TY - JOUR A1 - Zhang, Wanyi A1 - Mischke, Steffen A1 - Zhang, Chengjun A1 - Gao, Dou A1 - Fan, Rong T1 - Ostracod distribution and habitat relationships in the Kunlun Mountains, northern Tibetan Plateau JF - Quaternary international : the journal of the International Union for Quaternary Research N2 - Surface sediment samples were collected from the lakes Heihai, Kusai, Haiding Nuur and Yan Hu, and from streams and ponds in the Kunlun Mountains at the northern margin of the Tibetan Plateau to investigate the sub-fossil ostracod (micro-crustacean) fauna of the region. Among 65 collected samples, 46 ostracod shell-rich samples were used to study the relationship between the ostracod distribution and specific conductivity (SC) of the water, which ranged from 0.6 to 53.0 mS cm(-1). A total of eleven ostracod species was identified from this region, with about half of the species restricted to the Tibetan Plateau and its adjacent mountain areas, and the other half representing Holarctic taxa. Tonnacypris cf. estonica and Tonnacypris tonnensis are reported from the Tibetan Plateau for the first time. Leucocythere sp. is the dominant species and Ilyocypris cf. bradyi is also relatively abundant. The other seven species were recorded with limited abundances apparently due to lower SC tolerances. Leucocythere sp. was recorded over the full SC range from 0.6 to 53 mS cm(-1). Eucypris mareotica is a typical brackish and saline water species, which was found at sample sites with high SC (2.8-53.0 mS cm(-1)). In contrast, Leucocythere dorsotuberosa, Candona candida and Eucypris afghanistanensis prefer freshwater to slightly oli-gohaline waters with SC < 1.8 mS cm(-1). The SC optimum and tolerance range for each species were determined and compared to earlier reported data from other regions of Central Asia. The results indicate that species assemblage data from fossil ostracod shells have a large potential to provide information on past SC levels and more general climate-determined moisture conditions. (C) 2013 Elsevier Ltd and INQUA. All rights reserved. Y1 - 2013 U6 - https://doi.org/10.1016/j.quaint.2013.06.020 SN - 1040-6182 VL - 313 SP - 38 EP - 46 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zhang Chengjun, A1 - Fan Rong, A1 - Li Jun, A1 - Mischke, Steffen A1 - Dembele, Blaise A1 - Hu Xiaolan, T1 - Carbon and oxygen isotopic compositions - how lacustrine environmental factors respond in northwestern and northeastern China JF - Acta geologica Sinica : english edition N2 - Surface lake sediments, 28 from Hoh Xil, 24 from northeastern China, 99 from Lake Bosten, 31 from Ulungur and 26 from Heihai were collected to determine C-13 and O-18 values. Considering the impact factors, conductivity, alkalinity, pH, TOC, C/N and carbonate-content in the sediments, Cl, P, S, and metal element ratios of Mg/Ca, Sr/Ca, Fe/Mn of bulk sediments as environmental variables enable evaluation of their influences on C-13 and O-18 using principal component analysis (PCA) method. The closure and residence time of lakes can influence the correlation between C-13 and O-18. Lake water will change from fresh to brackish with increasing reduction and eutrophication effects. Mg/Ca in the bulk sediment indicates the characteristic of residence time, Sr/Ca and Fe/Mn infer the salinity of lakes. Carbonate formation processes and types can influence the C-13-O-18 correlation. O-18 will be heavier from Mg-calcite and aragonite formed in a high-salinity water body than calcite formed in freshwater conditions. When carbonate content is less than 30%, there is no relationship with either C-13 or O-18, and also none between C-13 and O-18. More than 30%, carbonate content, however, co-varies highly to C-13 and O-18, and there is also a high correlation between C-13 and O-18. Vegetation conditions and primary productivity of lakes can influence the characteristics of C-13 and O-18, and their co-variance. Total organic matter content (TOC) in the sediments is higher with more terrestrial and submerged plants infilling. In northeastern and northwestern China, when organic matter in the lake sediments comes from endogenous floating organisms and algae, the C-13 value is high. C-13 is in the range of -4%o to 0 parts per thousand when organic matter comes mainly from floating organisms (C/N<6); in the range of -4 parts per thousand to 8 parts per thousand when organic matter comes from diatoms (C/N=6 to 8); and -8 parts per thousand to -4 parts per thousand when organic matter comes from aquatic and terrestrial plants (C/N>8). KW - Limnology KW - isotopic analysis KW - carbonates KW - organic matter KW - PCA KW - Tibet KW - Xinjiang KW - Northeastern China Y1 - 2013 U6 - https://doi.org/10.1111/1755-6724.12133 SN - 1000-9515 SN - 1755-6724 VL - 87 IS - 5 SP - 1344 EP - 1354 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Ramisch, Arne A1 - Lockot, Gregori A1 - Haberzettl, Torsten A1 - Hartmann, Kai A1 - Kuhn, Gerhard A1 - Lehmkuhl, Frank A1 - Schimpf, Stefan A1 - Schulte, Philipp A1 - Stauch, Georg A1 - Wang, Rong A1 - Wunnemann, Bernd A1 - Yan, Dada A1 - Zhang, Yongzhan A1 - Diekmann, Bernhard T1 - A persistent northern boundary of Indian Summer Monsoon precipitation over Central Asia during the Holocene JF - Scientific reports N2 - Extra-tropical circulation systems impede poleward moisture advection by the Indian Summer Monsoon. In this context, the Himalayan range is believed to insulate the south Asian circulation from extra-tropical influences and to delineate the northern extent of the Indian Summer Monsoon in central Asia. Paleoclimatic evidence, however, suggests increased moisture availability in the Early Holocene north of the Himalayan range which is attributed to an intensification of the Indian Summer Monsoon. Nevertheless, mechanisms leading to a surpassing of the Himalayan range and the northern maximum extent of summer monsoonal influence remain unknown. Here we show that the Kunlun barrier on the northern Tibetan Plateau [similar to 36 degrees N] delimits Indian Summer Monsoon precipitation during the Holocene. The presence of the barrier relocates the insulation effect 1,000 km further north, allowing a continental low intensity branch of the Indian Summer Monsoon which is persistent throughout the Holocene. Precipitation intensities at its northern extent seem to be driven by differentiated solar heating of the Northern Hemisphere indicating dependency on energy-gradients rather than absolute radiation intensities. The identified spatial constraints of monsoonal precipitation will facilitate the prediction of future monsoonal precipitation patterns in Central Asia under varying climatic conditions. Y1 - 2016 U6 - https://doi.org/10.1038/srep25791 SN - 2045-2322 VL - 6 SP - 596 EP - 633 PB - Nature Publ. Group CY - London ER - TY - GEN A1 - Mischke, Steffen A1 - Zhang, Chengjun A1 - Fan, Rong T1 - Early to mid-Holocene lake high-stand sediments at Lake Donggi Cona, northeastern Tibetan Plateau, China - T2 - Quaternary research : an interdisciplinary journal KW - Microfossils KW - Ostracoda KW - Lake level KW - Wetlands KW - Depositional setting KW - Tibetan Plateau KW - Holocene Y1 - 2015 U6 - https://doi.org/10.1016/j.yqres.2014.06.005 SN - 0033-5894 SN - 1096-0287 VL - 83 IS - 1 SP - 256 EP - 258 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Deusdará-Leal, Karinne A1 - Samprogna Mohor, Guilherme A1 - Cuartas, Luz Adriana A1 - Seluchi, Marcelo E. A1 - Marengo, Jose A. A1 - Zhang, Rong A1 - Broedel, Elisangela A1 - Amore, Diogo de Jesus A1 - Alvalá, Regina C. S. A1 - Cunha, Ana Paula M. A. A1 - Gonçalves, José A. C. T1 - Trends and climate elasticity of streamflow in south-eastern Brazil basins JF - Water N2 - Trends in streamflow, rainfall and potential evapotranspiration (PET) time series, from 1970 to 2017, were assessed for five important hydrological basins in Southeastern Brazil. The concept of elasticity was also used to assess the streamflow sensitivity to changes in climate variables, for annual data and 5-, 10- and 20-year moving averages. Significant negative trends in streamflow and rainfall and significant increasing trend in PET were detected. For annual analysis, elasticity revealed that 1% decrease in rainfall resulted in 1.21-2.19% decrease in streamflow, while 1% increase in PET induced different reductions percentages in streamflow, ranging from 2.45% to 9.67%. When both PET and rainfall were computed to calculate the elasticity, results were positive for some basins. Elasticity analysis considering 20-year moving averages revealed that impacts on the streamflow were cumulative: 1% decrease in rainfall resulted in 1.83-4.75% decrease in streamflow, while 1% increase in PET induced 3.47-28.3% decrease in streamflow. This different temporal response may be associated with the hydrological memory of the basins. Streamflow appears to be more sensitive in less rainy basins. This study provides useful information to support strategic government decisions, especially when the security of water resources and drought mitigation are considered in face of climate change. KW - runoff KW - precipitation KW - potential evapotranspiration KW - Pettitt test KW - sensitivity Y1 - 2022 U6 - https://doi.org/10.3390/w14142245 SN - 2073-4441 VL - 14 IS - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - Wang, Rong A1 - Biskaborn, Boris A1 - Ramisch, Arne A1 - Ren, Jian A1 - Zhang, Yongzhan A1 - Gersonde, Rainer A1 - Diekmann, Bernhard T1 - Modern modes of provenance and dispersal of terrigenous sediments in the North Pacific and Bering Sea: implications and perspectives for palaeoenvironmental reconstructions JF - Geo-marine letters : an international journal of marine geology N2 - During expedition 202 aboard the