Deciphering dust outbreak frequency in inland Asia during the late Cenozoic is important for predicting future hydroclimate in the arid parts of China. Here, we present an eolian sedimentary sequence ...in the southern Junggar Basin over the past 3.5 Ma, Northwestern China. Our data provide a minimum age of 3.5 Ma for the Gurbantunggut Desert. Rb/Sr ratios exhibit prominent 405 Kyr eccentricity cycles throughout our record with weak expression 41 Kyr cycles. We interpret this cyclicity as resulting from a strong impact of the global carbon cycle on western China hydroclimate. By contrast, gamma‐ray intensity data displays significant 100‐ and 41‐Kyr cycles after 2.8 Ma, suggesting important variations of the input of westerly derived dust. Our results demonstrate that Westerly derived moisture supply and dust input into inland Asia respond differently to orbital forcing; they suggest that moisture supply and dust transport by the Westerlies are controlled by different drivers since 3.5 Ma.
Plain Language Summary
Little is known about how hydrological changes in desert areas respond to today’s high atmospheric CO2 concentrations. Hydroclimatic archives from these areas are critical to understand (and possibly forecast) future hydrological changes at local and regional scales. Herein, we present paleomagnetic, gamma‐ray intensity and Rb/Sr data over the past 3.5 Ma from an eolian sedimentary sequence in the southern Junggar Basin, Northwestern China. Our results provide a minimum age of 3.5 Ma for the Gurbantunggut Desert; they show that humidity and Westerlies strength variations in inland Asia follow different cyclicity during the Quaternary, indicating that moisture supply by the Westerlies since 3.5 Ma is not directly impacted by wind strength. Our results show that Junggar hydroclimate is likely poorly sensitive to changes in Westerlies strength, despite their role as moisture conveyor, raising questions about the main control on moisture supply in inland Asia.
Key Points
Rb/Sr ratios exhibit prominent 405 Kyr eccentricity cycles throughout our record
GR data displays significant 100‐ and 41‐Kyr cycles after 2.8 Ma
Moisture supply by westerlies is not directly impacted by wind strength since at least 3.5 Ma
The perception mechanism for the strigolactone (SL) class of plant hormones has been a subject of debate because their receptor, DWARF14 (D14), is an α/β-hydrolase that can cleave SLs. Here we show ...via time-course analyses of SL binding and hydrolysis by Arabidopsis thaliana D14, that the level of uncleaved SL strongly correlates with the induction of the active signaling state. In addition, we show that an AtD14
catalytic mutant that lacks enzymatic activity is still able to complement the atd14 mutant phenotype in an SL-dependent manner. We conclude that the intact SL molecules trigger the D14 active signaling state, and we also describe that D14 deactivates bioactive SLs by the hydrolytic degradation after signal transmission. Together, these results reveal that D14 is a dual-functional receptor, responsible for both the perception and deactivation of bioactive SLs.
The opening and closure of marine gateways have been suggested to substantially affect ocean current circulations and global climatic changes. In the Miocene, the closure of the Tethyan Seaway, which ...connected the proto-Mediterranean Sea with the Indian and Atlantic Oceans, blocked thermohaline exchanges between them and possibly caused a major climate change in the Middle Miocene Climatic Transition. However, the timing, process, and forcing mechanism of the closure of this seaway are controversial. To address this question, we focus on the chronology and sedimentary facies of Miocene strata in the Zagros foreland basin in the Western Iranian Plateau. Based on magnetostratigraphy and biostratigraphy, we establish a chronology of 17 to 10 Ma for the studied Miocene strata and constrain the timing of the permanent closure of the northwestern segment of the Tethyan Seaway to 12.8 Ma. By comparison with global sea-level fluctuations, we suggest that middle Miocene marine transgressions and regressions in the studied region were mainly driven by global climatic change through its control on the growth and decay of ice sheets and thus sea level changes. Our detailed depositional sequence analysis exhibits 100-kyr Earth's eccentricity cycles of marine transgressions and regressions between 15.0 and 12.8 Ma implying they were controlled by astronomical factors. Moreover, the Tethyan Seaway experienced stepwise evolution changing from partially opened seaway, restricted marine connection, intermittent connections, to permanent closure in its northwestern segment during the early and middle Miocene.
