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• Ecosystem multifunctionality was higher in rhizosphere soils than in bulk soils. • Ecosystem multifunctionality was mainly determined by environmental factors. • C cycling and N cycling varied among microhabitat and macrohabitat types. The importance of plant and soil microbial diversity in sustaining ecological functions has attracted considerable attention. However, little is known about how these factors jointly affect the ability of an ecosystem to provide multiple ecological functions simultaneously (i.e., ecosystem multifunctionality [EMF]) in natural environments, especially in wetlands. Here, we collected rhizosphere soils, bulk soils, and sediments (microhabitats) from riverine, lacustrine, and palustrine wetland sites (macrohabitats) across the remote Tibetan Plateau. Plant diversity (taxonomic, phylogenetic, and functional) and soil bacterial diversity (taxonomic and phylogenetic) were determined. We also calculated EMF using 20 variables related to soil carbon cycling, nitrogen cycling, and plant productivity. The results showed that EMF was significantly higher in rhizosphere soils than in bulk soils, but no significant differences were detected among the macrohabitat types. A significant relationship between EMF and bacterial diversity was detected only in rhizosphere soils, and a positive relationship between EMF and plant diversity was found in riverine and lacustrine wetlands. Environmental factors (climate and edaphic properties), bacterial diversity, and plant diversity together explained 63.48% of the EMF variation. Path modeling revealed that the effects of macrohabitat and microhabitat on EMF were mediated mainly through edaphic properties and bacterial diversity, respectively. These results significantly advance our understanding of the patterns and drivers of EMF in wetlands and are also critical for predicting changes in wetland functions in response to biodiversity loss and anthropogenic activities. [ABSTRACT FROM AUTHOR]

The Mid-Pleistocene transition (MPT) was characterized not only by the transition of ice volume periodicities from 40 kyr to 100 kyr, but also by major changes in high latitude ice sheets, global sea level and CO 2 / ocean carbon storage after ∼900 ka, which had a major influence on the evolution of the East Asian summer monsoon (EASM). However, there are different views regarding the trend of East Asian summer monsoon precipitation during the MPT and its driving mechanism. Together with published paleomagnetic and 26Al/10Be isotopic chronologies, we used pollen analysis of the lacustrine sediments of a drill core to reconstruct the vegetation history of the Northeast Plain of China. The results demonstrate a pattern of vegetation succession from coniferous and broadleaved mixed forest dominated by Pinus to woodland-steppe during the MPT, indicating a change from a semi-humid to a semi-arid climate. Palynological records from the Liaodong Peninsula, North China Plain, and the Tibetan Plateau also indicate a drying climate during the MPT, which was related to the decreasing trend of EASM precipitation. We suggest that falling global sea level caused by the expansion of high-latitude ice sheets, and the resulting the exposure of continental shelves and the increased transport distance of oceanic water vapor to the continental interior, was the main cause of the reduction in EASM precipitation. The weakening of the Atlantic meridional overturning circulation and the southward movement of the Intertropical Convergence Zone in the tropical Pacific may have been additional causes of the decrease in EASM precipitation. • Vegetation history during the MPT in Northeast Plain of China was reconstructed. • A decreasing trend of EASM precipitation was revealed during the MPT. • Both global sea level and AMOC might play important roles in the reduction in EASM precipitation. [ABSTRACT FROM AUTHOR]

Abstract: Major ion concentrations were measured in lake water, river water, ground water, and rainfall water around the Lake Qinghai catchment. The dissolution of carbonate particles in dust has a strong impact on the chemical composition of rainfall as inferred from the Gibbs model and the ternary plots of the major ions. The chemical composition of the ground water can be divided into two groups, one influenced by river water and the other dominated by deeper aquifers. The chemical composition of lake water can be mainly ascribed to evaporation and crystallization. Total dissolved solid (TDS) of river waters during the wet periods is higher than during the dry periods. Calcium and bicarbonate are the dominant cations and anions of the river waters, and they have higher fractions during the wet periods than during the dry periods. Comparisons between (Mg2+ +Ca2+)/TZ+, (Mg2+ +Ca2+)/(Na+ +K+), HCO3 −/Na+, and Cl−/Na+ suggest that the chemical composition of the river waters is mainly controlled by carbonate weathering and that the carbonate weathering is much stronger during the wet periods than during the dry periods. Seasonal melting may be one of the important factors that influence the seasonal variations of water chemistry of the rivers. [Copyright &y& Elsevier]

The Eocene/Oligocene transition (EOT) was marked by a major environmental reorganization accompanied by an abrupt shift of the Earth system from "greenhouse" to "icehouse" conditions, which is well documented in marine sedimentary records. Although there are an increasing number of terrestrial records documenting this major climatic reorganization, high-resolution sedimentologic and petrographic evidence from terrestrial contexts is sparse, and the processes driving the EOT which affected the formation of continental detrital sediments are unclear. Here we present evidence from lithofacies, lithology, sediment color, and sediment grain size from a section in the northern part of the NE Tibetan Plateau (Tibetan Plateau), which spans the EOT. The results indicate that major changes in the grain size (coarsening), chromaticity a* (redness increasing), thick gypsum layers (disappearance), structural maturity (decreasing roundness and sorting), sediment compositional maturity (increasing content of lithic, feldspar and mafic minerals) of silt and sandstone occurred at ~33.8 Ma, which were considered to be a response to the EOT. The synchronous changes in sedimentological and petrological characteristics and weathering proxies in the Qaidam Basin (Qaidam Basin) and neighboring basins suggest that the climate-forced weakening of weathering and erosion may have been the direct cause of those proxy changes the direct cause of those proxy change. Global cooling is speculated to have been the first-order driving factor in regulating climatic evolution and weathering responses in the Qaidam Basin and even the Asian interior at the EOT. A conceptual model is presented which summarizes the mechanisms responsible for the observed changes in sedimentary characteristics across the EOT. Unlabelled Image • A >40–26 Ma sedimentologic and petrologic record of northwestern Qaidam Baisin. • The dramatic shifts of grain-size and sediment color occurred at ~33.8 Ma. • The structure and composition maturity of silt and sandstone changed at ~33.8 Ma. • Deterioration of sedimentary conditions attributes to a cooler and drier climate. • A weakening of weathering and erosion associated with Eocene/Oligocene transition. [ABSTRACT FROM AUTHOR]