Enhancing the water use efficiency model predictions for Platycladus orientalis and Quercus variabilis: Integrating the dynamics of carbon dioxide concentration and soil water availability.

Water use efficiency (WUE) is a tracer for plants on the trade-off exchange of water and carbon dioxide between terrestrial ecosystems and the atmosphere; therefore, a dynamic investigation of WUE and its driving factors will be of great significance to optimize water and carbon fitness and predict the plants' response to climate change. In our study, a modified water use efficiency model was proposed to improve the quantification of carbon and water processes by adding a photosynthesis-g simulation dependent on CO concentration and soil moisture to the photosynthetic transpiration model (noted as SMPTSB model). Actual measured water use efficiencies were respectively obtained by the gas exchange measurements (WUE) and the δC that defined as the carbon-heavy isotope of the water-soluble compound in leaves (WUE) of three-year tree saplings of Platycladus orientalis (L.

[Analysis of Temporal and Spatial Carbon Stock Changes and Driving Mechanism in Xinjiang Region by Coupled PLUS-InVEST-Geodector Model].

Based on the goal of "dual-carbon" strategy, it is important to explore the impacts of land use change on carbon stock and the drivers of spatial differentiation of carbon stock in Xinjiang. Here, we predicted the land use types in Xinjiang in 2035 under different scenarios and analyzed the impacts of land use on carbon stock, which is of great theoretical and practical importance for policy formulation, land use structure adjustment, and carbon neutrality target achievement in Xinjiang. The coupled PLUS-InVEST-Geodector model was used to explore the spatial and temporal patterns of carbon stock change under the scenarios of rapid development, natural change, arable land protection, and ecological protection in Xinjiang in 2035 and to quantitatively reveal the attribution of influences on the changes in carbon stock from the perspectives of land use change and the combination of nature-socioeconomic-accessibility.

How has carbon storage changed in the Yili-Tianshan region over the past three decades and into the future? What has driven it to change?

Predicting future land use changes and assessing carbon storage remain challenging. Nowadays, how nature and socioeconomics drive changes in carbon storage is a hot topic in research. In this study, through the projection of land use type and the integration of the PLUS, Integrated Valuation of Ecosystem Services and Trade-offs (InVEST), and Geodetector models, we constructed a framework for assessing carbon storage in different land use scenarios.

[Seasonal variation of water utilization sources and responses to precipitation in the dominant species of broad-leaved and needle-leaved mixed forests in Mount Lushan, China].

Elucidating the seasonal patterns of water sources for dominant species in the sub-tropical humid mountainous forest, analyzing the eco-hydrological complementarity and competition mechanisms among coexisting species, investigating the responses of plant water utilization to precipitation, could provide a theoretical basis for vegetation restoration and management. Based on the stable hydrogen and oxygen isotope technique, we analyzed the δH and δO characteristics of precipitation, xylem water from and , and soil water from 0-100 cm depth in Mount Lushan, China. The MixSIAR model, Levins index, and PS index were used to calculate the relative contribution rate of each water source, the hydrological niche breadth, and niche overlap of and .

[Ecological Environment Assessment and Driving Mechanism Analysis of Nagqu and Amdo Sections of Qinghai-Xizang Highway Based on Improved Remote Sensing Ecological Index].

The ecological environment along the Qinghai-Xizang highway is an important part of the construction of the ecological civilization in the Xizang region, and current research generally suffers from difficulties in data acquisition, low timeliness, and failure to consider the unique "alpine saline" environmental conditions in the study area due to the unique geographical environment of the Qinghai-Xizang plateau. Based on the GEE platform and the unique geographical environment of the study area, the remote sensing ecological index (RSEI) was improved, and a new saline remote sensing ecological index (SRSEI) applicable to the alpine saline region was constructed by using principal component analysis as an ecological environment quality evaluation index. The spatial distribution pattern and temporal variation trend of ecological environment quality along the Qinghai-Xizang Highway Nagqu-Amdo section were analyzed at multiple spatial and temporal scales using the ArcGIS 10.

[Enrichment Characteristics, Source Apportionment, and Risk Assessment of Heavy Metals in the Industrial and Mining Area of Northern Guangdong Province].

In order to understand the heavy metal pollution of the industrial and mining area in northern Guangdong Province, topsoil samples (0-20 cm) from 209 sites in study area were collected, and the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were analyzed. The source and distribution characteristics of Cd, Cr, Hg, Ni, Pb, As, Cu, and Zn in soil samples were analyzed using the geographic information system (GIS) and principal component analysis (PCA), and the geo-accumulation index and potential ecological hazard index were used to evaluate their pollution status and ecological risk. The results showed that:① Except Ni, all seven heavy metal elements exceeded the national soil background value but were below the pollution risk screening value.

