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Understanding long-term dynamics is vitally important for explaining current biodiversity patterns and setting conservation goals in a changing world. However, the changes in biodiversity in time and space, particularly the dynamics at the centuries or even longer time scales, are poorly documented because of a lack of continuous monitoring data. The sedimentary DNA (sedDNA) has a great potential for paleo-community reconstruction, and it has recently been used as a powerful tool to characterize past dynamics in terms of biodiversity over geological timescales. In particular, it is useful for prokaryotes and eukaryotes that do not fossilize; hence, it is revolutionizing the scope of paleoecological research. Here, a "Research Weaving" method was performed with systematic maps and bibliometric webs based on the Web of Science for Science Citation Index Expanded, presenting a comprehensive landscape of the sedDNA that traces biological dynamics. We identified that most sedDNA-based studies have focused on microbial dynamics and on using samples from multitypes of sediments. This review summarized the advantages and common applications of sedDNA, focused on the biodiversity in microbial communities, and provided an outlook for the future of sedDNA research.

The history of forager subsistence strategies on the Tibetan plateau during the middle Holocene has been studied extensively, with valuable results from archaeozoology and archaeobotany being produced in recent years. However, changes to the resources collected by the foragers and the factors that influence them have rarely been discussed. Here we examine the differences and factors influencing charcoal identification and analysis results from both hand picking and flotation recovery methods at the Zongri site, revealing more accurately the use of firewood by the foragers and its relationship with climate change and the agricultural population. Our results show that there is a clear deficiency in tree taxa arising from hand picking, perhaps related to the quantity of charcoal collected and identified. The Zongri people mainly used nearby trees and shrubs, including Picea (spruce), Populus (poplar) and Hippophae (sea buckthorn). The material collected was dominated by green (living) wood, which might have been influenced by the farming culture in the adjacent area. The increasing use of Picea may be attributed to the selective collection of wood by the Zongri foragers, and not caused by climate change.

To understand the lake status and reasons of eutrophication at Lake Erhai in recent years, water quality, including water temperature (T), pH, dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP) and chlorophyll-a (Chl-a) from 2016 to 2020 was monitored and analyzed. The results showed no obvious thermocline in the vertical direction at Lake Erhai, while Chl-a demonstrated obvious spatiotemporal distribution characteristics in Lake Erhai. Chl-a concentrations increased to a maximum in summer in August with the low TN:TP value, leading to algal blooms, most notably in the southern lakes. Low pH and DO appeared due to the thermocline of Erhai Lake (August 2016). A large area of algae distribution due to the increase of total phosphorus appeared in the northern lake area of Lake Erhai in December 2016, with a tendency of mesotrophic to light eutrophic in summer by the nutritional evaluation of Lake Erhai, especially in the central lake area and the northern lake area. Pearson’s correlation coefficient and principal component analysis showed a significant positive correlation between Chl-a and T (r = 0.34, p ≤ 0.01) and TP (r = 0.31 p ≤ 0.01) in the mesotrophic Lake Erhai, indicating that TP content was one of the triggering factors for the algal blooming. Based on the spatiotemporal changes in water quality parameters and their relationship with eutrophication, scientific agencies should implement management strategies to protect Lake Erhai, supplemental to the costly engineering measurements.

Eutrophication remediation is an ongoing priority for protecting aquatic ecosystems, especially in plateau lakes with fragile ecologies and special tectonic environments. However, current strategies to control the phosphorus (P) and nitrogen (N) levels in eutrophication sites have been mainly guided by laboratory experiments or literature reviews without in-field analyses of the geochemical processes associated with the hydrological and eutrophic characteristics of lakes. This study analyzed the water quality parameters of 50 sites at Lake Jian in May 2019, a moderate eutrophication shallow plateau lake, based on dissolved/sedimentary nitrogen, phosphorous and organic matter, grain size, C/N ratios and stable isotope ratios of δ13C or δ15N in sediments. The results showed that the average total nitrogen (TN) and total phosphorus (TP) concentrations in the lake water were 0.57 mg/L and 0.071 mg/L, respectively. The TN and TP contents of surface sediment ranged from 2.15 to 9.55 g/kg and 0.76 to 1.74 g/kg, respectively. Stable isotope and grain source analysis indicated that N in sediments mainly existed in organic matter form and P mainly occurred as inorganic mineral adsorption. Endogenous pollution contributed to >20% of TN. Furthermore, our findings showed that phosphorus was the nutrient that limited eutrophication at Lake Jian, unlike other eutrophic shallow lakes. In contrast, the nutrient levels in the sediment and input streams belonged entirely to the N-limitation state. The distinctness in release intensity of N and P could modify the N/P limitation in the lake, which affects algae growth and nutrient control. These results demonstrated that reducing exogenous nutrients might not effectively mitigate lake eutrophication due to their endogenous recycling; thus, detailed nutrient monitoring is needed to preserve aquatic ecosystems.

