Review of the 22nd National Conference on the Theoretical Study of Science Popularization in China and the International Forum on Science Communication towards 2020

The 22nd National Conference on the Theoretical Study of Science Popularization in China and the International Forum on Science Communication towards 2020 was organised by the China Research Institute for Science Popularization (CRISP) in Beijing from October 17 to October 18, 2015. Nearly 200 international and national delegates from scientific research institutions, colleges and universities, local associations for science and technology from eight countries including America, Canada, Sweden, Australia, New Zealand, India, Japan and Korea participated in the Conference

The role of sea-level rise, monsoonal discharge and the palaeo-landscape in the early Holocene evolution of the Pearl River delta, southern China

The early Holocene history of the Pearl River delta is reconstructed based on a series of sediment cores obtained from one of the main palaeo-valleys in the basin. Sedimentary and microfossil diatom analyses combined with radiocarbon dating provide new evidence for the interactions between sea-level rise, antecedent topography and sedimentary discharge changes within the deltaic basin since the last glacial. These new records show that river channels of last glacial age incised down to c. −40 m into an older (possibly MIS5 age) marine sequence which forms the floor of the deltaic basin and exists primarily at c. 10 m–15 m below present mean sea level. Rapid postglacial sea-level rise flooded the incised valleys by the beginning of the Holocene, and prior to c. 9000 cal. years BP, marine inundation was largely confined within these incised valleys. The confined available accommodation space of the incised valleys combined with strong monsoon-driven freshwater, high sediment discharge and a period of rapid rising sea level meant that sedimentation rates were exceptionally high. Towards c. 8000 cal. years BP as sea level rose to about −5 m, marine inundation spilled out of the incised valleys and the sea flooded the whole deltaic basin. As a result, the mouth of the Pearl River was forced to retreat to the apex of the deltaic basin, water salinity within the basin increased markedly as the previously confined system dispersed across the basin, and the sedimentation changed from fluvial dominated to tidal dominated. Sea level continued to rise, albeit at a much reduced rate between 8000 and 7000 cal. years BP, and deltaic sedimentation was concentrated around the apex area of the basin. During the last 7000 cal. years BP, the delta shoreline moved seawards, and the sedimentary processes changed gradually from tidal dominated to fluvial dominated

Holocene warming and evergreen/deciduous forest replacement across eastern China

International audienceCombined variations of insolation and ice sheet led to major global climatic and ecosystem changes between the Last Glacial Maximum (LGM) and the Holocene. However, little is known about effects of these changes on the alternating dominance of deciduous and evergreen vegetation in East Asia, particularly in the regions now dominated by evergreen broadleaved forest (EBLF) that forms a vast ecotonal zone between tropical and temperate belts. In this study, we have used two representative records in center of the EBLF distribution, associated with broader regional pollen data from eastern China, to reconstruct spatiotemporal biome changes over the last 22 ka. The results showed a dominance of deciduous broadleaved forest at the LGM in most mountainous regions of the subtropical zone, and the EBLF began to migrate and expand into the low latitude subtropical areas during the last deglaciation, particularly at ca.11.3 ka after the Younger Dryas. However, major biome replacement from deciduous to evergreen forest across eastern China did not occur until 8.1 ka, indicating an earlier forest replacement at sites in low latitude regions as compared to sites located further north or at higher mountains. Our evidence agrees well with quantitative climate reconstruction and simulations at local and regional scales, showing that forest transformed when thermal conditions reached relevant thresholds. Both simulated and reconstructed paleotemperatures are consistent with the early-to-middle Holocene being a key period when climatic thresholds (particularly winter and/or annual temperatures) gradually approached then exceeded bioclimatic constraints on EBLF recolonization. By contrast, the precipitation in most part of mountainous subtropical southeast China may not be a key constraint for evergreen/deciduous forest transformation since the last deglaciation. During the late Holocene, the reconstructed biome has shifted unstably, probably due to interactive effects of several regional-scale factors, including seasonal climate biases and major fluctuations in effective moisture associated with weakening of summer monsoon before the enhanced human interventions of the last 3000 years

A new biologic paleoaltimetry indicating Late Miocene rapid uplift of northern Tibet Plateau

The uplift of the Tibet Plateau (TP) during the Miocene is crucial to understanding the evolution of Asian monsoon regimes and alpine biodiversity. However, the northern Tibet Plateau (NTP) remains poorly investigated. We use pollen records of montane conifers (Tsuga, Podocarpus, Abies, and Picea) as a new paleoaltimetry to construct two parallel midrange paleoelevation sequences in the NTP at 1332 ± 189 m and 433 ± 189 m, respectively, during the Middle Miocene [~15 million years ago (Ma)]. Both midranges increased rapidly to 3685 ± 87 m in the Late Miocene (~11 Ma) in the east, and to 3589 ± 62 m at ~7 Ma in the west. Our estimated rises in the east and west parts of the NTP during 15 to 7 Ma, together with data from other TP regions, indicate that during the Late Miocene the entire plateau may have reached a high elevation close to that of today, with consequent impacts on atmospheric precipitation and alpine biodiversity.</p