Why does afforestation policy lead to a drying trend in soil moisture on the Loess Plateau?

Soil moisture is a key factor for vegetation restoration in arid and semi-arid regions. Clarifying the vertical characteristics of soil moisture in artificial forests on a regional scale and its response mechanisms can benefit for land use management in water-deficient areas such as the Loess Plateau. The study targets Robinia pseudoacacia on the Loess Plateau with a meta-analysis based on 790 soil moisture data points abstracted from 35 published papers. The results show that extensive cultivation of R pseudoacacia on the Loess Plateau leads to a significant reduction in soil moisture (P < 0.05). Soil moisture decreases significantly with growth of trees, especially between 400 and 500 cm soil layers. Soil moisture increases with the hydrothermal gradient. The results indicate that intensive afforestation activities in high temperature and rainy areas still significantly consume deep soil moisture. The main reason is that the impact of hydrothermal factors on soil moisture is significant between 0 and 200 cm soil layers and decreases with increasing soil depth. However, the continuous depletion of deep soil moisture leads to insignificant differences in soil moisture responses under different topographical conditions in the region. Therefore, neglecting the impact of forest age and hydrothermal factors on soil moisture in afforestation activities, the excessive water consumption by R pseudoacacia during growth poses potential risks to the ecological environment of the Loess Plateau. This study provides references for knowledge on water relating problems and sustainable management of artificial forests in arid and semi-arid areas.

Amphibians rise to flourishing under climate change on the Qinghai-Tibetan Plateau.

Amphibian populations are declining globally due to climate change. However, the impacts on the geographic distribution of amphibians on the Qinghai-Tibetan Plateau (QTP), a global biodiversity hotspot with 112 species of amphibians that is sensitive to global climate change, remains unclear. In this study, MaxEnt and barycentre shift analyses were performed to reveal the impact of climate change on the potential future habitats of amphibians on the QTP using the BCC-CSM2-MR global climate model of the Coupled Model Intercomparison Projects Phase 6 (CMIP6) climate pattern with three shared socioeconomic pathways (SSP). In contrast to the widespread decline in the amphibian population, the future scenarios projected an increase in most amphibian habitats on the QTP, accompanied by migration to higher elevations or latitudes under three climatic projections (SSP 1-2.6, 3-7.0, and 5-8.5). Average annual precipitation was the most crucial environmental variable impacting the future distribution of amphibians. The findings indicate that amphibians would flourish under climate change on the QTP, which is of great significance for the protection of amphibians and biodiversity on the QTP.

Integrative proteome and metabolome analyses reveal molecular basis of the tail resorption during the metamorphic climax of Nanorana pleskei.

During the metamorphosis of anuran amphibians, the tail resorption process is a necessary and crucial change. One subject that has received relatively little or no attention is the expression patterns of proteins and metabolites in the different tail portions during metamorphosis, especially in highland amphibians. The mechanisms of tail resorption in three portions (the tip, middle and root) of the tail were investigated in N. pleskei G43 tadpole based on two omics (proteomic and metabolomic). Integrin αVß3 was found to be high expressed in the distal portion of the tail, which could improve the sensitiveness to thyroid hormones in the distal portion of the tail. Muscle regression displayed a spatial pattern with stronger regression in distal and weaker one in proximal portion. Probably, this stronger regression was mainly performed by the proteases of proteasome from the active translation by ribosomes. The suicide model and murder model coexisted in the tail resorption. Meanwhile, fatty acids, amino acids, pyrimidine, and purine which derived from the breakdown of tissues can be used as building blocks or energy source for successful metamorphosis. Our data improved a better comprehension of the tail resorption mechanisms underlying the metamorphism of N. pleskei tadpole through identifying important participating proteins and metabolites.

Response of alpine vegetation function to climate change in the Tibetan Plateau: A perspective from solar-induced chlorophyll fluorescence.