The ancient Silk Road played a crucial role in cultural exchange and commercial trade between western and eastern Eurasia during the historical period. However, the exchanges were interrupted in the early 16th century CE, during the Ming dynasty. Various causes for the decline of the ancient Silk Road have been suggested. Unlike social factors, natural factors have not been adequately addressed. In this study, we use evidence from a sedimentary site (Xishawo, XSW) in Dunhuang oasis, together with analysis of historical archives, to demonstrate the occurrence of extreme droughts and desertification events in the Dunhuang area post ∼ 1450 CE, which persisted at least for decades. The desertification may be closely associated with the accessibility of the ancient Silk Road in the area, which was responsible for a steep fall in the volume of trade, as well as political chaos and mass migrations. Therefore, besides socio-economic factors, climate change may have played an important role in trade exchange between the Ming government and the West and may have even influenced the rise and decline of the ancient Silk Road.

The effects of anthropogenic activity and climate change on lake ecosystems for nine large plateau lakes in Yunnan Province have recently received much attention; however, most studies have focused on the deepest lake sediments and ignored the lake sediments adjacent to the populated area. To evaluate the sedimentation rates and ecological changes, four 210Pb- and 137Cs-dated sediment cores were collected along the long axis of Yangzong Lake, a fault-controlled north-south strike lake located in Yunnan Plateau in July 2006 and July 2016, respectively. We combined a biological indicator (diatom assemblage) with geochemical indicators (total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP)) for core S0 in the southern part of the lake to examine the ecological changes in response to anthropogenic disturbances within the lake over the last 60 years. The results showed that the sedimentation rate in the southern part of the lake (S1) was significantly higher than that in the central (S2) and northern (S3) parts of the lake. Redundancy analysis (RDA) and Pearson correlation analysis identified significant correlations between TP and Aulacoseira granulata, Cyclotella ocellata, and Cyclotella rohomboideo-elliptica (correlation coefficients: − 0.66, − 0.63, and 0.81, respectively, p < 0.01). There was a clear shift in the diatom community from oligotrophic to eutrophic species becoming dominant after the 1990s, coinciding with the intensifying human activities around the lake. Furthermore, there were two periods of diatom absence in core S0, which was associated with two periods of rapid depositional events. These are likely associated with the intensification of industry, mining, road construction, and agriculture within the lake catchment. These findings highlight the sensitivity of freshwater ecosystems in the shallow-water area of a lake to human activities, with implications for future water quality in fault-controlled lakes.

Changes in moisture conditions or precipitation in the SE Tibetan Plateau during the Holocene have been studied using various environmental archives and proxies. However, due to different interpretations of the proxies and records, the pattern of Holocene precipitation/moisture variations in the region remains unclear. A lake-sediment-based reconstruction of runoff variations, which can directly and sensitively reflect changes in precipitation, provides the opportunity to reconstruct the evolution of moisture conditions in the SE Tibetan Plateau during the Holocene. In this study, we used a well-dated sediment core (LGH2) from Lake Lugu, a deep alpine lake charged mainly by precipitation on the lake surface and by runoff from the watershed, to reconstruct variations in runoff during the Holocene. In addition, 70 lake surface sediment samples were collected to examine the spatial variation of grain size. Endmember modeling analysis of the grain-size data was used to characterize the processes of sediment transport and runoff fluctuations. The carbonate content of core LGH2 shows that the lake level was generally high during 11,600–3100 cal years BP, and that the lake basin was closed after 3100 cal years BP and semi-closed since 90 cal years BP. Grain-size endmember EM 3, which represents the runoff input clastic materials, is used to reconstruct runoff fluctuations in the Lake Lugu watershed. The record indicates a gradual increase in runoff during 11,600–9000 cal years BP, stable and high runoff during 9000–2000 cal years BP, and weak runoff and a low lake level since 2000 cal years BP. Our reconstruction of runoff fluctuations tracks changes in regional temperature and tropical SSTs rather than in boreal summer insolation. This finding supports the hypothesis that increasing tropical SSTs strengthened ITCZ convection which enhanced the flux of water vapour from the ocean to the air, and hence the moisture supplies to SW China.

Archaeological research has documented the migration of Neolithic farmers onto the Tibetan Plateau by 4000 BC. How these incoming groups interacted, if at all, with local indigenous foragers, however, remains unclear. New archaeobotanical and zooarchaeological data from the Zongri site in the north-eastern Tibetan Plateau suggest that local foragers continued to hunt but supplemented their diet with agricultural products in the form of millet. The authors propose that, rather than being grown locally, this millet was acquired via exchange with farmers. This article highlights how indigenous foragers engaged in complex patterns of material and cultural exchange through encounters with newly arrived farmers.

