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See also the Commentary on this article by Zhang et al., 242: 327–330. [ABSTRACT FROM AUTHOR]

This study investigated the nutrients and heavy metal contents in water body and sediment of the Napahai Wetland during summer through fluorescence spectroscopy and inductively coupled plasma optical emission spectrometer analysis. Results indicated that most of the heavy metal contents in water body are derived from municipal sewage when the stream passes through the town center. The primary organic compounds in the water body of the Nachi River and the Napahai Wetland were hydrophobic acid, fulvic acid, and aromatic protein-like compounds. Cr, Ni, Cd, As, Pb, and V contents in wetland sediments significantly differ from sampling sites and depths, and varied in the following order: V > Cr > Ni > Pb > As > Cd. Principal component analysis showed that the distribution of heavy metals was primarily affected by urbanization and secondarily affected by other abiotic factors. [ABSTRACT FROM PUBLISHER]

A novel halophilic bacterium capable of heterotrophic nitrification–aerobic denitrification was isolated from marine sediments and identified as Vibrio diabolicus SF16. It had ability to remove 91.82% of NH 4 + -N (119.77 mg/L) and 99.71% of NO 3 − -N (136.43 mg/L). The nitrogen balance showed that 35.83% of initial NH 4 + -N (119.77 mg/L) was changed to intracellular nitrogen, and 53.98% of the initial NH 4 + -N was converted to gaseous denitrification products. The existence of napA gene further proved the aerobic denitrification ability of strain SF16. The optimum culture conditions were salinity 1–5%, sodium acetate as carbon source, C/N 10, and pH 7.5–9.5. When an aerated biological filter system inoculated with strain SF16 was employed to treat saline wastewater, the average removal efficiency of NH 4 + -N and TN reached 97.14% and 73.92%, respectively, indicating great potential of strain SF16 for future full-scale applications. [ABSTRACT FROM AUTHOR]

Abstract Bivalves are extensively employed as biomonitors of coastal pollution, but the comparability among different species and geographic environments needs to be further scrutinized. The present study conducted a meta-analysis of trace metals (Ag, Cd, Cr, Cu, Ni, Pb, Ti, and Zn) in the soft tissues of three groups of marine bivalves (oysters, mussels, and clams) collected from China and worldwide. By conducting cumulative frequency distribution analysis of metal distribution, we modeled the 5% cumulative values as the bio-baseline metal concentrations in these bivalves. We further modeled their potential baseline concentrations using a well-developed biokinetic model. The baseline concentrations of Cd, Cu, and Zn in the tissue-specific Environmental Quality Standards (EQSs) for China were 0.99, 34.5, and 340 μg/g dw in oysters, 0.38, 4.32, and 49.6 μg/g dw in mussels, and 0.35, 3.02, 51.4 μg/g dw in clams, respectively. Of the 8 metals examined in this study, the calculated baseline concentrations of Ag, Cr, Cd, Cu and Zn in the oysters were 3.7–48, 2.7–3.6, 2.6–2.8, 8.0–11.4, 6.6–6.8 times higher than those in the mussels and clams, and only Ti showed comparable baseline concentrations among the three bivalves (8.43–9.67 μg/g dw). These data strongly suggested the inter-group as well as inter-metal difference in the baseline metal concentrations in marine bivalves. Further, the potential baseline concentrations of Cd and Cu predicted by the biokinetic model were comparable to those modeled by the probability frequency distribution. Combined statistical frequency analysis and biokinetic modeling therefore provided an innovative method to establish the baseline metal concentrations in bivalves and the tissue-specific EQSs, which are now urgently needed for coastal management, biomonitoring, and geochemical records in the world. Graphical abstract Unlabelled Image Highlights • Meta-analysis of trace metals in the soft tissues of three marine bivalves was conducted. • Bio-baseline metal concentrations in the bivalves were modeled using probability frequency distribution. • Baseline metal concentrations in marine bivalves varied among groups and metals. • Biokinetic and probability frequency distribution models predicted comparable baseline concentrations. [ABSTRACT FROM AUTHOR]

Abstract: To study the relationships between species distribution and environmental variables, calanoid copepods were classified and enumerated, and environmental variables were analyzed along 91 sites of the Pearl River Estuary (China) and adjacent waters. The 91 sites were divided into 3 groups based on surface salinity: the Inner area had salinity level below 10‰ and was mostly located in the Pearl River Estuary, the Coastal area had salinity between 10‰ and 32‰ and was almost located along the coastline, while the Offshore area had salinity level higher than 32‰ and was mainly located in the open area. Indicator Species Analysis was conducted to identify the indicator species within each group from among all calanoid copepods taxa. We found that the Inner area was characterized by Acartiella sinensis, Pseudodiaptomus poplesia and Pseudodiaptomus inopinus, the coastal area was characterized by Temora turbinata and Subeucalanus subcrassus, and the Offshore area was characterized by Paracandacia truncata, Subeucalanus subtenuis, Euchaeta rimana, Pareucalanus attenuatus, Rhincalanus cornutus, Cosmocalanus darwini, Centropages gracilis, Undinula vulgaris, Nannocalanus minor and Paraeuchaeta russelli. Canonical Correspondence Analysis (CCA) was used to identify relevant biotic and abiotic parameters that can best explain the distribution of calanoid copepods. CCA showed that during the summer of 2006, salinity, nutrient variables, especially SiO3–Si, NO3–N and DTN, Depth and Chl a were the environmental variables that strongly impacted the distribution and community structure of calanoid copepods. [Copyright &y& Elsevier]