•New chronology of the Cenozoic marine-terrestrial strata in the Zagros foreland.•Permanent closure of the northwestern segment of the Tethyan Seaway at ca. 12.8 Ma.•Marine transgressions/regressions were driven by global sea-level fluctuations.•100-kyr cycles of marine transgressions/regressions were recorded.•The Tethyan Seaway experienced stepwise evolution from early to middle Miocene.
Understanding the relationship between glacier meltwater and lake water temperature changes on the Tibetan Plateau (TP) is important for water resources management, environmental protection, and ...geological risk analysis. Summer temperature is one of the main factors affecting glacier evolution, yet we lack summer temperature records for high-altitude regions where glaciers are widely developed. In this study, we established a calibration between TEX86, which measures the abundance of aquatic isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) of Group I.1a aquatic Thaumarchaeota, and mean annual lake water temperature (MLWT) for 17 surface sediment samples from 10 lakes on the TP (MLWT = 4.1× TEX86 + 2.6 °C, R2 = 0.77). Given that lakes freeze during the cold season, MLWT is a record of the warm season temperature, especially the summer-biased temperature. We applied this calibration to reconstruct a Holocene MLWT record for Bangdag Co, a high-altitude hydrologically-closed lake (4909 m a.s.l.) on the northwestern TP, where glaciers are widely developed. The record shows low temperatures during the early Holocene, high temperatures during the middle Holocene, and a cooling trend during the middle to late Holocene. The MLWT is negatively correlated with the glacial meltwater volume during the early Holocene, indicating a large glacial meltwater influx to the lake at this time which resulted in low lake-water temperatures. Following the decrease in summer insolation during the middle to late Holocene, summer temperatures decreased and thus glacier meltwater production decreased. The MLWT shows a significant positive correlation with the glacial meltwater volume during the middle to late Holocene, which indicates that glacier meltwater barely influenced the MLWT, which was mainly controlled by the summer air temperature. Overall, when the air temperature decreased, the MLWT was low and the glacier meltwater production decreased. Our MLWT record for Bangdag Co agrees well with the cooling trend evident in summer temperature records and model simulations for the TP during the middle to late Holocene, which can be primarily attributed to decreasing summer insolation.
•A calibration between the TEX86 and annual mean lake water temperature have been constructed on the Tibetan Plateau.•The Holocene water temperature variation from a high-altitude closed lake is quantitatively estimated on the northwestern Tibetan Plateau.•Lake water temperature is influenced by meltwater input during the early Holocene and controlled by summer air temperature during the mid-late Holocene.
The timing of tectonic deformation in the Zagros foreland basin provides important information about the tectonic propagation process driven by the Arabia‐Eurasia convergence. The chronology of ...growth strata is one of the most important methods to delimit the history of folding and thrusting within the foreland basin. In this study, we report integrated analyses of sedimentology, magnetostratigraphy, and biostratigraphy of Miocene strata in the Dezful Embayment in the SW Zagros foreland basin. The new results indicate that deposition of the northern limb of the Gach‐e Moh Anticline was between 14.6 and 8.6 Ma; that includes the Upper Gachsaran Formation (14.6–13.8 Ma), the Mishan Formation (13.8–12.8 Ma), and the Agha Jari Formation (12.8–8.6 Ma). Based on magnetostratigraphic and sedimentary evidence, the transition from marine to non‐marine was at ∼12.8 Ma. Analysis of temporal lithofacies‐stacked patterns shows there were seventeen transgression‐regression cycles during the Middle Miocene Climatic Transition with a ∼100‐Kyr Earth eccentricity cycle, suggesting that the cyclic marine transgressions and regressions were mainly driven by eustatic sea level fluctuations; but tectonic‐induced basin subsidence also contributed marine transgressions in the Upper Mishan Formation. The final seawater retreat was at 12.8 Ma driven by both the global eustatic sea level drop and the enhanced south‐westward progradation of sediments eroded from the High Zagros. The base of the growth strata in the footwall of the Mountain Front Fault was at ∼11 Ma, suggesting that tectonic deformation caused by the Arabia‐Eurasia collision had propagated to the Dezful Embayment by that time.
