State Key Laboratory of Estuarine and Coastal Research

(Nano)microplastics induce neurotoxicity and oxidative damage.

Marine snow is a predominant form of sinking particulate carbon in the marine water column and represents a mechanism for transporting microplastics to the sea floor.

Abstract Plastics have become an integral component in agricultural production as mulch films, nets, storage bins and in many other applications, but their widespread use has led to the accumulation of large quantities in soils. Rational use and reduction, collection, reuse, and innovative recycling are key measures to curb plastic pollution from agriculture. Plastics that cannot be collected after use must be biodegradable in an environmentally benign manner. Harmful plastic additives must be replaced with safer alternatives to reduce toxicity burdens and included in the ongoing negotiations surrounding the United Nations Plastics Treaty. Although full substitution of plastics is currently not possible without increasing the overall environmental footprint and jeopardizing food security, alternatives with smaller environmental impacts should be used and endorsed within a clear socio-economic framework. Better monitoring and reporting, technical innovation, education and training, and social and economic incentives are imperative to promote more sustainable use of plastics in agriculture.

Mounting evidence from proxy records suggests that variations in solar activity have played a significant role in triggering past climate changes. However, the mechanisms for sun-climate links remain a topic of debate. Here we present a high-resolution summer sea-surface temperature (SST) record covering the past 9300 yr from a site located at the present-day boundary between polar and Atlantic surface-water masses. The record is age constrained via the identification of 15 independently dated tephra markers from terrestrial archives, circumventing marine reservoir age variability problems. Our results indicate a close link between solar activity and SSTs in the northern North Atlantic during the past 4000 yr; they suggest that the climate system in this area is more susceptible to the influence of solar variations during cool periods with less vigorous ocean circulation. Furthermore, the high-resolution SST record indicates that climate in the North Atlantic regions follows solar activity variations on multidecadal to centennial time scales.

Dysprosium (Dy)-doped BiFeO3 (BFO) (BFDO) nanoparticles were prepared by an ethylene glycol based sol-gel method. Partial substitution of Dy (0%–20%) at the Bi site results in a change from the rhombohedral structure (x=0) to the orthorhombic structure (x=0.10,0.20) of BFO nanoparticles. The average grain size varies from 65 to 24 nm when Dy concentration increases from x=0 to x=0.20. Saturated magnetization Ms of BDFO increases with increasing Dy concentration and decreasing grain size. Moreover, dielectric properties were measured up to high frequency ∼95 MHz, and Dy dopant was found to be helpful to improve dielectric ordering and reduce loss. Surprisingly, the large magnetodielectric coefficient was found to be 4.7% in the as-prepared BFO nanoparticles, and −6.3% in Bi0.8Dy0.2FeO3 at H=100 Oe and f=75 MHz.

The aza-MBH reaction of imines 1 and beta-naphthyl acrylate 2 in the presence of C-6' modified beta-isocupreidine derivative 1c (0.1 equiv) and beta-naphthol 5 (0.1 equiv) afforded the corresponding (3S)-aza-MBH adducts 4 in high yield and excellent enantiomeric excess. These catalytic conditions allowed the aliphatic imines to be employed for the first time as electrophilic partners of the aza-MBH reaction. The coexistence of two H-bond donors with different acidic strengths was found to be crucial for the observed high enantioselectivity.

Abstract The characteristics of swell propagation play an important role in the forecasting of ocean waves as well as on research on global climate change, wave energy development, and disaster prevention and reduction. To reveal the propagation routes, terminal targets and speeds of swells that originate from the southern Indian Ocean westerly (SIOW), an intraseasonal swell index (SI) was defined based on the 45 year (September 1957 to August 2002) ERA‐40 wave reanalysis data product from the European Center for Medium‐Range Weather Forecasts (ECMWF). The results show that the main body of the SIOW‐related swells typically spread to the waters off Sri Lanka and Christmas Island, while the branches spread to the Arabian Sea and other waters. The propagation speeds of swells originated in the SIOW were fastest in May and August, followed by November, and were slowest in February. Swells usually required 4–6 days to propagate from the western part of the SIOW to the waters off Sri Lanka and Christmas Island, whereas swells usually required 2–4 days to propagate from the eastern part of the SIOW to the waters off Christmas Island.

Abstract The anthropogenic‐induced global warming and local urbanization exert important influences on temperature extremes in Eastern China. Here we use China station observations and climate models to investigate their effects on the warm and cold days and nights simultaneously. We quantified the contribution from these two factors based on an optimal fingerprinting method. We find that both anthropogenic and urbanization signals can be clearly detected and separated from each other in the nighttime temperature extremes. The effect of urbanization may explain as much as one third of the observed changes in cold and warm nights while the urbanization signal is weak in the daytime extremes. The results are robust against sampling uncertainty in the estimate of urbanization signal, but uncertainty due to collinearity between the urbanization signal and global warming is difficult to assess.