[Effects of CO concentration and soil water content on short-term water-use efficiency at whole-plant level].

Uncovering the variations of short-term water-use efficiency (WUE) at whole-plant level in response to CO concentration () and soil water content (SWC) can improve the understanding of plant survival strategies under climate change. In this study, saplings were cultured in simulated climate chambers.There were totally 15 treatments, including of 400 (), 600 () and 800 () μmol·mol and SWC of 35%-45% field water holding capacity (FC), 50%-60%FC, 60%-70%FC, 70%-80%FC and 95%-100%FC.

Soil water stress overrides the benefit of water-use efficiency from rising CO and temperature in a cold semi-arid poplar plantation.

The counteractive effect of atmospheric CO (c ) enrichment and drought stress on tree growth results in great uncertainty in the growth patterns of forest plantations in cold semi-arid regions. We analysed tree ring chronologies and carbon isotopes in Populus simonii plantations in cold semi-arid areas in northern China over the past four decades. We hypothesized that the hydraulic stress from drought would override the stimulating effect of increasing c and temperature (T) on stem growth (basal area increment [BAI]).

[Erosion process of loess slope and influencing factors in the loess hilly-gully region, China].

Rainfall intensity, slope length, and slope gradient are the important factors affecting runoff and sediment yield. In order to quantitatively analyze the effects of rainfall intensity, slope length, and slope gradient on the erosion process of Ansai loess slope in loess hilly and gully region, we analyzed the variation of runoff and sediment yield on Ansai loess with two slope lengths (5, 10 m), three slopes (5°, 10°, 15°) and two rainfall intensities (60, 90 mm·h) in an indoor simulated rainfall experiment. The results showed that the initial runoff generation time decreased with the increases of slope length, though the overall change was not significant.

Effects of thinning intensity on the understory water-holding capacity of var. plantation in the Bashang area of north China.

The complex terrain and poor climatic conditions in Bashang area of Hebei Province result in water and soil loss and geological disasters, which pose a serious threat to ecological safety in North China. In order to improve local environmental quality, barren-resistant and fast-growing tree species such as var. and are planted with large areas.

[Quantitative separation of evapotranspiration components of ecosystem based on multiple isotope models].

To fully understand the changes in the evapotranspiration components in forest ecosystem and their contribution to evapotranspiration at daily scale, we used the hypothesis theory of isotopic steady state and non-steady state combined with the water isotope analyzer system to quantitatively split and compare the evapotranspiration components of ecosystem during the growing season. Results showed that the O of water from different sources during the four mea-surement days (August 5, 8, 10, 11, 2016) all showed surface soil water and oxygen isotope composition (δ) > branch water and oxygen isotope composition (δ) > atmospheric water vapor oxygen isotopes composition (δ), with obvious differences due to the isotope fractionation. Oxygen isotopes composition of soil evaporated water vapor (δ) was between -26.

Effects of watershed char and climate variables on annual runoff in different climatic zones in China.

The complex interactions between climate and watershed characteristics lead to diverse annual runoff responses. Understanding the mechanism by which different climatic and watershed factors affect annual runoff is helpful in understanding the resulting changes in the hydrological process. In this study, the characteristics of 73 watersheds were analyzed.

Comparison of agricultural wastes and synthetic macromolecules as solid carbon source in treating low carbon nitrogen wastewater.

This paper investigated the feasibility of using agricultural wastes and synthetic macromolecules as solid carbon sources and studied the effects of improvement of denitrification by the selected agricultural wastes. The carbon release capacity and denitrification performance of corncob (CC), peanut shell (PS), obsolescent rice (OR) and polycaprolactone (PCL), poly butylene succinate (PBS), polyvinyl alcohol sodium alginate (PVA-SA) were systematically analyzed. The results showed that for each carbon source, the first-order kinetic equation was basically followed during the carbon release process.

[Partitioning ecosystem respiration of a Platycladus orientalis forest in the west mountainous area of Beijing, China using stable carbon isotope].

Based on stable carbon isotope, we quantitatively partitioned ecosystem respiration in a Platycladus orientalis forest in the west mountainous area of Beijing. Results from this study could lay the foundation for carbon exchange research in forest ecosystems of this region. The spectroscopy technique was used to continuously measure CO concentrations and δC values at different height of the forest.

[Simulation of δO in Platycladus orientalis leaf water with different kinetic fractionation coefficients].