Key Points
Magnetostratigraphic chronology in the Dezful Embayment yields an age range of ∼15–9 Ma in the Zagros foreland
Tectonic deformation propagated to the Dezful Embayment at 11 Ma driven by the onset of thrusting from the Mountain Front Fault
Final seawater retreat in the Dezful Embayment was at 12.8 Ma, and the marine transgressions/regressions had a quasi‐cycle of 100‐Kyr
•Accurately estimate annual lake water storage using optical and altimetry satellites;•Hulun Lake rapidly rebounded (0.65 km3/yr) since 2012 after continuous decline;•Increasing river water supply ...greatly contributed to lake water storage rebound;•Reveal the considerable impact of surface water changes on regional water storage;
The widely distributed surface water bodies (e.g., lakes and reservoirs) are important components of water resources on Earth, their spatial–temporal dynamics can pose significant effects on regional water resources. Previous studies generally attributed variability in terrestrial water storage (TWS) to groundwater dynamics, hardly considering surface water changes, making the influence of the changing surface water storage on TWS unclear. Here, by taking Hulun Lake as an example, which occupies 94.0 % of the total water areas in the target basin, we quantitatively revealed the impacts of changes in lake water volume on TWS. Using cloud computing-based water body monitoring and altimetry satellite-based water level measurements, we found continuous lake shrinkage (25 km2/yr) before 2012 while rapid expansion after that. By coupling water areas with levels, annual lake volumes were estimated. We showed that lake volumes also significantly declined (−0.52 km3/yr) before 2012, and then rapidly restored (0.65 km3/yr) due to the increasing water recharge from rivers. The increasing rate of lake water volume was higher than that of TWS (0.15 km3/yr), indicating the great contribution of lake volume increases to TWS gains. Our study highlights the considerable impacts of the changing surface water bodies on regional water resources and it is essential to consider storage changes in surface water when attributing the drivers of TWS variability in regions experiencing dramatic lake changes. Our method proposed is also applicable to evaluating the impacts of surface water changes on TWS in other similar areas around the world.
Stable carbon isotopes of long-chain
n
-alkanes in lake sediments have been used for reconstructing past environmental changes. Gas chromatography isotope ratio mass spectrometry coupled to a ...combustion unit is the commonly applied technique for compound-specific carbon isotope analysis. This paper shows that sulfur in the lacustrine sediment can cause severe interference during the mass spectrometric measurement, leading to significant biases in δ
13
C of
n
-alkane. The δ
13
C deviation could be resulted from additional
12
C
33
S
+
,
13
C
32
S
+
at mass-to-charge ratio (
m/z
) 45, and
12
C
34
S
+
, H
2
C
32
S
+
at
m/z
46, respectively. Such elemental sulphur interference can be eliminated by the activated copper in the pretreatment procedure.
The aeolian deposits in the coastal region of North China are important for reconstructing paleoclimate. In this paper, chronology, climatic proxies and chemical compositions of four loess sections ...were studied. Optically stimulated luminescence (OSL) dating results indicate that the coastal loess was accumulated during late Quaternary, with ages ranging from the penultimate glacial period to the latest Holocene. Both granulometric characteristics and geochemical properties indicate that the dust provenance of the coastal loess is partially different from that of the Chinese Loess Plateau, characterized by more proximal contributions. Except distal dust transported by northwesterly winter winds from the inland gobi and sand deserts, the coastal loess also contains proximal, local coarse particles, which were derived from the exposed shelf as well as neighboring hills. Multiple climatic proxies, including color, magnetic susceptibility and particle size parameters, correlate well with the marine SPECMAP δ18O record, indicating that climatic changes in the coastal region of North China during the late Quaternary was mainly controlled by variations of the East Asian monsoon, driven by changes in global ice volumes.
