Bacterial community in cold and alkaline environments of Hoh Xil basin in Qinghai–Tibet Plateau and isolation of potential sources of microbiota

The Hoh Xil basin is the largest Cenozoic sedimentary basin in the Qinghai–Tibet Plateau (QTP) with an average altitude of above 5000 m. It is also the coldest region in the QTP. However, due to the difficulty of sample collection caused by the harsh natural environment, a limited number of studies have been conducted on soil microorganisms in this region. We used culture-dependent and independent methods to investigate the bacterial communities in desert soil (n1), saline–alkali land (n2), saline–alkali wetland (n3), and soda lake sediment (n4). The results showed distinct bacterial communities between different environmental types. We found that the Chao1 and Shannon diversity indices of n1 were significantly lower than those of n4 (P < 0.05). At the phylum level, all samples were dominated by representatives of Proteobacteria, Bacteroidetes, and Actinobacteria, which were similar to the findings of previous studies on the desert soil in the same region. Moreover, we identified 10 strains of bacteria from 109 isolates, most of which belonged to Pseudomonas (90.8%). The growth of the isolate k9 was optimal at a high pH value (pH 10.0) and a low temperature (5 °C), and this stain could produce extracellular enzyme (alkaline phosphatase, acid phosphatase, and naphthol-AS-BI-phosphohydrolase) under alkaline (pH 10) and cold (5 °C) condition. These results demonstrate the diversity of bacteria in the Hoh Xil basin and identify potential psychrophilic and alkaliphilic bacteria with multiple types of extracellular enzyme activity.     

Miocene pollen record of KC-1 core in the Qaidam Basin,NE Tibetan Plateau and implications for evolution of the East Asian monsoon

Thick Cenozoic deposits in the Qaidam Basin provide great potential for understanding the tectonic history, paleoclimatic changes, and evolution of the East Asian Monsoon. This study examines the pollen record from the KC-1 core for the interval covering the later Early to Late Miocene (18–5 Ma). Thermophilic taxa percentages are high between 18 and 14 Ma and decrease after this time, a pattern which fits well with the Middle Miocene Climatic Optimum (MMCO) between 18 and 14 Ma and global climatic cooling after 14 Ma. During the same period, xerophytic taxa percentages gradually increase and those of the conifers gradually decrease, suggesting an aridification process in the Qaidam region driven by the gradual strengthening of the East Asian winter monsoon (EAWM) and weakening of the East Asian summer monsoon (EASM). The global climate cooling process appears to have driven the climatic development of the Qaidam Basin region throughout the Miocene, but the uplift of the Tibetan Plateau also contributed.     

羌塘、可可西里无人区野牦牛种群数量和分布现状

野牦牛(Bos grunniens)是青藏高原特有的大型有蹄类动物, 主要分布在西藏羌塘, 青海可可西里、三江源, 新疆阿尔金山等地的高海拔生境。我们于2012-2014年在西藏羌塘和青海可可西里对野牦牛进行了较为全面的实地调查, 并且估算西藏羌塘地区野牦牛种群在11,222-21,072头之间, 可可西里野牦牛种群数量在659-1,793头之间。据本次野外调查和历史文献资料显示, 自20世纪90年代起, 中国野牦牛种群数量逐年增长, 但是其分布区面积却逐步缩减, 目前仅分布在几个相对孤立且远离人类居住地的高寒区域。随着全球气候变化与青藏高原人类活动的加强,野牦牛的生存现状依然严峻, 我们仍需加强对青藏高原特有物种的保护。     