The development and subsistence strategies adopted in ancient settlements are crucial to the understanding of long-term human–environmental interaction in the past. Here, we reassess the chronology of the ancient walled settlement of Sanjiao in the Hexi Corridor in northwestern China through accelerator mass spectrometry radiocarbon (AMS14C) dating and explore the subsistence of the settlers inside through the identification of carbonized seeds and charcoal. In addition, high-resolution paleoclimate records in the Hexi Corridor and nearby regions are employed to explore the reason for the construction of Sanjiao. Our results show that Sanjiao was built around 828 cal BC and remained inhabited through 384–116 cal BC. This indicates Sanjiao is the earliest known walled settlement in the Hexi Corridor. Ancient people at Sanjiao consumed crops such as barley, broomcorn millet, and foxtail millet, and used wood fromTamarix chinensis,Tamarix,Salix,Picea,Hippophae,Betulaceae, andPoaceaeas fuel. The construction date of Sanjiao correlates with climate deterioration and social upheavals in the Hexi Corridor, potentially suggesting a defensive purpose for the site.

In recent years, archaeologists have studied how ancient humans have shaped, and been shaped by, their surrounding environments in an effort to provide valuable insight into the patterns of human-environment interaction during prehistoric and historical periods. Along the Heihe River in Hexi Corridor of northwest China, archaeologists have found many ancient cities that are good places to explore changes in human settlement patterns in relation to environment change in historical periods. In this paper, we present our investigation of seven ancient cities to clarify the chronology of these cities and their strategy for wood use in the area through the application of radiocarbon dating and charcoal identification. Our results suggest that the ages of many cities are younger than previous estimates, and humans mainly used Tamarix and mixed Tamarix and broad leaf trees in the lower and middle reaches of the Heihe River basin between ∼ AD 240–1380 respectively, and roughly matches the modern spatial distribution of natural woody vegetation in the area. In comparison to the results of archaeological, paleoclimatic and historical studies in Hexi Corridor, we propose that ancient human strategies for wood use and their impact on environment of the Heihe Basin are primarily relevant to human lifestyles rather than climate change.

Charcoal remains from archeological sites are used not only to reconstruct the historical composition of local woodlands but also to examine the history of the human use of wood. Nevertheless, key questions such as how and why people may have selected particular woody taxa from locations long distances from their habitat have rarely been addressed. In the present study, we analyze charcoal remains from the ancient Jingbaoer (JBR) jade mine in the Mazong Mountains (Mazong Shan) of Northwest China to explore patterns in the collection and use of wood by Iron Age people. Factors affecting the choice of wood collected at the JBR site are discussed by combining the results of pollen records and charcoal analysis. Our results suggest that tamarisk (Tamarix L.), a shrub dominant in the local area, was the main source of wood for JBR miners and was used as firewood depending upon its local availability. The miners may also have used wood from species sourced further away, such as Pinus L. and Picea L., because of the local scarcity of these trees in such a dry environment. The agropastoralist subsistence system practiced by the JBR miners supports the hypothesis of the collection of wood from distant locales. This study highlights diverse patterns of wood collection in an area scarce in woody plants and provides new evidence for understanding how Iron Age people adapted to extremely arid environments.

Contemporary studies emphasize theoretical and analytical aspects of monitoring water quality within lacustrine settings. The X-ray fluorescence (XRF) core scanner provides the most rapid, non-destructive high-resolution elemental measurements for unprocessed sediments. However, the analytical precision of measured elemental composition may be offset due to water content and inhomogeneities in the physical properties of the sediment. A range of calibration approaches developed specifically for converting XRF scanning intensities to element fractions has been made available. Here, two lake sediment-cores retrieved from southwest China were used to evaluate the performance of various calibration methods. In particular, the influence of sediment properties on XRF scanning intensities was assessed by redundancy analyses (RDA) and the generalized additive model (GAM). The results demonstrate that for fine-grained sediments, the impact of grain size results in only minor deviations in the XRF scanning intensities. Water content of the lake sediment was shown to be the most important factor influencing the XRF scanning intensities, especially for light elements (e.g., Al to Fe). Significant decreases in XRF scanning intensities may occur when sediment water content is greater than 47%. We recommend testing the element fractions obtained via conventional techniques throughout the core and applying the multivariate log-ratio calibration for high-resolution XRF scanning elements within lake sediments.