•Luminescence dating of coastal loess in eastern North China.•Coastal loess contain both distal and proximal source materials.•Exposed shelf during glacial time serving as an important source for coastal loess.•Costal loess reflects orbital climatic fluctuations driven by East Asian monsoon.
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•A new index was proposed to evaluate the influence of ENSO on all tropical vegetation better.•The tropics showed a greening trend from 1982 to 2018.•ENSO event can lead to the ...greening or browning in at least 10% of tropical areas.•The increasing of precipitation and temperature played the leading role in the process of greening and browning respectively.•The VERI in different periods showed the interesting changes of ENSO's influence on vegetation.
With the intensification of extreme weather events in recent years, the drought, flood and fire caused by super El Niño - Southern Oscillation (ENSO) led to lot’s of vegetation destruction in multiple tropical regions. However, little is known about the influence of ENSO on tropical vegetation of long time series (especially after 2015) and the influence’s internal mechanism. Based on generating the long-term vegetation data (combined multiple satellite sensors data), a new index (Vegetation - ENSO response index, VERI) was created to evaluate the influence of ENSO on vegetation more accurately and comprehensively, which considering several factors including the correlation between ENSO index and NDVI anomaly, the change amplitude of NDVI in ENSO events and the duration time and lag time of the influence of ENSO on vegetation. The analysis indicated that tropical vegetation exhibited a fluctuating increase state with an overall increasing range of 4.46%, and the greening trends were the most significant and dramatical in the Indian Peninsula (0.0031/y), the coast of the Gulf of Guinea (0.0026/y), and the Amazon River estuary (0.0025/y). ENSO can lead to significant enhancement or degradation of vegetation in at least 10% of tropical regions, especially in East Africa (|VERI| =0.16), Southern Africa (|VERI|=0.18) and Indonesia (|VERI|=0.14). Among them, shrubs are the most widely affected areas (32.08%) due to limited water resources. ENSO's greening effect is mainly accomplished by increasing precipitation (warm/r = 0.166, cold/r = 0.249) and its degradation effect is more closely related to temperature increase (warm/r = −0.374, cold/r = −0.101). The change of VERI in different periods indicated that the ENSO's influence on vegetation has changed after 2000, which meant the improving effect of cold events on tropical vegetation was weakened, while the inhibiting effect was enhanced. These findings can help us better understand and respond to the effects of ENSO on tropical vegetation in the context of global change.
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•High-loaded curcumin nanosuspensions were prepared with the media grinding method.•Curcumin nanosuspensions could be used as emulsifiers to prepare stable emulsions.•Emulsions ...stabilized by nanosuspensions retarded the oxidation of algae oil.•The content of curcumin micelle increased with the increase of nanosuspensions.
Currently, curcumin still faces issues like low loading capacity and poor absorption performance, limiting its applications in antioxidant performance. Emulsions stabilized with high-load curcumin/octenyl succinic anhydride (OSA) starch nanosuspensions, aiming to enhance the antioxidant activity of algal oil and improve curcumin absorption.
The physicochemical properties of emulsions stabilized by curcumin nanosuspensions, the oxidative characteristics of algae oil, and the absorption performance of curcumin were investigated. The crystalline content of curcumin was notably decreased by the media grinding process. Furthermore, the emulsions prepared from nanosuspensions with different curcumin contents exhibited good thermal and centrifugal stability. Importantly, as the curcumin concentration in the emulsions increased, the curcumin content in the micelles also increased, leading to a gradual decrease in the oxidation degree of algal oil. These research findings provide a theoretical basis for the development of curcumin high-loaded nanosuspension emulsion systems and their wide application in the food industry.
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