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Major rivers with high sediment or water discharge act as natural integrators of surficial processes, including human activities within their drainage basins, and they are also the primary sources of terrestrial materials entering the ocean. The river‐derived materials flux entering the coastal oceans, however, has been strongly affected by anthropogenic activities. Recent studies related to human impacts on river sediment flux have mainly focused on qualitative descriptions. Here we present a quantitative assessment of human impacts on decrease in sediment flux from nine major Chinese rivers entering the western Pacific Ocean, including Changjiang (Yangtze), Huanghe (Yellow), Zhujiang (Pearl), Songhuajiang, Liaohe, Haihe, Huaihe, Qiantangjiang, and Minjiang. During 1959–2007, dams and reservoirs, soil and water conservation programs, water consumption, as well as sand mining decreased the amount of sediment delivered to the ocean by 28, 11.5, 7.5 and 3 gigatons (Gt), respectively. If combined (50 Gt for the period 1959–2007), this reduction was close to the total decreased sediment flux (43 Gt) measured from these nine major rivers over the same period. Besides, the temporal variations in water and sediment fluxes into the ocean from these rivers generally during 1953–2007 were presented. These results are useful for further studies on Chinese and even global river‐derived material flux to the ocean and associated ecological risks.

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Pumice is the most widely distributed magmatic rock in the Okinawa Trough. Numerous scholars have conducted extensive research on the mineralogy, petrochemistry and whole‐rock isotopic characteristics of pumice. However, even with extensive research, some information about pumice is still unknown, including the initial provenance of magma, influences from subducting plates and the possibility of crustal material (including sediments) mixing in during pumice formation. As pumice is loose and porous, seawater re‐modification and injection of sediments may occur during the condensation and rock‐forming process after magma erupts from the seafloor, or in the seawater immersion process after pumice formation. In order to get a better understanding of the isotopic characteristics of magmatism phase, phenocrysts were first separated from the pumice and divided into both light and heavy minerals to analyse their Sr–Nd–Pb isotopic composition. This information was combined with existing isotopic data of volcanic rocks from the Okinawa Trough and its adjacent areas to assess the magma source composition, influence from subduction components and mantle properties in the magmatic source. The research results indicated light minerals had an average 87Sr/86Sr ratio of 0.70454, while heavy minerals averaged 0.70546. The magma, formed pumice, was a product of the crystal fractionation evolution of basic magma, with the additional injection of crustal material. The magma source in the central trough is a mixture of depleted MORB mantle (DMM) and enriched mantle (EMI‐like and EMII‐like) end members, where the EMI‐like end member is the residual subcontinental lithosphere or lower crustal material and the EMII‐like end member is subducted oceanic sediments. The Pb isotopic composition indicated that the magma source was affected by subduction components (sediments) and that pumice magma was mixed with more sediment than basalt magma material in the same area. The mantle of the magma source in the Okinawa Trough showed signatures of the Indian Ocean‐type mantle. Copyright © 2016 John Wiley & Sons, Ltd.

A ratiometric optical sensor has been developed with electrospinning processing method for dissolved oxygen measurement. The sensing film is fabricated by using silver nano-particles (Ag NPs) doped with tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) dichloride complex (Ru(DPP)3Cl2) encapsulated in plasticized polymethyl methacrylate (PMMA). An insensitive 3-(2-benzothiazolyl)-7-(diethy lamino)-(6CI,7CI) (Coumarin6) is adopted as reference. The ratio of oxygenation is calculated at each image pixel of a 3CCD camera to quantify the oxygen concentration in aqueous environment. Compared to Ag-free film, the response time of Ag-containing films were improved from 1.5 s to 1.0 s upon switching from deoxygenated to air saturation and from 65 s to 45 s from air saturation to fully deoxygenated. The response times of the Ag-free film obtained by knifing was 2.0 s upon switching from deoxygenated to air saturation and 104 s from air saturation to fully deoxygenated. Results of the evaluation of accuracy, limit of detection, stability, and photostability are presented. An experiment measuring the spatiotemporal variation of oxygen distribution within the photosynthesis and respiration of Chlorella vulgaris is demonstrated. It is shown that the nanofiber-based optical sensor film could serve as a promising method for rapid oxygen monitoring in aqueous applications.