Graphene photocatalysis is receiving increased attention for its potential to be used as a novel green technology for mitigating harmful algae in highly eutrophic waters. However, graphene is seldom applied to in situ aquatic ecosystems for environmental applications. Here, the impacts of graphene photocatalysis on phytoplankton and environmental conditions were evaluated through an in situ macrocosm experiment in the eutrophic Lake Xingyun, southwestern China. The graphene photocatalysis treated area had significantly reduced conductivity, total nitrogen (TN), total phosphorus (TP) and dissolved phosphorus concentrations, as well as increased dissolved oxygen (DO) concentrations. The abundances of all species of the genus Microcystis were significantly reduced in the graphene photocatalysis-treated area; in contrast, the abundances of all species of the diazotrophic genera, including Anabaena and Aphanizomenon, greatly increased after treatment with graphene photocatalysis. Eukaryotic algae, especially Chlorophyta, Euglenophyta and Pyrrophyta, as well as Cryptophyta, had significantly higher abundances in the graphene photocatalysis-treated area, whereas most of the eutrophic diatom species had lower abundances in the treated area. These observed differences in eukaryotic algae between the two groups might be related to their sensitivity to graphene photocatalysis and their tolerance of nutrients. Generally, graphene photocatalysis can make a great contribution to the improvement of eutrophic water, as evidenced by the reduction in cyanobacteria abundance and phosphorus concentration, as well as the increase in species richness and the dissolved oxygen concentration in the treated area. However, the mechanisms underlying these differences in phytoplankton community structure and environmental conditions require further study.

The Neolithic period witnessed the start and spread of agriculture across Eurasia, as well as the beginning of important climate changes which would take place over millennia. Nevertheless, it remains rather unclear in what ways local societies chose to respond to these considerable changes in both the shorter and longer term. Crops such as rice and millet were domesticated in the Yangtze River and the Yellow River valleys in China during the early Holocene. Paleoclimate studies suggest that the pattern of precipitation in these two areas was distinctly different. This paper reviews updated archaeobotanical evidence from Neolithic sites in China. Comparing these results to the regional high-resolution paleoclimate records enables us to better understand the development of rice and millet and its relation to climate change. This comparison shows that rice was mainly cultivated in the Yangtze River valley and its southern margin, whereas millet cultivation occurred in the northern area of China during 9000&ndash, 7000 BP. Both millet and rice-based agriculture became intensified and expanded during 7000&ndash, 5000 BP. In the following period of 5000&ndash, 4000 BP, rice agriculture continued to expand within the Yangtze River valley and millet cultivation moved gradually westwards. Meanwhile, mixed agriculture based on both millet and rice developed along the boundary between north and south. From 9000&ndash, 7000 BP, China maintained hunting activities. Subsequently, from 7000&ndash, 6000 BP, changes in vegetation and landscape triggered by climate change played an essential role in the development of agriculture. Precipitation became an important factor in forming the distinct regional patterns of Chinese agriculture in 6000&ndash, 4000 BP.

The Ancient Silk Road played a crucial role in cultural exchange and commercial trade between western and eastern Eurasia during the historical period. However, the exchanges were interrupted in the early 16th century AD, in the Ming dynasty. Three causes of the demise of the ancient Silk Road have been suggested: (1) the thriving of the sea trade route after the great geographic discovery in the Ming dynasty; (2) frequent incursions by the Wala and Turpan kingdoms, or fighting in border areas; and (3) climate change. In this study, new evidence from a sedimentary site in Dunhuang oasis together with analysis of historical archives indicate that neither the sea trade route nor the frontier wars were the pivotal reason for the closure of the Jiayuguan Pass. Extreme droughts and desertification events, caused by climate change, occurred in the Dunhuang area, west of the Jiayuguan Pass, during ~ 1440–1460 AD. After ~ 1450 AD, desertification rendered the ancient Silk Road impassable in the area, which resulted in a steep fall in the volume of trade as well as political chaos and mass migrations. The final closure of the Jiayuguan Pass in 1539 AD and the abandonment of Dunhuang city further interrupted the operation of the ancient Silk Road.

The study of the coupling relationship between climate change and civilization evolution along the Ancient Silk, can provide valuable insights for understanding the history, pattern and mechanism of man-land relation evolution from a long-run perspective. Here we provide two case studies from the Hexi Corridor and Qaidam basin in northwest China, where locates at eastern Ancient Silk Road, and became a center for trans-continental exchange since the second Millennium BC, hydrological change in these areas is very drastic. The results reveal three significant desertification events occurred in these two areas during late Holocene, which was likely related to precipitation variation in surrounding mountains instead of basins, and triggered the shrinkage of ancient oases and then the decline of ancient civilizations. We also try to explain the linkage between climate change and the evolution of ancient civilizations in the two areas.