滇东南普阳盆地含煤地层孢粉组合特征及其年代

云南地处青藏高原东南缘, 生物多样性丰富, 季风气候特征明显。新生代剧烈的构造活动形成了众多山间盆地, 其间保存了大量精美的植物化石, 是探讨新生代以来植被、植物多样性和地球环境演变的理想地区。但是长期以来, 由于地层年代学证据的缺乏, 这些新生代沉积盆地的地质年代还存在很大争议。本研究通过对滇东南地区富宁县普阳盆地的含煤地层开展深入的孢粉学研究, 探讨盆地含煤地层年代及其古气候演化过程。剖面下部煤层孢粉组合以杉粉属(Taxodiaceaepollenites)为主, 指示以杉科为主的湿润沼泽森林, 冬春季相对湿润; 剖面上部孢粉组合指示以常绿栎类为主的亚热带常绿‒落叶阔叶混交林, 生长山核桃粉属(Caryapollenites)、冬青粉属(Ilexpollenites)、胡桃粉属(Juglanspollenites)、枫香粉属(Liquidambarpollenites)等亚热带常见树种, 气候温暖湿润, 季节分明。结合新发现的哺乳动物化石证据和周边地区不同地质时代的孢粉组合, 普阳盆地含煤地层的沉积时代应为晚始新世; 同时, 孢粉组合也表明滇东南地区植被现代化面貌至少在晚始新世就已经开始出现。     

柴达木盆地宗马海湖地区始新统下干柴沟组 轮藻植物群

柴达木盆地北缘宗马海湖地区始新统下干柴沟组在一道沟剖面出露良好, 本文详细描述了该剖面下干柴沟组的岩性特征, 该组以棕红色泥岩为主, 局部夹浅灰绿色含石膏中细砂岩、含钙质粉砂质细砂岩及少量含砾中粗砂岩、褐红色灰岩。在该剖面发现轮藻化石2属2种: Lamprothamnium ganchaigouensis (Tang and Di) Li et al. comb. nov.和Lychnothamnus vectensis (Groves) Soulié-M?rsche, 前者为新联合属种。L. vectensis主要发现于欧洲始新统?渐新统, 在我国始新统系首次报道。本文以居群为单位, 讨论了L. vectensis的种内形态变化, 包括藏卵器尺寸和顶部装饰的连续变化。欧洲L. vectensis居群的藏卵器尺寸随着纬度的升高有变大的趋势, 而柴达木盆地的纬度低于欧洲埃布罗盆地和巴黎盆地的纬度, 它所产的L. vectensis居群藏卵器尺寸却更大, 推测与柴达木盆地古湖泊水体清澈度和/或温度更高相关。     

Paleogene terrigenous (flysch) sequences in Etoloakarnania region (W. Greece). Plankton stratigraphy and paleoenvironmental implications

Based on calcareous nannofossils and planktonic foraminifera1 biostratigraphic data from flysch sequences, we give evidence for the paleoenvironmental evolution of Gavrovo and Ionian foreland basins (External Hellenides, Etoloakarnania region). Our data suggest that the onset of clastic sedimentation in both foreland basins in the study area is chronostratigraphically placed at Late Eocene (from 36.2-34.4 Ma; nannofossil biozones NP19-20, planktonic foraminifera biozones P16-17). During the earliest Oligocene (NP21-22 nannofossil biozones/34.4-32.45 Ma), both basins represent restricted accumulation of sediments, mainly composed of clays and silts. The presence of thick flysch deposits, accumulated during Early Oligocene (33.4-30 Ma, nannofossil zone NP23), indicates an increasing rate of sediment supply. The flysch sequences in the Ionian basin are associated with a distal depositional environment, while in the same time the sedimentation in the external part of Gavrovo basin is related to a more proximal environment that is gradually deepening. On the contrary, the internal part of Gavrovo basin is characterised by deep-water facies, deposited in the Early Oligocene. At the end of Early Oligocene and the onset of Late Oligocene (nannofossil zone NP24/30-27.2 Ma, planktonic foraminifera zone P21), the deposition of coarse grained sediments in both basins indicates a shift to shallower depositional environment. The accumulation of fine-grained sediments during Late Oligocene (27.2-23.2 Ma, NP25 nannofossil biozone) in the Ionian basin marks the youngest flysch sediments in the Etoloakarnania region and specifies the time of the Gavrovo nappe emplacement on the Ionian zone. Moreover the emplacement of Pindos nappe on the Gavrovo zone is estimated between 30-27.2 Ma (NP24 biozone) as supported by the nannofossil analysis of samples in front of Pindos thrust.     