Vegetation change on the Tibetan Plateau (TP) is a crucial indicator of climate change in alpine regions. Previous studies have reported an overall greening trend in the vegetation structure across the TP, especially in its northeastern part, in response to a warming climate. However, variations in the vegetation function and the possible drivers remain poorly understood. Considering the optimal temperature for plants in TP is usually higher than the current temperature, our hypothesis is the function and structure of alpine vegetation have changed synchronously over past few decades. To test this hypothesis, we analyzed satellite-observed solar-induced chlorophyll fluorescence (SIF) and leaf area index (LAI) in the Yellow River source (YRS) region in the northeastern TP to quantify the long-term trends in vegetation functional and structural states, respectively. The results suggest that from 1982 to 2018, SIF increased significantly in 77.71 % of the YRS area, resulting in a significant upward trend of 0.52 × 10-3 mW m-2 nm-1 sr-1 yr-1 (p < 0.001) for the regional-mean SIF. This represents a 16.1 % increase in SIF, which is close in magnitude to the increase in LAI over the same period. The synchronous changes between vegetation function and structure suggest that improved greenness corresponds to a similar level of change in carbon uptake across YRS. Additionally, we used a multiple regression approach to quantify the contribution of climatic factors to SIF changes in YRS. Our analyses show that the increases in SIF were primarily driven by rising temperatures. Spatially, temperature dominated SIF changes in most parts of YRS, except for certain dry parts in the northern and western YRS, where precipitation had a greater impact. Our results are crucial for a comprehensive understanding of climate regulations on vegetation structure and function in high-elevation regions.

Dissolved trace elements in the upper reaches of Lancang River, southeast Qinghai-Tibet Plateau: Current status and distribution, risk and source.

The environmental impact of dissolved trace element (DTE) pollution is becoming increasingly well understood. The southeastern edge of the Qinghai-Tibet Plateau is a region with high environmental vulnerability, making it highly susceptible to various anthropogenic disturbances. The Lancang River (LCR), as the most representative river in this area, serving as the largest international river in Southeast Asia, the LCR is crucial for the downstream regions, supporting fisheries, agriculture, and even economic development, earning it the title of the "water tower" for these areas. This study mainly focuses on the upstream unbuilt dam area. In this study, we gathered 25 surface water samples from the upstream of the LCR and examined the geographical distribution, primary sources, and associated human health risks of seven dissolved trace elements (Mn, Cr, Fe, Co, Cu, Ni, Zn). Cr, Fe, Co, Ni, and Cu in the main stream are primarily associated with natural sources, including rock weathering, soil erosion, and similar processes. Mn, however, predominantly originates from human activities such as industrial construction and road transportation. Zn mainly originates from the specialized fertilizers used for highland barley in plateau regions. Almost all DTE concentrations exhibited a downward trend from upstream to downstream. However, due to inputs from various sources along the way, there will be some abnormal points. The concentrations of DTE in the study area were within the acceptable limits set by drinking water standards in China, the USA, and the WHO. Overall, the water quality in this region is considered good. The results from a Monte Carlo simulation assessing health risks indicate that the non-carcinogenic health risk caused by DTE in the upper reaches of Lancang River was very weak. The primary pathway through which DTE can harm human health is ingestion, with children being particularly vulnerable. These findings offer a critical scientific basis for understanding the migration of DTE in aquatic environments and for the ecological stewardship of the Lancang River.

Exploring soil nitrogen and sulfur dynamics: implications for greenhouse gas emissions on the Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau is particularly vulnerable to the effects of climate change and disturbances caused by human activity. To better understand the interactions between soil nitrogen and sulfur cycles and human activities on the plateau, the distribution characteristics of soil nitrogen and sulfur density and their influencing factors for three soil layers in Machin County at depths of 0-20 cm, 0-100 cm, and 0-180 cm are discussed in this paper. The results indicated that at depths of 0-180 cm, soil nitrogen density in Machin County varied between 1.36 and 16.85 kg/m2, while sulfur density ranged from 0.37 to 4.61 kg/m2. The effects of three factors-geological background, land use status, and soil type-on soil nitrogen and sulfur density were all highly significant (p < 0.01). Specifically, natural factors such as soil type and geological background, along with anthropogenic factors including land use practices and grazing intensity, were identified as decisive in causing spatial variations in soil nitrogen and sulfur density. Machin County on the Tibetan Plateau exhibits natural nitrogen and sulfur sinks; However, it is crucial to monitor the emissions of N2O and SO2 into the atmosphere from areas with high external nitrogen and sulfur inputs and low fertility retention capacities, such as bare land. On this basis, changes in the spatial and temporal scales of the nitrogen and sulfur cycles in soils and their source-sink relationships remain the focus of future research.