Changing ecological communities in response to anthropogenic activities and climate change has become a worldwide problem. The eutrophication of waterbodies in freshwater and seawater caused by the effects of human activities and nutrient inputs could result in harmful algae blooms (HABs), decreases water quality, reductions in biodiversity and threats to human health. Rapid and accurate monitoring and assessment of aquatic ecosystems are imperative. Environmental DNA (eDNA) analysis using high-throughput sequencing has been demonstrated to be an effective and sensitive assay for detecting and monitoring single or multiple species in different samples. In this study, we review the potential applications of eDNA approaches in controlling and mitigating eutrophication and HABs in freshwater and marine ecosystems. We use recent studies to highlight how eDNA methods have been shown to be a useful tool for providing comprehensive data in studies of eutrophic freshwater and marine environments. We also provide perspectives on using eDNA techniques to reveal molecular mechanisms in biological processes and mitigate eutrophication and HABs in aquatic ecosystems. Finally, we discuss the feasible applications of eDNA for monitoring biodiversity, surveying species communities and providing instructions for the conservation and management of the environment by integration with traditional methods and other advanced techniques.

Supplemental material, sj-pdf-1-hol-10.1177_0959683620972777 for Sedimentary grain-size record of Holocene runoff fluctuations in the Lake Lugu watershed, SE Tibetan Plateau by Xiaonan Zhang, Hucai Zhang, Fengqin Chang, Umar Ashraf, Han Wu, Wei Peng, Qi Liu, Fengwen Liu, Yun Zhang and Lizeng Duan in The Holocene

Trapa japonica was observed to have inhibiting effects and could be used as a potential environment-friendly control strategy for cyanobacterial blooms in freshwater. However, the changes and effecting mechanisms in eukaryotic and prokaryotic communities by T. japonica are not yet clear. In this study, the effects of T. japonica on microbial communities were assessed in Lake Qionghai and Lake Erhai by 18S rRNA and 16S rRNA amplicon sequencing, respectively. The results showed that T. japonica can improve biodiversity and change the microbial community structures to varying degrees in both lakes. The alpha diversity indexes of microbial communities (e.g., Shannon, Sobs, Ace and Chao 1) were higher in the water inhabited by T. japonica (TJ group) than the water uninhabited by T. japonica (control) (P 0.05). The PCoA results suggested that the microbial community compositions differed between the two groups (PERMANOVA P = 0.001). In Lake Qionghai, the relative abundances of dominant taxa and nutrients level showed little differences between the two groups. These may result from the homogenous water condition in Lake Qionghai. While the genera Cyanobium_PCC-6307, the majority of Cyanobacteria, decreased significantly in TJ group than control according to 16S rRNA gene sequencing. In Lake Erhai, environmental variables were distinctly affected by T. japonica, which was found to drive Cryptophyceae to become the main taxa through taxonomic analysis of 18S rRNA. Based on 16S rRNA gene sequencing, T. japonica reduced the relative abundance of Cyanobacteria, such as Planktothrix_NIVA-CYA_15 and Cyanobium_PCC-6307, by enriching cyanobactericidal bacteria and growth-inhibiting bacteria (e.g., Limnohabitans and Flavobacterium) and changing environmental parameters. Our results revealed that T. japonica acts in shaping microbial communities in lakes on the community level, shedding new lights on eutrophication mitigation, one of the most serious global ecological problems we are facing.

The tight gas reserves in the Hangjinqi area are estimated at 700 × 109 m3. Since the exploration of the Hangjinqi, numerous wells are already drilled. However, the Hangjinqi remains an exploration area and has yet to become a gas field. Identifying a paleo-depositional framework such as braided channels is beneficial for exploration and production companies. Further, braided channels pose drilling risks and must be properly identified prior to drilling. Henceforth, based on the significance of paleochannels, this study is focused on addressing the depositional framework and sedimentary facies of the first member (P2x1) of the lower Shihezi formation (LSF) for reservoir quality prediction. Geological modeling, seismic attributes, and petrophysical modeling using cores, logs, interval velocities, and 3D seismic data are employed. Geological modeling is conducted through structural maps, thickness map, and sand-ratio map, which show that the northeastern region is uplifted compared to northwestern and southern regions. The sand-ratio map showed that sand is accumulated in most of the regions within member-1. Interval velocities are incorporated to calibrate the acoustic impedance differences of mudstone and sandstone lithologies, suggesting that amplitude reflection is reliable and amplitude-dependent seismic attributes can be employed. The Root Mean Square (RMS) attribute confirmed the presence of thick-bedded braided channels. The results of cores and logging also confirmed the presence of braided channels and channel-bars. The test results of wells J34 and J72 shows that the reservoir quality within member-1 of LSF is favorable for gas production within the Hangjinqi area.