Uplift of the Ou Backbone Range in Northeast Japan at around 10 Ma and its implication for the tectonic evolution of the eastern margin of Asia

The Late Cenozoic uplift history of a sedimentary basin located in the axial part of the Ou Backbone Range, Northeast Japan, was studied using detailed mapping, fission-track dating and basin analysis. The subsidence analysis of the basin clarified the more complex stepwise uplift of the Ou Backbone Range. Three stages of uplift have been recognized and are interpreted to be the result of compressional stress, possibly accompanied by basin inversion. The three stages are identified as (1) a phase of surface uplift and regional unconformity (12-9 Ma), (2) a stage of differential uplift and compression (6.5-3 Ma) and (3) an intense compression stage (∼ 3 Ma). In the first stage, the eastern sector of the Backbone Range uplifted and a notable unconformity was formed at ∼ 10 Ma. The western sector remained submerged, suggesting that the eastern sector uplifted earlier than the western sector. Although the first uplift stage has been regarded as a tectonically quiet period in Northeast Japan, this tectonic event at ∼ 10 Ma is supposed to have a regional origin because coeval tectonic events took place across all Northeast Japan, as well as on the eastern margin of Asia. This study thus provides new insights into the Neogene tectonic evolution in the eastern margin of Asia.     

Biostratigraphy and sedimentary evolution of Late Miocene and Pliocene continental deposits of the Granada Basin (southern Spain)

The Late Miocene and Pliocene continental sediments in the Granada Basin (southern Spain) have yielded large amounts of fossil small mammals in 37 localities from 11 sections. The aim of this paper is to integrate faunistic, stratigraphic, and sedimentary criteria to unravel the geological history of the continental infilling of the basin. The palaeontological study has led to a detailed biozonation on the basis of rodents, which helps to correlate in detail the different sedimentary units found in the basin, and to follow the changes of the different sedimentary systems and their palaeogeographical evolution through time. Combination of the proposed biostratigraphy and the reinterpretation of the magnetostratigraphic analyses of the Barranco del Purcal section allows us to assign an absolute age slightly older than 5.23 Ma to the Turolian–Ruscinian boundary (MN13‐MN14).     

2003—2020年青藏高原冻融侵蚀时空变化特征

全球气候变暖导致青藏高原永久冻土逐渐退化,并增加了季节性冻土的面积,但对冻融侵蚀时空变化还缺乏系统的认识。通过权重法对年冻融日循环天数、日冻融相变水量、植被覆盖度、年均降雨量、坡度和坡向6个冻融侵蚀因子进行赋权,分析青藏高原2003—2020年不同强度的冻融侵蚀时空变化和主导驱动因素。结果表明：(1)2003—2020年青藏高原平均冻融侵蚀面积为(161.37±0.42)×10⁴km²,占青藏高原面积的64.55%,中度及以上侵蚀占冻融侵蚀面积的63.0%,强烈、极强烈和剧烈侵蚀主要分布在雅鲁藏布江流域、昆仑山-祁连山、帕米尔高原地区;(2)2003—2020年青藏高原冻融侵蚀表现为加剧趋势,加剧的区域达到29.79×10⁴km²,占青藏高原面积的11.6%;2003—2010年中度及以上平均侵蚀面积为(95.71±3.33)×10⁴ km²,2013—2020年为(107.60±3.20)×10⁴ km²,其面...     

基于线粒体 Cyt b 基因的柴达木盆地子午沙鼠的遗传多样性与种群结构分析

对采集自柴达木盆地4个子午沙鼠种群的线粒体Cyt b部分序列进行测序,分析其遗传多样性和种群间系统进化关系。结果显示：冷湖-苏干湖种群的遗传多样性最高（Hd = 1.000;π = 0.00530）,花土沟种群的遗传多样性最低（Hd = 0.750;π = 0.00255）。分子变异分析结果显示61.68%的变异来自种群内,38.32%的变异来自种群间。其中, 冷湖-苏干湖种群与其他种群之间的遗传分化水平相对较低,格尔木种群与其他种群之间有较高水平的遗传分化。系统进化分析显示柴达木盆地子午沙鼠以冷湖-苏干湖为发源地沿盆地周边自西向东扩散,各种群之间存在广泛的基因交流。由于地理阻隔,格尔木种群与其他种群间基因交流较少。各地理种群间遗传距离与地理距离不相关。青藏高原大湖期是柴达木盆地各种群之间产生遗传分化的主要原因。     

New material of Muntiacinae (Artiodactyla,Mammalia) from the Late Miocene of the northeastern Qinghai-Tibetan Plateau,China