Investigating the environmental capacity of soil heavy metals and its determinants in agro-pastoral regions of the qinghai-tibetan plateau.

Environmental capacity (EC) serves as the basis for environmental planning and management, as a key indicator for assessing environmental risk and quality, and as a foundation for achieving sustainable development. Studies on EC typically address agricultural or urban rather than pastoral areas, with few examining agro-pastoral areas. The EC of the Tibetan Plateau is particularly important, considering its importance as an agricultural area and ecological reserve. To address this gap, the Qingshizui area in Menyuan County, a typical agro-pastoral area on the Tibetan Plateau, was selected to quantify soil EC and its spatial distribution. In terms of the dynamic and static annual soil EC for this region, the heavy metals were ranked as follows, in ascending order: Cd, Hg, Co, As, Sb, Ni, Cu, Pb, Cr, and Zn. Most of the areas with high residual EC were in the west. For the 10 heavy metals, residual EC was significantly affected by geological background. For all the heavy metals except Zn and Hg, residual EC was significantly affected by soil type. The heavy metal elements in the agro-pastoral area's soil are mildly enriched, suggesting minimal human impact. The composite EC index of this soil is 0.98, indicating an intermediate EC and low health risk. This study underscores that integrating agriculture and pastoralism can optimize land use and mitigate ecological pressures associated with these practices when done separately. Our research provides valuable insights for resource optimization, environmental conservation, and enhancing the welfare of farmers and herders in the Qinghai-Tibet region.

Tibetan lake change linked to large-scale atmospheric oscillations via hydroclimatic trajectory.

Lakes are known as sentinels of climate change, but their responses may differ from one to another leading to different strategies in lake protection. It is particularly the case in the Tibetan Plateau (TP) of multiple hydrological processes. We employed the Budyko framework to study Tibetan lakes from two lake-basins of contrasting climates for the period between 1980 and 2022: Taro Co Basin (TCB) in a sub-arid climate, and Ranwu Lake Basin (RLB) in a sub-humid climate. Our results showed that total lake area, surface air temperature, evapotranspiration, and potential evapotranspiration increased in both lake-basins, while precipitation and soil moisture increased in the TCB but decreased in the RLB. In the Budyko space, two basins had contrast hydroclimatic trajectories in terms of aridity and evaporative index. The TCB shifted from wetting to drying trend, while the RLB from drying to wetting in early 2000s. Notably, lake change was generally consistent with the drying/wetting phases in the TCB, but in contrast with that in the RLB, which can be attributed to warming-induced glacier melting. Despite of significant correlation with the large-scale atmospheric oscillations, it turned to be more plausible if lake area changes were substituted with basin's hydroclimatic trajectories. Among the large-scale oscillations, El Niño-Southern Oscillation (ENSO) is the most dominant control of lake trends and their drying/wetting shifts. Our findings offer a valuable insight into lake responses to climate change in the TP and other regions.

The last of their kind: Is the genus Scutiger (Anura: Megophryidae) a relict element of the paleo-transhimalaya biota?

The orographic evolution of the Himalaya-Tibet Mountain system continues to be a subject of controversy, leading to considerable uncertainty regarding the environment and surface elevation of the Tibetan Plateau during the Cenozoic era. As many geoscientific (but not paleontological) studies suggest, elevations close to modern heights exist in vast areas of Tibet since at least the late Paleogene, implicating the presence of large-scale alpine environments for more than 30 million years. To explore a recently proposed alternative model that assumes a warm temperate environment across paleo-Tibet, we carried out a phylogeographic survey using genomic analyses of samples covering the range of endemic lazy toads (Scutiger) across the Himalaya-Tibet orogen. We identified two main clades, with several, geographically distinct subclades. The long temporal gap between the stem and crown age of Scutiger may suggest high extinction rates. Diversification within the crown group, depending on the calibration, occurred either from the Mid-Miocene or Late-Miocene and continued until the Holocene. The present-day Himalayan Scutiger fauna could have evolved from lineages that existed on the southern edges of the paleo-Tibetan area (the Transhimalaya = Gangdese Shan), while extant species living on the eastern edge of the Plateau originated probably from the eastern edges of northern parts of the ancestral Tibetan area (Hoh Xil, Tanggula Shan). Based on the Mid-Miocene divergence time estimation and ancestral area reconstruction, we propose that uplift-associated aridification of a warm temperate Miocene-Tibet, coupled with high extirpation rates of ancestral populations, and species range shifts along drainage systems and epigenetic transverse valleys of the rising mountains, is a plausible scenario explaining the phylogenetic structure of Scutiger. This hypothesis aligns with the fossil record but conflicts with geoscientific concepts of high elevated Tibetan Plateau since the late Paleogene. Considering a Late-Miocene/Pliocene divergence time, an alternative scenario of dispersal from SE Asia into the East, Central, and West Himalaya cannot be excluded, although essential evolutionary and biogeographic aspects remain unresolved within this model.