Lake Dian, the largest lake on South China’s Yunnan-Guizhou Plateau, exhibits two abnormal funnel-like features in the deepest part of the lake. Nevertheless, how and when these funnels formed and their implications and potential environmental and ecological effects remain unclear. To address these questions, we carried out a detailed multi-method survey including underwater topographic monitoring, extraction of sediment records, and geophysical exploration across the funnel areas. Sediment records revealed a significant sedimentation hiatus around these features. For example, sediments with thicknesses of ca. 69.24 cm and 83.56 cm in cores D4 and D6 were eroded based on the calculated of sedimentation rates. Deformed sedimentary structures and a hiatus, together with large-scale funnel-shaped topography, prove that underlying karst collapse may trigger massive water outflow through these funnels, which could result in an erosional hiatus in the local lakebed. Continuous clay deposits in the upper part of the sedimentary column suggest that water leakage may have ceased since the 1930s. However, bathymetric surveys conducted in October 2015 and September 2019 indicated that the maximum lake depth increased by 0.97 m and 0.2 m in the large and small funnels, respectively, over this 4-year period. The corresponding increased volumes were 1520 m3 and 375 m3 in the large and small funnels, respectively. Numerous pits were distributed around the funnels. Cumulatively, these underwater topographic changes reveal that small-scale, slow water leakage has been developing, which could potentially trigger catastrophic water discharge due to increasing hydraulic pressure and/or underlying karstification. If catastrophic water outflow occurs, ~14.05 × 108 m3 of highly polluted water would not only contaminate the upper reaches of the large river and/or the lake itself, but would also endanger regional water security and induce widespread negative ecological impacts.

Anthropogenic disturbances have been widely documented to affect organic matter (OM) sources in lakes; however, most studies have revealed the unreliability of estimating ecological changes from a single or a few sediment cores within a single lake. Here, we combined multi-core analyses, including total organic carbon and total nitrogen contents and their stable carbon and nitrogen isotope ratios (δ13Corg and δ15N, respectively) with a Bayesian isotope mixing model to track the origins of OM and characterize the environmental changes in Lake Yangzong, a plateau lake located in the Yunnan Plateau, Southwest China. The results showed that allochthonous OM (C3 plants: 31.2–78.3%; soil OM: 4.4–26.6%) was the dominant sediment OM source, and the contributions of plankton, soil OM, and sewage decreased from the south to the north. The temporal increase in δ15N might have indicated an increase in nitrogen discharge caused by human activities, whereas the variation of δ13Corg was mainly controlled by allochthonous sources. Further analysis showed that there were significant differences in the lake environment evolution at different sites from the 1950s in response to anthropogenic disturbances. For example, there was a significant shift in the lake environment at the southern site (S1) from the 1990s, whereas a rapid environmental change was documented at the middle site (S2) over the past half-century. Rapid environmental fluctuation occurred at the northern site (S3) owing to soot air pollution occurring on the north shore of the lake from 1970 to 1990. These findings reveal the spatiotemporal characteristics of ecological changes and highlight the sensitivity of the deep-water area of deep lakes to anthropogenic disturbances.

The rise and fall of ancient cultures and civilizations is a hotly debated topic that has generated disagreements and disputes. In this paper we summarize some case studies on the abandonment of ancient sites, the prosperity and collapse of ancient cultures, and demographic changes, as well as the influence of environment and technology during the prehistoric and historic periods. We then suggest that the dominant influencing factors for the evolution of ancient societies vary by spatial scale. At the local scale, sudden disasters are critical factors leading to the destruction and abandonment of large settlements. On a regional scale, climatic variations (e.g., droughts or cold events lasting for decades or centuries) are important factors that induce the collapse of ancient civilizations and mass migrations, while an enduring and stable optimal climate facilitated the prosperity of ancient civilizations. On a global scale, major technological innovations and their dispersion lasting for centuries and even millennia are major catalysts for population growth and social development. Lastly, we illustrate a possible mechanism under which environmental and technological factors played a critical role in ancient human survival and social evolution on different spatial scales.

Many ancient cities and settlement sites have been found in Lucaogou, an ancient oasis near Dunhuang city in northwest China. These settlements indicate that humans inhabited this area during the historical period. However, the chronology and subsistence practices of this area remain unclear. Based on new data from radiocarbon dating, macrobotanical analysis, and the synthesis of historical documents and high-resolution paleoclimatic records, we discuss the inter-relationship between human settlements and plant resource utilization strategies at Lucaogou ancient oasis during historical period. Our results indicate that these ancient sites in Lucaogou area were built between the Han dynasty (202 BC-AD 220) and the Ming dynasty (AD 1368-AD 1644). People mainly used foxtail millet, broomcorn millet, barley and three types of wood ( Tamarix , Salix , Populus ), probably as fuel for cooking. Human settlement intensity in the area during the historical period was primarily influenced by political situations, which might also have been affected by fluctuations in precipitation.