Recent expeditions in the northeastern Qinghai-Tibetan Plateau have produced additional mammalian fossils from the Lower Baodean (equivalent to Vallesian, Late Miocene), and, significantly, a new large and the earliest muntjac, Muntiacus noringenensis sp. nov. It is phylogenetically closer to the Late Pliocene M. fenghoensis and extant M. vuqangensis than the other fossil and extant muntjacs are. The existence of this muntjac and other folivores in the Late Miocene Qaidam Basin suggests a forested period in the basin and the evolution from a forested and humid environment to a desert one today. Such a dramatic evolution in environments is an evidence of the effect of the uplift of the Qinghai-Tibetan Plateau and of its influence on continental climates.     

Middle and Late Triassic radiolarians from northern Tibet: Implications for the Bayan Har Basin evolution

During the Triassic, the Bayan Har Basin is a huge triangular basin surrounded by the North China Platform, South China Platform and Qingtang Terrane. It is filled by a Triassic turbidite sequence, the Bayan Har Group. For a long time, the series of Bayan Har Group in the eastern part of the basin were considered to be a Lower to Upper Triassic sequence, and in the western part, was attributed to the Upper Triassic. A well-preserved diversified radiolarian fauna was recovered from radiolarian chert and tuffite interbeds of the Bayan Har Group turbidites and adjacent stratigraphic units in the Hoh Xil area, northern Tibet. Sixty-seven species are identified and subdivided into two assemblages: late Anisian and early Carnian. Combined with the discovery of the Late Permian and Early Triassic turbidite in the Bayan Har Group in this area by Huang et al., it proves that all the Triassic is also present in the Bayan Har Group sequence in the western part. The evolution of the Bayan Har Basin may be traced back to the Late Permian. The massive sequence of the Bayan Har Group and its provenance indicate that the Kunlun and Qinling orogenic belts rapidly rise during the Middle-Late Triassic. The basin extended to the end of the Triassic, possibly locally to the Jurassic.     

Palynological evidence for Late Miocene-Pliocene vegetation evolution recorded in the red clay sequence of the central Chinese Loess Plateau and implication for palaeoenvironmental change

In northern China, the Late Miocene-Pliocene red clay in the eastern Loess Plateau fills a gap of climate records between the well-known loess-soil sequences of the last 2.6 Ma and the Miocene loess-soil sequences from the western Loess Plateau. Previous studies indicate that the red clay is also of wind-blown origin, covering the period from ∼ 7-8 to ∼ 2.6 Ma. The red clay therefore provides a good archive to reconstruct paleoecological succession and paleoclimate change. In this study, a palynological investigation was conducted on the late Miocene-Pliocene red clay sequence at Xifeng, central Loess Plateau, which provides new insights into the nature of the evolution of vegetation and climate change from ∼ 6.2 to ∼ 2.4 Ma. Our results show that during this period the central Loess Plateau region was covered mainly by a steppe vegetation, indicating long lasting dry climatic condition. Three vegetational zones were recognized during this period. Zone A (∼ 6.2 to ∼ 5.8 Ma) is characterized by a steppe ecosystem; Zone B (∼ 5.8 to ∼ 4.2 Ma) is characterized by a significant increase of temperate forest plants, indicating a relatively humid regional climate; Zone C (∼ 4.2 to ∼ 2.4 Ma) indicates a typical steppe ecosystem. The vegetation shift at about 4.5-3.7 Ma, when the temperate forest plants decrease, the vegetation gradually changed to typical grassland and even to desert steppe. This is interpreted to represent a drying event. The uplift of the Tibetan Plateau at about 4.5 Ma that resulted in the intensification of the monsoon reversal is thought to have played an important role in this significant ecological change. High-latitude cooling may have partially contributed to the climate shift during ∼ 4.5 to ∼ 3.7 Ma in the Loess Plateau region, and most likely was the driving force for the ecological shift at about 3.7 Ma.     