RV Sonne in 2009, 39 seafloor surface sediment sites were sampled over a wide sector of the North Pacific and adjoining Bering Sea. The data served to infer land-ocean linkages of terrigenous sediment supply in terms of major sources and modes of sediment transport within an over-regional context. This is based on an integrated approach dealing with grain-size analysis, bulk mineralogy and clay mineralogy in combination with statistical data evaluation (end-member modelling of grain-size data, fuzzy cluster analysis of mineralogical data). The findings on clay mineralogy served to update those of earlier work extracted from the literature. Today, two processes of terrigenous sediment supply prevail in the study area: far-distance aeolian sediment supply to the pelagic North Pacific, and hemipelagic sediment dispersal from nearby land sources via ocean currents along the continental margins and island arcs. Aeolian particles show the finest grain sizes (clay and fine silt), whereas hemipelagic sediments have high abundances of coarse silt. Exposed sites on seamounts and the continental slope are partly swept by strong currents, leading to residual enrichment of fine sand. Four sediment sources can be distinguished on the basis of distinct index minerals revealed by statistical data analysis: dust plumes from central Asia (quartz, illite), altered materials from the volcanic regions of Kamchatka and the Aleutian Arc (smectite), detritus from the Alaskan Cordillera (chlorite, hornblende), and fluvial detritus from far-eastern Siberia and the Alaska mainland (quartz, feldspar, illite). These findings confirm those of former studies but considerably expand the geographic range of this suite of proxies as far south as 39A degrees N in the open North Pacific. The present integrated methodological approach proved useful in identifying the major modern processes of terrigenous sediment supply to the study region. This aspect deserves attention in the selection of sediment core sites for future palaeoenvironmental reconstructions related to aeolian and glacial dynamics, as well as the recognition of palaeo-ocean circulation patterns in general. Y1 - 2016 U6 - https://doi.org/10.1007/s00367-016-0445-7 SN - 0276-0460 SN - 1432-1157 VL - 36 SP - 259 EP - 270 PB - Springer CY - New York ER - TY - JOUR A1 - Wang, Rong A1 - Zhang, Yongzhan A1 - Wünnemann, Bernd A1 - Biskaborn, Boris A1 - Yin, He A1 - Xia, Fei A1 - Zhou, Lianfu A1 - Diekmann, Bernhard T1 - Linkages between Quaternary climate change and sedimentary processes in Hala Lake, northern Tibetan Plateau, China JF - Journal of Asian earth sciences N2 - Profundal lake sediment cores are often interpreted in line with diverse and detailed sedimentological processes to infer paleoenvironmental conditions. The effects of frozen lake surfaces on terrigenous sediment deposition and how climate changes on the Tibetan Plateau are reflected in these lakes, however, is seldom discussed. A lake sediment core from Hala Lake (590 km(2)), northeastern Tibetan Plateau spanning the time interval from the Last Glacial Maximum to the present was investigated using high-resolution grain-size composition of lacustrine deposits. Seismic analysis along a north-south profile across the lake was used to infer the sedimentary setting within the lake basin. Periods of freezing and melting processes on the lake surface were identified by MODIS (MOD10A1) satellite data. End-member modeling of the grain size distribution allowed the discrimination between lacustrine, eolian and fluvial sediments. The dominant clay sedimentation (slack water type) during the global Last Glacial Maximum (LGM) reflects ice interceptions in long cold periods, in contrast to abundant eolian input during abrupt cold events. Therefore, fluvial and slack water sedimentation processes can indicate changes in the local paleoclimate during periods of the lake being frozen, when eolian input was minor. Inferred warm (i.e., similar to 22.7 and 19.5 cal. ka BP) and cold (i.e., similar to 11-9 and 3-1.5 cal. ka BP) spells have significant environmental impacts, not only in the regional realm, but they are also coherent with global-scale climate events. The eolian input generally follows the trend of the mid-latitude westerly wind dynamics in winter, contributing medium-sized sand to the lake center, deposited within the ice cover during icing and melting phases. Enhanced input was dominant during the Younger Dryas, Heinrich Event 1 and at around 8.2 ka, equivalent to the well-known events of the North Atlantic realm. (C) 2015 Elsevier Ltd. All rights reserved. KW - Tibetan Plateau KW - Lake deposits KW - End-member modeling KW - Grain size KW - Pleistocene and Holocene climate Y1 - 2015 U6 - https://doi.org/10.1016/j.jseaes.2015.04.008 SN - 1367-9120 SN - 1878-5786 VL - 107 SP - 140 EP - 150 PB - Elsevier CY - Oxford ER -