The abundances of ARGs increased after exposure to ZnO NPs, especially at low doses (0.2 and 1 mg L⁻¹). Compared to MGEs and dissolved Zn, the microbial community contributed more to the variations in ARGs in estuarine waters when exposed to ZnO NPs.

Abstract In many large estuaries there are significant variations in flow conditions due to the interaction between tide (with spring–neap changes) and river discharge (with wet–dry seasons), which is key to understanding the evolution of the morphology and the resultant equilibrium state. To explore whether there exists an equilibrium state, and what might control such a state in such a dynamic environment, both numerical and analytical methods have been used to investigate the relative importance of tide and river contributions to the work done locally and globally over a wide range of discharge conditions in the Yangtze estuary. In particular, we have quantified the contributions from the tidal flow, the river flow and the tide–river interaction in terms of energy and its dissipation under different river discharge conditions. Model results suggest that there is a state of minimum tidal work for the case representing the wet season, when river and tide are doing uniform work locally and minimum work globally, within the bi‐directional tidal reach for tide and along the whole estuary for river. We also observe that the system is not optimized for other conditions (peak discharge and low flows during the dry season), but the system would tend to do the minimum work possible given the constraints on the system (e.g. imposed forcing conditions and available sediment supply). Results, therefore, are consistent with the use of these two energetic optimization principles, and the proposed method could be applicable to other alluvial estuaries. Copyright © 2015 John Wiley & Sons, Ltd.

Runoff samples were collected from four functional areas (traffic, residential, commercial and industrial) and four roof types (old concrete, new concrete, old clay and new clay) in central Shanghai, China, during rain events. The event mean concentrations (EMCs) of three forms of nitrogen (NH4+N,NO3-N,NO2-N) and the temporal variations of total phosphorus (TP) were then measured to evaluate the effects of runoff from different areas on water quality management. The results revealed that the TP levels varied significantly in the samples collected from different functional areas and roof types during rain events. In addition, although the NO3-N and NO2-N concentrations in runoff remained well below the fifth class values of the national surface water quality standards, the NH4+N levels were 1.36, 1.17, 1.10 and 0.85 times higher than the standard value in samples collected from commercial, traffic, industrial, and residential areas, respectively. Similarly, the concentrations of NH4+N in samples collected from old concrete, new concrete, old clay and new clay roofs exceeded the fifth class standard by 6.66, 5.72, 4.32 and 3.32 times, respectively. And the NO3-N levels were 1.86 and 1.53 times higher than the standard values in runoff samples collected from new and old concrete roofs, respectively.

The first inter-calibration study of the stable silicon isotope composition of dissolved silicic acid in seawater,<italic>δ</italic>³⁰Si(OH)₄, is presented as a contribution to the international GEOTRACES program.

Offshore wind energy has the potential to ease energy and environmental crises, improve people’s living standards on remote islands, and, finally, make contributions to sustainable development. Accurate energy evaluations should be performed before the exploitation of offshore wind energy; this includes not only assessments of the resource’s historical characteristics but also a focused effort on understanding future issues. Using simulated wind data from the Coupled Model Intercomparison Project, phase 5 (CMIP5), this paper compares and analyses wind energy characteristics globally for the 2080–2099 period (future) relative to the 1980–1999 period (past). The classification of both past and future wind energy is also presented. The results show a positive trend for future global offshore wind energy. Compared with the past, the extent of areas with wind power density (WPD) greater than 400 W m−2 will expand. In the future, across most of the global oceans, the effective wind speed occurrence and the occurrence of a WPD higher than 200 W m−2 will be greater than that in the past, generally by 10%. The extents of the sub-rich, available, and poor regions will decrease, while the regions with a wind energy class of 7 will expand. The future wind energies of the North and South Poles show a “seesaw” phenomenon.