Pleistocene rapid uplift of the Himalayan frontal ranges recorded in the Kathmandu and Siwalik basins

Core-drilling project carried out in the southern margin of the Kathmandu Basin revealed that muddy debris flow deposits dammed up the Proto-Bagmati river to form the Paleo-Kathmandu Lake during the Jaramillo subchron from 1.07 to 0.97 Ma. Subsequent deposition of the alluvial fanglomerate, derived from the uplifting Mahabharat Range to the south, raised the dam deepening the lake-water. After 1 Ma, in the southern part of the basin, palaeo-current directions changed from southward to northward and deposition of gneissose and granitic detritus are replaced by meta-sediments derived from the Mahabharat Range.During the same time, at about 1 Ma, the boulder conglomerates were deposited on top of the Siwalik Group as piggy-back basins in front of an intra-basinal high, along the Main Dung Thrust in Nepal and NW India. Onset of movement of the Main Dung Thrust is dated back to 3 to 2.4 Ma [Mugnier, J.L., Huyge, P., Leturmy, P., Jouanne, F., 2003, Episodicity and rates of thrust-sheet motion in the Himalayas, Western Nepal. Am. Assoc. Petrol. Geol., Mem. 82, 1-24]. The Main Frontal Thrust is most active at present suggesting that imbricated structure of the Siwalik Group was formed by convergence of the Indian plate during the last 3 myr. The accretionary wedge of the Siwalik Group, stacked beneath the Main Boundary Thrust, might have started to jack up the frontal range of the Lesser Himalaya since 1 Ma.Coeval uplift and erosion of the frontal range of the Lesser Himalaya and the intra-basinal high in the Siwalik since 1 Ma are possible causes of an abrupt increase in both sedimentation rate and grain size of detrital quartz, and changes in composition of clay minerals, recorded in the sediments of the Bengal Deep Sea Fan at 0.9 Ma.     

Continental impacts of water development on waterbirds,contrasting two Australian river basins: Global implications for sustainable water use

The world's freshwater biotas are declining in diversity, range and abundance, more than in other realms, with human appropriation of water. Despite considerable data on the distribution of dams and their hydrological effects on river systems, there are few expansive and long analyses of impacts on freshwater biota. We investigated trends in waterbird communities over 32 years, (1983–2014), at three spatial scales in two similarly sized large river basins, with contrasting levels of water resource development, representing almost a third (29%) of Australia: the Murray–Darling Basin and the Lake Eyre Basin. The Murray–Darling Basin is Australia's most developed river basin (240 dams storing 29,893 GL) while the Lake Eyre Basin is one of the less developed basins (1 dam storing 14 GL). We compared the long‐term responses of waterbird communities in the two river basins at river basin, catchment and major wetland scales. Waterbird abundances were strongly related to river flows and rainfall. For the developed Murray–Darling Basin, we identified significant long‐term declines in total abundances, functional response groups (e.g., piscivores) and individual species of waterbird (n = 50), associated with reductions in cumulative annual flow. These trends indicated ecosystem level changes. Contrastingly, we found no evidence of waterbird declines in the undeveloped Lake Eyre Basin. We also modelled the effects of the Australian Government buying up water rights and returning these to the riverine environment, at a substantial cost (>3.1 AUD billion) which were projected to partly (18% improvement) restore waterbird abundances, but projected climate change effects could reduce these benefits considerably to only a 1% or 4% improvement, with respective annual recovery of environmental flows of 2,800 GL or 3,200 GL. Our unique large temporal and spatial scale analyses demonstrated severe long‐term ecological impact of water resource development on prominent freshwater animals, with implications for global management of water resources.     

Évolution des environnements littoraux du bassin de Melilla-Nador (Nord-Est Maroc) au Messinien supérieur entre 6,0 et 5,77 Ma

This study of late Messinian deposits (E2 = TCC) from Melilla-Nador carbonate complex (Morocco) allowed us to characterize the environmental evolution between 6.0 and 5.77 Ma, which is a period considered as contemporaneous of the onset and development of the “messinian salinity crisis”. A statistical approach coupled together with classical petrographic study allows us to constrain the sedimentary dynamic of platforms and to propose deposition environment models. The Melilla-Nador platforms E2 deposits show a progressive continuous evolution of littoral environments in two major stages of available space creation and infill. The first stage corresponds to the build up of a reef complex between 6.0 and 5.85 Ma then the second stage, between 5.85 and 5.77 Ma, corresponds to the development of a mixed oolitic shallow ramp during the progressive infill of Melilla-Nador basin. The comparison with the Sorbas basin (Spain) TCC deposits exhibits a very close evolution of late Messinian littoral environments, which could be used as a correlation tool.     