The changing permafrost environment under desertification and the heat transfer mechanism in the Qinghai-Tibetan Plateau.

With the development of desertification in the Qinghai-Tibet Plateau (QTP), aeolian sand becomes the remarkable local factor affecting the thermal state of permafrost along the Qinghai-Tibet Engineering Corridor (QTEC). In this study, a model experiment was conducted to analyze the impact of thickness and water content of aeolian sand on its thermal effect, and a hydro-thermo-vapor coupling model of frozen soil was carried out to reveal the heat transfer mechanism of the aeolian sand layer (ASL) with different thicknesses and its hydrothermal effect on permafrost. The results indicate that: (1) ASL with the thickness larger than 80 cm has the property of converting precipitation into soil water. The thicker the ASL, the more precipitation infiltrates and accumulates in the soil layer. (2) The cooling effect of ASL on permafrost results from the lower net surface radiation, causing the annual average surface heat flux shifting from heat inflow to heat outflow. The warming effect of ASL on permafrost results from the increasing convective heat accompanying the infiltrated precipitation. (3) As the ASL thickens, the thermal effect of ASL on permafrost gradually shifts from the cooling effect dominated by heat radiation and heat conduction to the warming effect dominated by precipitation infiltration and heat convection. The warming effect of thick ASL on permafrost requires a certain amount of years to manifest, and the critical thickness is suggested to be larger than 120 cm.

Outpatient surgery for tibial plateau fractures.

PURPOSE: The purpose of this study was to determine the rates of compartment syndrome and other early complications following outpatient open reduction and internal fixation (ORIF) of tibial plateau fractures. METHODS: This was a retrospective cohort at a single US level I academic trauma centre of patients with tibial plateau fractures managed operatively. Inpatients received their definitive ORIF during their index hospital stay and were admitted post-operatively following ORIF. Outpatients were scheduled for ambulatory surgery during definitive ORIF. Exclusion criteria for outpatient surgery included compartment syndrome, polytrauma, open types IIIb/IIIc, and patients who received any internal fixation during index presentation. The primary outcome measure was post-operative compartment syndrome. Secondary outcomes were return to the 90-day return to the ED, 90-day readmission, surgical wound infection, thromboembolism, and 90-day mortality. An intention-to-treat (ITT) and as-treated (AT) analyses were performed. RESULTS: Totally, 71 inpatients and 47 outpatients were included. There were no cases of post-operative compartment syndrome. In the ITT analysis, there were no differences for inpatients vs outpatients for 90-day re-admission (22.5% vs 12.8%, p = 0.275), 90-day return to the ED (35.2% vs 17.0%, p = 0.052), infection (12.7% vs 2.1%, p = 0.094), DVT (7% vs 4.3%, p = 0.819), or PE 1.4% vs 0.0%, p = 1.000). The AT analysis showed a significantly higher 90-day re-admission (26.9% vs 2.5%, p = 0.003) and 90-day ED visit (38.5% vs 7.5%, p = 0.001) rate in the inpatient group. CONCLUSIONS: Appropriately selected patients with isolated tibial plateau fractures can have non-inferior rates of compartment syndrome and post-operative complications when compared to inpatients.

Modified frailty index can help predict complications following tibial plateau fracture fixation: a NSQIP study involving 2213 patients.