All around the world, ancient legends exist about the Great Flood, and the influence of the Great Flood in human evolutionary history is a hotly debated topic. In China, the legend of the prehistoric Great Flood and Yu the Great’s flood control has a long history and is considered to be closely linked to the establishment of the Xia Dynasty. However, there is a lack of solid scientific evidence. Against this issue, some scholars have proposed that an earthquake around 1920 BCE in the Guanting Basin along the upper reaches of the Yellow River led to the creation of a lake by damming in the Jishi Gorge and that the outburst of water from that lake led to the massive flood in the Yellow River region. These studies provided new scientific evidence for the Chinese legend. In this paper, we date skeletal samples embedded in earthquake sand blasting from the Lajia site, analyze remains from natural disasters (such as earthquakes and floods) and also archaeological remains. In addition, we compared the skeletal samples dating with that of sediments from the dammed-up lake. Our results are inconsistent with those of previous scholars. The earthquake at the Lajia site occurred no earlier than 1800 BCE, and the dammed-up lake in Jishi Gorge had disappeared by 3600 BCE. Thus, the formation and outburst of the dammed lake, the sudden death of ancient humans at the Lajia site and the ancient earthquake were independent events occurring at different times. In addition, the massive flood in the upper reaches of the Yellow River did not actually happen. Thus, we argue against and invalidate the hypothesis that the massive flood was related to Yu the Great’s flood control and the establishment of the Xia Dynasty.

In northwestern China, many historical nomadic kingdoms and Chinese dynasties sought to control the Heihe River basin, an important location on the eastern part of the ancient Silk Road. Archaeologists have argued that changes in material culture are tied to the frequent turnover in polities in the area, but no published evidence supports these claims. In this paper, we evaluate the relative importance of environmental and political factors in determining the spatiotemporal pattern of archaeological sites in the middle and lower reaches of the Heihe River basin by using previously published high-resolution paleoclimate records and a variety of historical documents. Our results indicate that humans intensively exploited the Heihe River basin during Han dynasty (202BC–AD 220). Following the Han dynasty, during the Wei-Jin (AD 222–589) and Sui-Tang (AD 581–907) periods the number of archaeological sites. In the Western Xia-Yuan period (AD 1038–1368), people mainly settled in the lower reaches of the Heihe River basin and only returned to the middle reaches of the Heihe River basin during the Ming and Qing dynasties (AD 1368–1912). Although climate change and the local environment affected human activities in Heihe River basin, geopolitical events, such as forced mass migrations, are more responsible for influencing the distribution of archaeological sites over the past 2000 years.

Accumulations of aeolian deposits in a range of sedimentary environments provide evidence for past changes in atmospheric circulation patterns over a range of spatiotemporal scales. As yet, there have been relatively few studies of aeolian records in Southwestern (SW) China, and thus there is hitherto untapped potential of using such records to reveal regional atmospheric circulation. Rare earth element (REE) and grain-size analyses were carried out on a well-dated sediment core from Lake Lugu, SW China, to establish the provenance of aeolian deposits preserved within the lake during the last 32 kyr. The core sediments (LGH2) possess high δEuN values (0.73–0.87) and exhibit a moderate REE abundance (156–274 ppm). The δEuN-∑REE pattern of the Lake Lugu sediments are distinct from those of adjacent geographical areas, but are shown to overlap with the sediments from the Kashmir Valley and northwestern (NW) Deccan Plateau indicating a long-distance dust source. The grain-size endmember for the aeolian deposits shows a gradually increasing trend from 32 kyr B.P. to the onset of the Holocene, followed by a sharp decrease around 9 kyr B.P., with very low values observed during the Holocene optimum (8.3–2 kyr B.P.). Aeolian deposition resumed from 2 kyr B.P. and has continued to the present day. Comparisons with both local and regional palaeoclimate records show that both the local climate and East Asian monsoon (EAM) have not influenced aeolian deposition in Lake Lugu. Rather, changing vegetation cover in the north India and NW Deccan Plateau provided the sediment supply, with entrainment governed by variations in the Southern Winter Westerlies in the dry season (north India), and the South Asian summer monsoon (SASM) in the rainy season (NW Deccan Plateau).