Abstract Soil organic matter (SOM) in northern high‐latitude regions is a major component of the global carbon cycle. However, the yield of soil‐dissolved organic matter (DOM) during soil‐water interactions and its chemical characteristics and reactivities remain poorly understood. We report here elemental composition and isotopic signatures of bulk‐SOM from northern Alaska, and yields of water‐leachable soil‐DOM, including dissolved organic carbon, dissolved organic nitrogen, and dissolved organic phosphorus, and nutrients (dissolved inorganic nitrogen and phosphate). The bulk‐SOM contained 5,400–373,900 μg‐C/g‐soil, 500–12,610 μg‐N/g‐soil, and 38.6–384 μg‐P/g‐soil, with a C/N ratio of 13–37 and a C/P ratio of 80–3,911. The water‐extractable dissolved organic carbon, dissolved organic nitrogen, and dissolved organic phosphorus only accounted for 0.58–2.5%, 0.91–3.4%, and 1.2–3.0% of their corresponding total soil‐OC, N, and OP, respectively. While SOM‐δ 13 C was less variable (−27.08‰ to −26.49‰) showing the same overall C source, 14 C‐ages varied widely from 1,170 ± 20 to 16,200 ± 55 years before present, indicating different deposition‐conditions and subsequent‐processes among the soil samples. The specific‐UV‐absorbance at 254 nm (or aromaticity) of soil‐DOM differed considerably and was negatively correlated to spectral slope values. A humic‐like (C1), a low‐molecular‐weight fulvic‐like (C2), and a protein‐like component (C3) were identified as the major fluorescent‐DOM components. The C3/C2 and C3/C1 ratios generally increased with SOM‐ 14 C‐age, suggesting a preferential degradation/transformation of humic‐like and fulvic‐like components or a transformation/production of protein‐like components within permafrost. Both biological and humification indices increased with 14 C‐age, excluding the oldest soil, which pointed to a preferential preservation or transformation/production of protein‐like DOM within permafrost, implying that soil‐DOM derived from old permafrost can be highly vulnerable and readily decomposed upon permafrost thaw.

ABSTRACT Between the years 1933–2001, 460 red tide events were found in China's coastal water. The scope of red tide occurrence has extended over all the coastal provinces of China, and the three major areas with high red tide frequency are the Bohai sea, the sea area near the Shengsi Archipelago and Huaniaoshan Island on the outer side of the Changjiang River estuary and the Hangzhou Bay, and the coastal waters on the east side of the Zhujiang River estuary from Hong Kong to East Guangdong. In the past 20 years, the frequency of red tides has been tending upwards. The years of 1988–1990 and 1998–2001 saw the most serious red tides along China's coastal waters, with the latter period as the peak. The average area of a single red tide, i.e., the scale of red tides, is expanding every year, and in 2001 rose to about 500 km2. Every year, China's red tides occur from south to north, with those in the South China Sea occurring from March to May, those in the East China Sea from April to August and those in the Bohai and Huanghai Seas from May to September.

Abstract This paper examines the possible influence of external forcings on observed changes in precipitation extremes in the mid-to-high latitudes of Asia during 1958–2012 and attempts to identify particular extreme precipitation indices on which there are better chances to detect the influence of external forcings. We compare a recently compiled dataset of observed extreme indices with those from phase 5 of the Coupled Model Intercomparison Project (CMIP5) simulations using an optimal fingerprinting method. We consider six indices that characterize different aspects of extreme precipitation, including annual maximum amount of precipitation falling in 1 day (Rx1day) or 5 days (Rx5day), the total amount of precipitation from the top 5% or top 1% daily amount on wet days, and the fraction of the annual total precipitation from these events. For single-signal analysis, the fingerprints of external forcings including anthropogenic agents are robustly detected in most studied extreme indices over all Asia and for midlatitude Asia but not for high-latitude Asia. For two-signal analysis, anthropogenic influence is detectable in these indices over Asia at 5% or slightly less than 5% significance level, whereas natural influence is not detectable. In high-latitude Asia, anthropogenic influence is detected only in a fractional index, representing a stark contrast to the midlatitude and full Asia results. We find relatively smaller internal variability and thus higher signal-to-noise ratio in the fractional indices when compared with the other ones. Our results point to the need for studying precipitation extreme indices that are less affected by internal variability while still representing the relevant nature of precipitation extremes to improve the possibility of detecting a forced signal if one is present in the data.