Clarifying O isotope composition of leaf water (δ) would provide theoretical refe-rence for the study of leaf physiology and forest hydrology. We continuously monitored the concentration of atmospheric water vapor (W) and O isotope composition of atmospheric water vapor (δ) at the canopy of Platycladus lateralis plantation in the mountain area of Beijing. We analyzed the effects of kinetic fractionation coefficients Δ(32%) and Δ(28%) on the prediction of δ by combining the measured leaf water O isotope (δ) and δ of P.

[Assessing water sources for Populus simonii with different degrees of degradation based on stable isotopes].

Water availability is the key factor limiting plant growth in arid regions. Populus simonii is a typical shelterbelt tree species in Zhangbei County, Hebei Province, with an important role in constructing ecological barrier. With stable isotope technique, graphical method, and multiple linear mixing model, we analyzed water sources and water use strategies of P.

[Effects of soil water stress and atmospheric CO concentration on photosynthetic and post-photosynthetic fractionation].

Analysis of plant photosynthesis and post-photosynthetic fractionation can improve our understanding of plant physiology and water management. By measuring δC in the atmosphere, and δC of soluble compounds in leaves and branch phloem of Platycladus orientalis, we examined discrimination pattern, including atmosphere-leaf discrimination during photosynthesis (ΔC) and leaf-twig discrimination during post-photosynthesis (ΔC), in response to changes of soil water content (SWC) and atmospheric CO concentration (C). The results showed that ΔC reached a maximum of 13.

Environmental and physiological controls on diurnal and seasonal patterns of biogenic volatile organic compound emissions from five dominant woody species under field conditions.

Biogenic volatile organic compounds (BVOCs) play essential roles in tropospheric chemistry, on both regional and global scales. The emissions of large quantities of species-specific BVOC depend not only on environmental (temperature, T; photosynthetically active radiation, PAR), but also physiological parameters (i.e.

Effects of Simulated Gravel on Hydraulic Characteristics of Overland Flow Under Varying Flow Discharges, Slope Gradients and Gravel Coverage Degrees.

To quantify the hydraulic characteristics of overland flow on gravel-covered slopes, eight flow discharges (Q) (8.44-122 L/min), five slope gradients (J) (2°-10°) and four gravel coverage degrees (Cr) (0-30%) were examined via a laboratory flume. The results showed that (1) gravel changed flow regime.

Size distribution of particulate matter in runoff from different leaf surfaces during controlled rainfall processes.

The presence of plant leaves has been shown to lower the risks of health problems by reducing atmospheric particulate matter (PM). Leaf PM accumulation capacity will saturate in the absence of runoff. Rainfall is an effective way for PM to "wash off" into the soil and renew leaf PM accumulation.

Scale effects on runoff and a decomposition analysis of the main driving factors in Haihe Basin mountainous area.

Catchment runoff scale relationships comprise an important theoretical support for water resource management. However, previous understandings of the scale effect were mostly based on empirical summaries and quantitative research, while interpretation based on measured data was rare. The purpose of this paper was to quantitatively reveal the causes of runoff scale impacts in the Haihe mountainous area over a 20-year period.

Particulate matter transported from urban greening plants during precipitation events in Beijing, China.

Particulate matter (PM) deposited on canopy surfaces could be washed off and carried in throughfall to the ground. This would help plants recapture airborne PM on their canopy surfaces and then develop a PM purification capacity. Sixteen commonly greening plant species in north China (including 13 arbor species and 3 shrub species) were selected to investigate the washing process of plant-deposited PM during precipitation events.

Biological denitrification using polycaprolactone-peanut shell as slow-release carbon source treating drainage of municipal WWTP.

The development of slow-release carbon source is an effective way to reduce the total nitrogen (TN) in low carbon to nitrogen ratio wastewater. In this study, a novel solid slow-release carbon source (PPP) was prepared using polycaprolactone (PCL) and peanut shell (PS) as carbon sources with polyvinyl alcohol-sodium alginate (PVA-SA) as hybrid scaffolds. The carbon release properties of PPP and each carbon source materials were compared.

Influence of physiological and environmental factors on the diurnal variation in emissions of biogenic volatile compounds from Pinus tabuliformis.

Biological volatile organic compounds (BVOCs) have a large influence on atmospheric environmental quality, climate change and the carbon cycle. This study assesses the composition and diurnal variation in emission rates of BVOCs from Pinus tabuliformis, using an enclosure technique. Environmental parameters (temperature and light intensity) and physiological parameters (net photosynthetic rate, P; stomatal conductance, g; intercellular CO concentration, C; and transpiration rate, T) that may affect emission behavior were continuously monitored.