The origin, development and expansion of prehistoric agriculture in East Asia have been widely investigated over the past two decades using archaeobotanical analysis from excavated Neolithic and Bronze Age sites. Research on prehistoric agriculture has predominantly focused in the valleys of the Yellow River and the Yangtze River. Agricultural development during the Neolithic and Bronze Age periods in the Yunnan-Guizhou Plateau of southwest China, an important passageway for human migration into Southeast Asia, still remains unclear. In this paper, based on macrofossil and microfossil analysis and radiocarbon dating at the Shilinggang site, we investigate plant subsistence strategies in the Nujiang River valley during the Bronze Age period. Combined with previous archaeobotanical studies in the Yunnan-Guizhou Plateau, we explore agricultural development processes in this area during the Neolithic and Bronze Age. Our results indicate that rice and foxtail millet were cultivated in Shilinggang around 2500 cal a BP. Three phases of prehistoric agricultural development in the Yunnan-Guizhou Plateau can be identified: rice cultivation from 4800–3900 cal a BP, mixed rice and millet crop (foxtail millet and broomcorn millet) cultivation from 3900–3400 cal a BP, and mixed rice, millet crop and wheat cultivation from 3400–2300 cal a BP. The development of agriculture in the Yunnan-Guizhou Plateau during the Neolithic and Bronze Age periods was primarily promoted by prehistoric agriculture expansion across Eurasia, agricultural expansion which was also affected by the topographic and hydrological characteristics of the area.

The permanent human settlement of the Tibetan Plateau (TP) has been suggested to have been facilitated by the introduction of barley agriculture ∼3.6 kilo-years ago (ka). However, how barley agriculture spread onto the TP remains unknown. Given that the lower altitudes in the northeastern TP were occupied by millet cultivators from 5.2 ka, who also adopted barley farming ∼4 ka, it is highly possible that it was millet farmers who brought barley agriculture onto the TP ∼3.6 ka. To test this hypothesis, we analyzed mitochondrial DNA (mtDNA) from 8277 Tibetans and 58 514 individuals from surrounding populations, including 682 newly sequenced whole mitogenomes. Multiple lines of evidence, together with radiocarbon dating of cereal remains at different elevations, supports the scenario that two haplogroups (M9a1a1c1b1a and A11a1a), which are common in contemporary Tibetans (20.9%) and were probably even more common (40–50%) in early Tibetans prior to historical immigrations to the TP, represent the genetic legacy of the Neolithic millet farmers. Both haplogroups originated in northern China between 10.0–6.0 ka and differentiated in the ancestors of modern Tibetans ∼5.2–4.0 ka, matching the dispersal history of millet farming. By showing that substantial genetic components in contemporary Tibetans can trace their ancestry back to the Neolithic millet farmers, our study reveals that millet farmers adopted and brought barley agriculture to the TP ∼3.6–3.3 ka, and made an important contribution to the Tibetan gene pool.

Guedes et al. have drawn attention to a mismatch between the predictions of their "thermal niche model" and the records we have published of early barley finds in the northeastern Tibetan Plateau. Here, we consider how that mismatch usefully draws our attention to the additional variables that may account for it-namely, variations in genetic expression and agricultural practice.

In this essay, in the view of the ground grid corrosion problem, we establish a theoretical calculation model and engineering application model based on the way changing the current injection position and multiple measuring at each position. Finally, proposing a corresponding optimization algorithm on the basis of analyzing the characteristics of the problem. There are too many redundant equations (inequality group) when we establish the model by using the method of changing the current injection position and multiple measuring at each position. We remove those redundant equations (inequality group) by using great linearly independent groups corresponding to the initial feasible solution. But the the initial feasible solution is not easy to find, we apply least square method to solve the problem. Simulation shows that the model is correct, the method is valid.

We design a system of multiplex data acquisition, this acquisition system required not only to be run in high precision magnitude, but also to be capable of restraining power frequency interference for the case of complex application environment complex. In this paper, the advanced high-precision Σ-ΔA/D converter was introduced to be the front end of the 24bits data acquisition system and the π-type RC filter and Sinc3-type FIR notch filter were applied to restrain the power frequency interference. Simultaneously the USB2.0 bus technology was adopted with the EZ-USB FX2 controller to control A/D converter to transmit data to the upper computer for further analyzing. In the application of Corrosion Diagnosis for transformer substation Ground Grid, lab experiments and the field tests are to prove that this system can effectively restrain 50 Hz power frequency interference.

Guedes et al . have drawn attention to a mismatch between the predictions of their “thermal niche model” and the records we have published of early barley finds in the northeastern Tibetan Plateau. Here, we consider how that mismatch usefully draws our attention to the additional variables that may account for it—namely, variations in genetic expression and agricultural practice.