The Qarun Lake in the Faiyum Oasis (Egypt) provides a unique record of Holocene environmental and climate change in an arid area largely devoid of fossil proxy records. Multiple lithological, palaeontological and geochemical proxies and 32 radiocarbon dates from the 26‐m‐long core FA ‐1 provide a time series of the lake's transformation. Our results confirm that a permanent lake appeared in the Holocene at c. 10 cal. ka BP . The finely laminated lake sediments consist of diatomite, in which diatoms and ostracods together with lower concentrations of ions indicate a freshwater environment at the end of the early and middle Holocene. This freshwater supply was closely associated with regular inflows of the Nile water during flood seasons, when the Intertropical Convergence Zone ( ITCZ ) migrated northwards in Africa, although it has probably never reached the Faiyum Oasis. Local rainfall, possibly connected with a northern atmospheric circulation, may have been important during winter. Several phases in the lake's evolution are recognized, represented by oscillations between deep open freshwater conditions during more humid climate and shallow fresh to brackish water during drier episodes. After a long freshwater phase, the lake setting has become more brackish since c. 6.2 cal. ka BP as indicated by diatoms and increasing contents of evaporite ions in the sediment. This clearly shows that since that time the lake has occasionally become partly desiccated. This is a result of reduced discharge of the Nile. In the late Holocene the lake was mostly brackish and then gradually turned into a saline lake. This natural process was interrupted about 2.3 cal. ka BP when a man‐made canal facilitated water inflow from the Nile. The examined FA ‐1 core can be used as a reference age model of climate change in the Holocene and its impact on the development and decline of ancient civilizations in northeastern Africa.

The large prehistoric city of Liangzhu and its associated earthen dike emerged on the Yangtze delta-coast after two millennia of occupation in this area by scattered communities. Details of its development have been widely discussed in the literature. Our results reveal that the city was selectively built at the head of an embayment backed by hills, with close access to food, freshwater and timber, and with protection from coastal hazards. Radiocarbon and optically stimulated luminescence (OSL) dating shows that it was built around 4.8–4.5 ka, and the earthen dike was constructed a little later at ~ 4.1 ka. During this time, saltwater wetlands were changing to freshwater in response to rapid coastal progradation as the postglacial sea-level rise stabilized. This facilitated rice farming and furthered the development of the city with elaborate city planning. The younger large-scale earthen dike and artificial ponds possibly suggest increasing demand for flood mitigation and irrigation.

The overwhelming magnitude of coal-fired power plants has caused an inevitable release of metal-containing nanoparticles (MNPs) into the atmosphere, which may be inhaled into the respiratory system and cause oxidative stress. In this study, MNPs and oxidative potential (OP) were analyzed in <1 μm fractions of 56 coal fly ashes collected from Chinese CFPPs. The particle number concentrations (PNCs) of Fe- and Ti-containing NPs, as the dominant MNPs in CFAs, were in the range of 1.5 × 109 to 9.4 × 1010 and 6.4 × 108 to 4.1 × 1010 particles/mg, with average particle sizes of 87 and 89 nm, respectively. Average OP values of <1 μm fractions were 1.4–2.2 nmol AA min–1 μg–1 for three simulated lung fluids, which were 2–3 orders of magnitude higher than those of urban atmospheric PM2.5. According to structural equation model analysis, metal concentrations in <1 μm fractions, PNCs of Fe-/Ti-containing NPs, and their corresponding dissolved Fe/Ti (including NPs with minute sizes) can regulate OP of <1 μm fractions in CFAs. Elevated PNCs of MNPs in CFAs can be produced by CFPPs burning low-rank coals and with a low combustion efficiency boiler (e.g., circulating fluidized-bed boiler). Once entering lung fluids, they likely release more dissolved metals or tiny corresponding NPs, thus generating greater OP. This study provides the first comprehensive investigation of OP generated by MNPs in CFAs.

As an organochlorine insecticide, endosulfan has been widely banned or restricted, but it is still largely used in many developing countries. Previous studies have shown multiple adverse health effects of endosulfan. However, the neurotoxicity of endosulfan has not been fully elucidated. In this study, endosulfan isomers (α-/β-endosulfan) and their major metabolites (endosulfan sulfate, endosulfan diol, and endosulfan lactone) were, respectively, exposed to human neuroblastoma SH-SY5Y cells. Results showed that both α-endosulfan and β-endosulfan caused decrease of cell viability and morphological damages in a dose-dependent manner. Their median effective concentrations (EC50s) were respectively 79.6 μM (α-endosulfan) and 50.37 μM (β-endosulfan) for 72 h exposure. EC50s of α/β-endosulfan mixture were lower than that of the single isomer. However, EC50s of its metabolites were higher than that of technical endosulfan. Endosulfan and its metabolites caused increases of reactive oxygen species and the lipid peroxidation, but decrease of superoxide dismutase in a dose-dependent manner. These results indicate that α-endosulfan exhibits higher neurotoxicity than β-endosulfan. Mixture of endosulfan isomers shows stronger cytotoxicity than the single isomer. After endosulfan is degraded, cytotoxicity of its metabolites decreases gradually. The neurotoxicity of endosulfan and its metabolites is closely related to oxidative damage and antioxidative deficit.