基于BIOMOD的青海湖流域高原鼠兔分布模拟

随着统计模型及空间信息数据的不断发展和完善,物种分布模型已经成为全球变化背景下研究大尺度物种分布情况的重要工具。高原鼠兔(Ochotona curzoniae)是青藏高原特有的关键物种,在青藏高原生态系统中占有重要地位。通过采集高原鼠兔的分布点数据及环境变量数据,基于R语言中BIOMOD包中的7个模型对其在青海湖流域的分布进行了模拟。结果表明,高原鼠兔主要分布于青海湖西岸和北岸、天峻县周边及布哈河流域上游,影响高原鼠兔分布的主要环境因子为距道路距离、距居民点距离、最暖月最高气温、NDVI标准差、最冷季和最干季降水量。BIOMOD组合模型中,推进式回归树模型(GBM)和最大熵模型(MAXENT)的模拟效果最好,广义线性回归模型(GLM)结果较差。而优化后的结果显示,模拟结果的集成和筛选能有效提高模型的精度和效果。     

西藏改则盆地晚始新世康托组介形类动物群及地质意义

西藏改则盆地新生代陆相康托组地层发育,记录了青藏高原腹地始新世气候变化和隆升历史。本文通过对改则盆地中南部改则县嘎热村康托组剖面进行系统的采样和室内处理,获得363个介形类个体,共鉴定11属27种(包括1个未定种)。通过研究区介形类动物群的特征分子Heterocypris igneus及与东濮、渤海、华北、江汉等地区介形类动物群对比研究,认为康托组上部的沉积时代应为晚始新世。本文首次报道了改则盆地康托组的介形类动物群面貌,据介形类组合厘定了康托组沉积时代,为研究青藏高原腹地新生代地层提供了基础资料。     

黄土高原典型区植被冗亏

选择了黄土高原中部典型区——泾河流域为研究区域。采用Holdridge潜在蒸发方法计算出了泾河流域的气候干燥度指数,构建了遥感植被指数与气候干燥度指数之间的回归模型。通过该模型反衍出了泾河流域潜在植被指数,提出以该指数为基础的植被冗亏格局的评价新方法。通过该评价方法发现,在泾河流域西北部的大部分子流域的植被冗亏指数小于-0.2,植被亏缺较为严重;在自然环境较差的流域北部,植被冗亏指数介于-0.20到-0.10之间,植被亏缺较轻;而流域东南部山区的大部分子流域的植被冗亏指数介于-0.10到0.10之间,植被亏缺最轻。从植被冗亏的时间尺度上分析,植被亏缺主要发生在植被生长旺盛的6~9月份,其中农田植被亏缺最大,冗亏指数在7月份可达到-0.51;稀疏草原植被亏缺较小,其冗亏指数最小值在-0.18左右;森林植被的冗亏指数接近于0。     

Macrofauna communities in the Amundsen Basin, at the Morris Jesup Rise and at the Yermak Plateau (Eurasian Arctic Ocean)

Macrofaunal communities of the western Eurasian Arctic Ocean were studied along a transect from the North Pole, across the Amundsen Basin and Gakkel Ridge towards the Morris Jesup Rise and the Yermak Plateau. Samples were collected during autumn 1991, from depths of 560–4411 m, using a box corer. Macrofaunal species numbers varied from 1 to 11 per 0.02 m² in the basins approaching the Morris Jesup Rise and from 44 to 81 per 0.25 m² at the Yermak Plateau. Abundances increased from 1 to 31 per 0.02 m² in the basin and on the Morris Jesup Rise to 24–60 per 0.02 m² on the Yermak Plateau. Biomass was low in the basin and at the Morris Jesup Rise (0.5–68.9 mg per 0.02 m²) but increased to 116.64 mg per 0.02 m² at the Yermak Plateau. A total of 108 taxa were recorded. The results contradict the hypothesis that diversity decreases with increasing latitude, and the high species richness at low abundance at intermediate depths was comparable with that observed in Antarctic and tropical regions.