PURPOSE: The 5-item modified frailty index (mFI-5) has been established as a reliable indicator of poor postoperative outcomes following a variety of orthopaedic procedures. This study aims to determine whether the mFI-5 can be used by surgeons to predict the likelihood of postoperative complications in patients undergoing open reduction internal fixation (ORIF) for tibial plateau fractures. METHODS: From 2006 to 2019, patients aged 50 years or older undergoing ORIF for tibial plateau fracture were identified in the National Surgical Quality Improvement Program database. The mFI-5 was calculated based on the sum of the presence of 5 conditions: diabetes, congestive heart failure, hypertension, chronic obstructive pulmonary disease, and dependent functional status. Chi-squared tests and multivariable regression analysis were used to evaluate the association of different mFI-5 scores with postoperative complications. RESULTS: The study analyzed 2213 patients with an average age of 63 years. Multivariable regression analysis demonstrated that in comparison to patients with a mFI-5 score of 0, those with a score of 1 had an increased risk of prolonged hospital stay (OR 1.31) and discharge to a non-home location (OR 1.50) while those with a score of 2 or greater were at an increased risk of readmission (OR 2.30), wound complication (OR 5.37), pulmonary complication (OR 4.56), urinary tract infection (OR 4.79), prolonged hospital stay (OR 1.89), and discharge to a non-home location (OR 3.01). CONCLUSION: The mFI-5 is a reliable instrument for determining the likelihood of postoperative complications following ORIF for tibial plateau fracture repair. LEVEL OF EVIDENCE: III.

Inorganic carbon utilization strategies of plateau aquatic plants in response to native habitats.

Aquatic plants are a crucial component of the aquatic ecosystem in the Tibetan Plateau region. Researching the adaptability of plateau aquatic plants in photosynthesis to the plateau environment can enhance understanding of the operational mechanisms of plateau ecosystems, thereby providing a scientific basis for the protection and management of plateau aquatic ecosystems. This study presents an investigation of photosynthetic inorganic carbon utilization strategies and photosynthetic efficiency of 17 aquatic plants under natural growing conditions in Niyang River basin on the Tibetan Plateau. In pH-drift experiments, 10 of 17 species were able to utilize HCO3-, and environmental factors like water pH were shown to have a significant effect on the ability of the tested species to utilize HCO3-. Titratable acidity in the leaves of Stuckenia filiformis, Zannichellia palustris, Batrachium bungei, and Myriophyllum spicatum showed significant diurnal fluctuations at certain sampling sites, indicating the presence of CAM. In B. bungei, water pH positively correlated with CAM activity, while CO2 concentration negatively correlated with CAM activity. The chlorophyll fluorescence analysis revealed that aquatic plants inhabiting the Tibetan Plateau exhibited photosynthetic adaptations. In conclusion, the aquatic plants on the Tibetan Plateau employ diverse strategies for utilizing inorganic carbon during photosynthesis, exhibiting their flexible adaptability to the native high-altitude habitats of the Tibetan Plateau.

Effect of jujube orchard abandonment time on soil properties and enzyme activities at soil profile in the Loess Plateau.

In the Loess Plateau, the impact of abandoned farmland on soil properties and enzyme activity, along with its temporal variations and potential driving factors, remains a mystery. This study was designed to systematically and comprehensively examine the variations in soil enzyme activities, particle size distribution, and stability of soil aggregates at different stages of ecological recovery in the Loess Plateau. Our findings reveal a nuanced temporal pattern: with the progression of cropland abandonment, there is a notable decrease in soil bulk density. Concurrently, a dynamic trend in enzyme activities is observed-initially exhibiting a decline, followed by an increase over extended periods of recovery. Notably, prolonged abandonment leads to marked enhancements in soil structure. Parameters such as the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates show an overall increasing trend. In terms of the Relative Dissipation Index (RSI), our data indicate a sequence of control > 2 years of abandonment > 4 years > 6 years > 14 years. From this, it can be seen that fallowing may be an effective natural restoration strategy for improving the physical structure of soils in the Loess Plateau and restoring soil nutrients. However, positive changes may take a long time to become evident.

Intraocular pressure and gonioscopic findings in primary angle-closure disease in India-a big data study.

