data is δ2H = (7.72 ± 0.02) δ18O + (6.84 ± 0.15) (n=9354, r2=0.96) and from monthly data is δ2H = (7.81 ± 0.04) δ18O+(7.61 ± 0.32) (n=1895, r2=0.96). The stations used in this study were grouped into five climate types, according to the Köppen Climate classification. The precipitation-weighted regression may increase the long-term receptiveness of LMWL using daily-based (or event-based) samples, not only for arid regions, but also for cold regions. When only relatively short-term isotopic records in event-based precipitation samples are available, which is usual in modern hydrological studies, the weighted regression (especially precipitation weighted ordinary least squares regression, PWLSR) is helpful to create a respective local meteoric water line.

scholarly journals Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in the Na-Cl brackish waters of northwestern Sardinia, Italy

2013 ◽  
Vol 17 (7) ◽  
pp. 2917-2928 ◽  
Author(s):  
G. Mongelli ◽  
S. Monni ◽  
G. Oggiano ◽  
M. Paternoster ◽  
R. Sinisi
Keyword(s):  
Coastal Aquifers ◽  
Meteoric Water ◽  
Major Ions ◽  
Mediterranean Islands ◽  
Rock Interaction ◽  
Water Line ◽  
Brackish Waters ◽  
Meteoric Water Line ◽  
The Mediterranean ◽  
Water Rock Interaction

Abstract. Throughout the Mediterranean, salinization threatens water quality, especially in coastal areas. This salinization is the result of concomitant processes related to both seawater intrusion and water–rock interaction, which in some cases are virtually indistinguishable. In the Nurra region of northwestern Sardinia, recent salinization related to marine water intrusion has been caused by aquifer exploitation. However, the geology of this region records a long history from the Palaeozoic to the Quaternary, and is structurally complex and comprises a wide variety of lithologies, including Triassic evaporites. Determining the origin of the saline component of the Jurassic and Triassic aquifers in the Nurra region may provide a useful and more general model for salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activity and recent climatic change, the Nurra has become vulnerable to desertification and, in common with other Mediterranean islands, surface water resources periodically suffer from severe shortages. With this in mind, we report new data regarding brackish and surface waters (outcrop and lake samples) of the Na-Cl type from the Nurra region, including major ions and selected trace elements (B, Br, I, and Sr), in addition to isotopic data including δ18O, δD in water, and δ34S and δ18O in dissolved SO4. To identify the origin of the salinity more precisely, we also analysed the mineralogical and isotopic composition of Triassic evaporites. The brackish waters have Cl contents of up to 2025 mg L−1 , and the ratios between dissolved ions and Cl, with the exception of the Br / Cl ratio, are not those expected on the basis of simple mixing between rainwater and seawater. The δ18O and δD data indicate that most of the waters fall between the regional meteoric water line and the global meteoric water line, supporting the conclusion that they are meteoric in origin. A significant consequence of the meteoric origin of the Na-Cl-type water studied here is that the Br / Cl ratio, extensively used to assess the origin of salinity in fresh water, should be used with care in carbonate aquifers that are near the coast. Overall, δ34S and δ18O levels in dissolved SO4 suggest that water–rock interaction is responsible for the Na-Cl brackish composition of the water hosted by the Jurassic and Triassic aquifers of the Nurra, and this is consistent with the geology and lithological features of the study area. Evaporite dissolution may also explain the high Cl content, as halite was detected within the gypsum deposits. Finally, these Na-Cl brackish waters are undersaturated with respect to the more soluble salts, implying that in a climate evolving toward semi-arid conditions, the salinization process could intensify dramatically in the near future.

scholarly journals Isotopes of oxygen-18 and deuterium in precipitation in Slovakia / Izotopy kyslíka-18 A deutéria v zrážkach na Slovensku

2012 ◽  
Vol 60 (4) ◽  
pp. 265-276 ◽  
Author(s):  
Ladislav Holko ◽  
Michal Dóša ◽  
Juraj Michalko ◽  
Martin Šanda
Keyword(s):  
Isotopic Composition ◽  
Air Temperature ◽  
Meteoric Water ◽  
Precipitation Amount ◽  
Data Series ◽  
Water Line ◽  
Temperature And Precipitation ◽  
Meteoric Water Line ◽  
The Mean ◽  
Available Information

