| 1. |
- Liu, Linan, et al.
(author)
-
Silicon Effects on Biomass Carbon and Phytolith-Occluded Carbon in Grasslands Under High-Salinity Conditions
- 2020
-
In: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 11, s. 1-13
-
Journal article (peer-reviewed)abstract
- Changes in climate and land use are causing grasslands to suffer increasingly fromabiotic stresses, including soil salinization. Silicon (Si) amendment has been frequentlyproposed to improve plant resistance to multiple biotic and abiotic stresses and increaseecosystem productivity while controlling the biogeochemical carbon (C) cycle. However,the effects of Si on plant C distribution and accumulation in salt-suffering grasslandsare still unclear. In this study, we investigated how salt ions affected major elementalcomposition in plants and whether Si enhanced biomass C accumulation in grasslandspecies in situ. In samples from the margins of salt lakes, our results showed that thediffering distance away from the shore resulted in distinctive phytocoenosis, includinghalophytes and moderately salt-tolerant grasses, which are closely related to changingsoil properties. Different salinity (NaC/KC, ranging from 0.02 to 11.8) in plants causednegative effects on plant C content that decreased from 53.9 to 29.2% with theincrease in salinity. Plant Si storage [0.02–2.29 g Si m?2 dry weight (dw)] and plantSi content (0.53 to 2.58%) were positively correlated with bioavailable Si in soils(ranging from 94.4 to 192 mg kg?1). Although C contents in plants and phytoliths werenegatively correlated with plant Si content, biomass C accumulation (1.90–83.5 g Cm?2 dw) increased due to the increase of Si storage in plants. Plant phytolith-occludedcarbon (PhytOC) increased from 0.07 to 0.28h of dry mass with the increase of Sicontent in moderately salt-tolerant grasses. This study demonstrates the potential ofSi in mediating plant salinity and C assimilation, providing a reference for potentialmanipulation of long-term C sequestration via PhytOC production and biomass Caccumulation in Si-accumulator dominated grasslands.
|
|
| 2. |
- Zheng, Xiaodi, et al.
(author)
-
Extreme Copper Isotope Fractionation Driven by Redox Oscillation During Gleysols Weathering in Mun River Basin, Northeast Thailand
- 2023
-
In: Journal of Geophysical Research - Earth Surface. - : John Wiley & Sons. - 2169-9003 .- 2169-9011. ; 128:3
-
Journal article (peer-reviewed)abstract
- The fractionation of copper (Cu) isotope is a process related to the redox fluctuation during soil Cu biogeochemical cycling. For Cu isotope composition in weathered gleysols of tropical zones, the increased rates of redox fluctuations are assumed to occur during gleysol evolution due to the seasonal exchange of groundwater and river water. However, the impact of the frequency of redox fluctuations on soil Cu isotope signatures is rarely documented. Here, we analyzed the variations of Cu content and isotope fractionation in two low-humic gleysol profiles with different pedogenetic processes during weathering in the same basin (Mun River Basin), and found that the frequency of redox fluctuations could determine the magnitude of Cu isotope fractionation. We record an increased light Cu isotopes and identify the stable Cu(I) species retained in the residual soils with the increased frequency of redox fluctuation. Several processes contribute to Cu isotope fractionation at different soil horizons, but most isotope fractionation is related to the re-adsorption or re-precipitation by iron and manganese oxyhydroxide (i.e., ferrihydrite and pyrolusite), especially at the iron or manganese-rich zone. Cu isotope fractionation is sensitive to increased redox fluctuations in the terrestrial ecosystem, and may have significant implications for assessing soil ecological vulnerability under future climate change scenarios.
|
|
| 3. |
- Treydte, Kerstin, et al.
(author)
-
Recent human-induced atmospheric drying across Europe unprecedented in the last 400 years
- 2024
-
In: NATURE GEOSCIENCE. - 1752-0894 .- 1752-0908. ; 17, s. 58-65
-
Journal article (peer-reviewed)abstract
- The vapor pressure deficit reflects the difference between how much moisture the atmosphere could and actually does hold, a factor that fundamentally affects evapotranspiration, ecosystem functioning, and vegetation carbon uptake. Its spatial variability and long-term trends under natural versus human-influenced climate are poorly known despite being essential for predicting future effects on natural ecosystems and human societies such as crop yield, wildfires, and health. Here we combine regionally distinct reconstructions of pre-industrial summer vapor pressure deficit variability from Europe's largest oxygen-isotope network of tree-ring cellulose with observational records and Earth system model simulations with and without human forcing included. We demonstrate that an intensification of atmospheric drying during the recent decades across different European target regions is unprecedented in a pre-industrial context and that it is attributed to human influence with more than 98% probability. The magnitude of this trend is largest in Western and Central Europe, the Alps and Pyrenees region, and the smallest in southern Fennoscandia. In view of the extreme drought and compound events of the recent years, further atmospheric drying poses an enhanced risk to vegetation, specifically in the densely populated areas of the European temperate lowlands. The atmosphere has dried across most regions of Europe in recent decades, a trend that can be attributed primarily to human impacts, according to tree ring records spanning 400 years and Earth system model simulations.
|
|