AIM: To describe the gonioscopic profile and intraocular pressure (IOP) in primary angle-closure (PAC) disease in patients presenting to a tertiary eye care network in India. METHODS: A cross-sectional hospital-based study that included 31 484 new patients presenting between 2011 and 2021. Patients with a clinical diagnosis of PAC/suspect/glaucoma were included. The data was collected from an electronic medical record system. RESULTS: PAC glaucoma (PACG) (47.55%) was the most common diagnosis followed by PAC (39.49%) and PAC suspect (PACS; 12.96%). Female preponderance (54.6%) was noted with higher mean age at presentation among males (P<0.0001). PACS and PAC showed the highest prevalence in 6th decade but PACG was higher at 7th decade. The probability of angle opening was 95.93%, 90.32% and 63.36% in PACS, PAC and PACG eyes respectively post peripheral iridotomy (PI). Plateau iris syndrome (PIS) was noted in 252 eyes and all showed post dilated rise of IOP. A post dilated IOP rise was also noted with 8.86%, 33.95% and 57.19% eyes with PACS, PAC and PACG respectively with IOP rise between 6-8 mm Hg across the disease spectrum. CONCLUSION: The superior quadrant is the narrowest angle and difficult to open with indentation and post PI. The probability of angle opening is less in PIS especially the complete variety along with post dilated IOP rise. The post dilated IOP rise in angle closure eyes warrants a careful dilatation, especially with PIS.

The complete plastome of Thalictrum elegans Wall. ex Royle and its phylogenetic analysis.

Thalictrum elegans Wall. ex Royle, a species within the family Ranunculaceae, is mainly distributed along forest margins and grassy slopes at altitudes 2700-4000 m on the Qinghai-Tibetan Plateau. Despite its wide distribution in alpine ecosystems, its genetic diversity remains poorly understood. In this study, we assembled and characterized the complete chloroplast genome of T. elegans, addressing a significant gap in our understanding of its genetic composition. The chloroplast genome is 155,864 base pairs long and contains 131 genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis of 15 representative Thalictrum species revealed that the genus can be classified into three clades. T. elegans along with another nine other species formed the largest monophyletic clade and is most closely related to T. petaloideum and T. foliosum. These findings enhance our understanding of the genetic diversity of T. elegans and contribute to its conservation and utilization.

The enhanced neutral process with decreasing cell size: a study on phytoplankton metacommunities from the glacier-fed river of Qinghai-Xizang Plateau.

The cell size of phytoplankton is an important defining functional trait that can serve as a driver and sentinel of phytoplankton community structure and function. However, the study of the assembly patterns and drivers of phytoplankton metacommunities with different cell sizes has not been widely carried out. In this study, we systematically investigated the biodiversity patterns, drivers, and assembly processes of the three phytoplankton cell sizes (micro: 20-200 µm; nano: 2-20 µm; pico: 0.2-2 µm) in the Za'gya Zangbo River from the source to the estuary using 18S rDNA amplicon sequencing. The results demonstrated that the alpha diversity and co-occurrence network complexity for all three sizes of phytoplankton increased to a peak downstream of the glacier sources and then decreased to the estuary. The nanophytoplankton subcommunity consistently had the highest alpha diversity and co-occurrence network complexity. On the other hand, total beta diversity followed a unimodal trend of decreasing and then increasing from source to estuary, and was dominated by species replacement components. In addition, deterministic processes driven mainly by physiochemical indices (PCIs) and biogenic elements (BGEs) dominated the assembly of micro- and nanophytoplankton subcommunities, whereas stochastic processes driven by geographical factors (GGFs) dominated the assembly of picophytoplankton subcommunities. The results explained the contradictions in previous studies of phytoplankton community assembly processes in highland aquatic ecosystems, elucidating the different contributions of deterministic and stochastic processes, and the complexity of compositional mechanisms in shaping the assembly of micro-, nano-, and picophytoplankton in this highland glacial river. IMPORTANCE: The cell size of phytoplankton is a key life-history trait and key determinant, and phytoplankton of different cell sizes are differentially affected by ecological processes. However, the study of the assembly patterns and drivers of phytoplankton metacommunities with different cell sizes has not been widely carried out. We provide an in-depth analysis of phytoplankton community diversity across three cell sizes in the glacier-fed river, describing how the pattern of phytoplankton communities differs across cell sizes in response to geochemical gradients. The results show that the smaller phytoplankton (picophytoplankton) are relatively more influenced by dispersal-based stochastic processes, whereas larger ones (microphytoplankton and nanophytoplankton) are more structured by selection-based deterministic processes.

Investigating subsurface structural lineaments of the northwest Ethiopian plateau using gravity data.