The article synthesizes available information on isotopic composition of precipitation in Slovakia (the Western Carpathians). Monthly δ18O data from eleven stations and period 1988-1997 were used to investigate correlations among the stations, altitude, air temperature and precipitation amount effects. The mean annual altitude and air temperature gradients of δ18O in precipitation were 0.21‰/100 m and 0.36‰/1°C, respectively. Maps of spatial distribution of mean annual δ18O in precipitation based on both gradients were constructed. The two maps do not significantly differ for the majority of Slovakia. δ2H data were available for only three stations. Local meteoric water line derived for the station with the longest data series (δ2H = = 7.86δ18O + 6.99) was close to the Global Meteoric Water line. Its parameters in periods 1991-1993 and 1991-2008 did not change. The study indicates that a more detailed monitoring of isotopic composition of precipitation in mountains should be carried out in the future. The highest station exhibited very small seasonal variability of δ18O in precipitation compared to other Slovak stations. The second highest mountain station had significantly higher deuterium excess than the neighboring stations located in the valley. In some analyses the data from the nearest stations situated abroad (Vienna, Krakow) were used.

Interactions between 2H and 18O natural abundance variations and DLW measurements of energy expenditure

1996 ◽  
Vol 271 (2) ◽  
pp. E302-E308 ◽  
Author(s):  
P. Ritz ◽  
T. J. Cole ◽  
P. S. Davies ◽  
G. R. Goldberg ◽  
W. A. Coward
Keyword(s):  
Energy Expenditure ◽  
Dose Level ◽  
Meteoric Water ◽  
Natural Abundance ◽  
Doubly Labeled Water ◽  
Water Line ◽  
Optimal Ratio ◽  
Meteoric Water Line ◽  
Within Subjects

Appropriate corrections for 2H and 18O natural abundance are necessary in energy expenditure measurements with the doubly labeled water (DLW) method. The contribution of natural abundance variations to errors in the method is generally ignored if an appropriate dose level is given. Calculation of the appropriate dose level assumes that 2H and 18O natural abundance values are covariant and have a fixed slope. This study has investigated the between- and within-subject natural abundance variations, the latter over periods of time similar to those used in DLW experiment. Although 2H and 18O natural abundance values are covariant between subjects, the slope of their relationship is different from that of the Meteoric Water Line. Within subjects there is no such demonstrable covariance. It is concluded that: 1) the determinants of 2H and 18O natural abundance are different within and between subjects; 2) the concept of an optimal ratio of doses is not valid, and a safer strategy is probably to use a ratio > 10; 3) natural abundance variations may contribute significantly to the magnitude of error in the DLW measurements of energy expenditure.

scholarly journals Contribution of glacial melt to river runoff as determined by stable isotopes at the source region of the Yangtze River, China

2015 ◽  
Vol 47 (2) ◽  
pp. 442-453 ◽  
Author(s):  
Zhaofei Liu ◽  
Zhijun Yao ◽  
Rui Wang
Keyword(s):  
Yangtze River ◽  
Meteoric Water ◽  
Stream Water ◽  
Source Region ◽  
Upstream Region ◽  
The Yangtze River ◽  
Hydrograph Separation ◽  
Water Line ◽  
Total Runoff ◽  
Meteoric Water Line

The primary objective of this study was to quantify the contribution of glacial melt to total runoff in the Gaerqu River catchment, which is located in the source region of the Yangtze River, China. The isotope hydrograph separation method was used to separate glacier melt runoff from total runoff in the catchment. The degree-day method was used to investigate temporal variations in glacial melt runoff. The results showed that the contribution of glacial melt runoff to total runoff was 15.0%. The uncertainty of the separation was ± 3.7% at the confidence level of 95%. Glacial melt runoff was mainly generated in June, July, and August. The runoff coefficient was 0.23 for the catchment. Precipitation-induced runoff constituted 19.9% of the total precipitation, meaning that precipitation loss was >80% across the study period (a hydrological year). The Local Meteoric Water Line (LMWL) of the catchment was fitted as δ2H = 7.75 δ18O + 5.93. This line has a smaller slope and intercept than the Global Meteoric Water Line. The regression-lines for the δ18O and δ2H values of stream water indicated that evaporation was greater over the entire catchment than it was for the upstream region alone.

Sign in / Sign up

Export Citation Format

Share Document