This study provides advanced knowledge of the subsurface structural characteristics of the northwest Ethiopian plateau. With its complex geologic structure, the Northwest Ethiopian plateau is being studied for density boundary mapping using geophysical methods. However, its application to the mapping of geological structures such as faults and contacts which appear as lineaments in gravity data has not been studied so far. Thus, the goal of this research is to increase our understanding of the subsurface structural lineaments and their depth beneath the Ethiopian plateau in the northwest using global gravity model GGMplus2013. These subsurface structural lineaments and their depths were investigated using the LTHG, EHGA, and tilt depth techniques. The results indicate that the main subsurface structural lineaments identified in the study region are dipping between 3.2 and 8 km and are developing in the NE-SW, N-S, E-W, and NW-SE orientations.

Tibetan lake sediment records reveal historical emission and long-range atmospheric transport of chlorinated paraffins.

The Tibetan Plateau, a recognized global sink for Persistent Organic Pollutants (POPs), lies adjacent to two major emitting regions, inland China and India. This unique geographical setting makes it a pivotal site for examining the presence and compositional evolution of POPs following their long-range atmospheric transport (LRAT). This study focuses on the current predominant POPs, chlorinated paraffins (CPs). We comprehensively screened 675 homologues of the very short- (vSCCPs), short- (SCCPs), medium- (MCCPs), and long-chain CPs (LCCPs) in six dated sediment cores across the extensive Tibetan area. The findings unveiled pronounced temporal disparities in CP concentrations and compositions between Tibet's southern and eastern sectors, reflecting divergent usage and emission chronicles of inland China and India. Notably, a market shift in China from regulated SCCPs to the in-use MCCPs and LCCPs was observed in the 21st century, contrasting with India's unregulated production of SCCPs. The Organization for Economic Cooperation and Development (OECD) Screening Tool, developed to assess the overall persistence (POV) and long-range transport potential (LRTP) of organic chemicals, elucidated the erosion of CP source signatures induced by fractionation, a process that intensifies with transport distance from the source regions. This study enhances our understanding of the emission inventories and LRAT behavior of these transitional regulatory contaminants, highlighting the Tibetan Plateau's crucial role as an environmental sentinel in global pollution dynamics.

Assessments of various precipitation product performances and disaster monitoring utilities over the Tibetan Plateau.

The Tibetan Plateau, often referred to as Asia's water tower, is a focal point for studying spatiotemporal changes in water resources amidst global warming. Precipitation is a crucial water resource for the Tibetan Plateau. Precipitation information holds significant importance in supporting research on the Tibetan Plateau. In this study, we estimate the performance and applicability of Climate Prediction Center Merged Analysis of Precipitation (CMAP), Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG), Global Land Data Assimilation System (GLDAS), and Global Precipitation Climatology Project (GPCP) precipitation products for estimating precipitation and different disaster scenarios (including extreme precipitation, drought, and snow) across the Tibetan Plateau. Extreme precipitation and drought indexes are employed to describe extreme precipitation and drought conditions. We evaluated the performance of various precipitation products using daily precipitation time series from 2000 to 2014. Statistical metrics were used to estimate and compare the performances of different precipitation products. The results indicate that (1) Both CMAP and IMERG showed higher fitting degrees with gauge precipitation observations in daily precipitation. Probability of detection, False Alarm Ratio, and Critical Success Index values of CMAP and IMERG were approximately 0.42 to 0.72, 0.38 to 0.56, and 0.30 to 0.42, respectively. Different precipitation products presented higher daily average precipitation amount and frequency in southeastern Tibetan Plateau. (2) CMAP and GPCP precipitation products showed relatively great and poor performance, respectively, in predicting daily and monthly precipitation on the plateau. False alarms might have a notable impact on the accuracy of precipitation products. (3) Extreme precipitation amount could be better predicted by precipitation products. Extreme precipitation day could be badly predicted by precipitation products. Different precipitation products showed that the bias of drought estimation increased as the time scale increased. (4) GLDAS series products might have relatively better performance in simulating (main range of RMSE: 2.0-4.5) snowfall than rainfall and sleet in plateau. G-Noah demonstrated slightly better performance in simulating snowfall (main range of RMSE: 1.0-2.1) than rainfall (main range of RMSE: 2.0-3.8) and sleet (main range of RMSE: 1.5-3.8). This study's findings contribute to understanding the performance variations among different precipitation products and identifying potential factors contributing to biases within these products. Additionally, the study sheds light on disaster characteristics and warning systems specific to the Tibetan Plateau.