Eco-toxicity investigation of polymer materials was considered extremely necessary for their potential menace, which was widely use as mulching materials in agricultural. In this study, polyethylene (PE), polystyrene (PS) and synthetic biomaterials-Ecoflex and cellulose were applying into soil cultivated with two potential indicator plants species: oat (A v ena sati v a) and red radish (Raphanus sativum). Variety of chemical, biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm. The F-value of biomass, pH, heavy metal and electoral conductivity of Raphanus behaved significant different from T0. Significant analysis results indicated biodegradation was fast in PE than PS, besides, heavy metals were dramatically decrease in the end implied the plant absorption may help decrease heavy metal toxicity. The increase value at T2 of Dehydrogenase activity (0.84 higher than average value for Avena & 0.91 higher for Raphanus), Metabolic Index (3.12 higher than average value for Avena & 3.81 higher for Raphanus) means during soil enzyme activity was promoted by biodegradation for its heterotrophic organisms' energy transportation was stimulated. Statistics analysis was carried on Biplot PC1 (24.2% of the total variance), PC2 (23.2% of the total variance), versus PC3 (22.8% of the total variance), which indicated phosphatase activity and metabolic index was significant correlated, and high correlation of ammonium and protease activity. Furthermore, the effects were more evident in Raphanus treatments than in Avena , suggesting the higher sensitivity of Raphanus to polymers treatment, which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds. [Display omitted] Variety of chemical, biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm. Biodegradation was fast in PE than PS, besides, heavy metals were dramatically decrease in soil at the end of experiment implied the plant absorption of metal may help decrease heavy metal toxicity of soil. During experiments, soil enzyme activity was promoted by polymer biodegradation for its heterotrophic organisms' energy transportation was stimulated. The effects were more evident in Raphanus treatments than in Avena , suggesting the higher sensitivity of Raphanus to the polymers treatment, which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds [ABSTRACT FROM AUTHOR]

Cadmium (Cd) and arsenic (As) are two of the most toxic elements. However, the chemical behaviors of these two elements are different, making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(II) and As(V) removal. To solve this problem, we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB), a novel ternary material, to perform this task, wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties. The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(II) and 35.59 mg/g for As(V), which is much higher compared to pristine biochar (11.06 mg/g, 0 mg/g for Cd(II) and As(V), respectively). The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(II) to HFMB, while ligand exchange was the adsorption mechanism that bound As(V). Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Phosphorus loss during food production and consumption and the effect of urbanization on cropland loss have been widely studied. However, the effect of urbanization on phosphorus metabolism in agricultural areas has received little attention. Using substance flow analysis, this paper reveals the effect of urbanization on food phosphorus metabolism. By developing comprehensive mass balance models, we quantify P flows in a typical agricultural area after summarizing the critical pathways for the effect of urbanization on P metabolism. Then, based on indicators such as per capita food P demand or loss, we discuss the effect of urbanization on food consumption, food production, food export and food waste management. Urbanization resulted in the growth of urban population, the increase of animal-derived food proportion in diet, the increase of food export and its animal-derived food proportion, more emission and declined recycling rate of urban excreta and food waste. Quantitative analysis of urbanization and P metabolism reveals that the increase of P loss driven by urbanization was mainly due to the expansion of animal-derived food production and the increase of food export. The sum of their contribution reached 99.2% of the cumulative urbanization-related P loss over the 20 years. These factors led to more P demand and losses in the regional food consumption-production system. Opportunities for sustainable phosphorus use in food production and consumption system rely on the improvement of P use efficiency in agricultural production, especially animal-derived foods. In this case, the increase of P loss from animal production accounted for 84.5% of total increase of cumulative urbanization-related P loss during the period, due to much lower P use efficiency in livestock feeding and aquaculture than grain planting. Moreover, it was more useful to recycle food waste P and excreta P (as crop fertilizer) than to enhance P removal in wastewater treatment plants. Graphical abstract Image 1 Highlights • P flows for the food system in Zhangzhou steadily grew from 1995 to 2014. • Urbanization affected diet pattern, population structure, trade and waste and excreta reuse. • Urbanization significantly increased local average per capita food P consumption. • Increasing food P consumption caused greater P input and loss within the production-consumption system. • A closed P loop mainly relied on reusing lost P in agriculture rather than removing P in WWTPs. [ABSTRACT FROM AUTHOR]

Cell cycle re-entry, in which Fra-1 (transcription factor FOS-related antigen 1) plays an important role, is a key process in neuronal apoptosis. However, the expression and function of Fra-1 in retinal ganglion cell (RGC) apoptosis are unknown. To investigate whether Fra-1 was involved in RGC apoptosis, we performed a light-induced retinal damage model in adult rats. Western blot revealed that up-regulation of Fra-1 expression appeared in retina after light exposure (LE). Immunostaining indicated that increased Fra-1 was mainly expressed in RGCs in retinal ganglion cell layer (GCL) after LE. Co-localization of Fra-1 with active caspase-3 or TUNEL-positive cells in GCL after LE was also detected. In addition, Fra-1 expression increased in parallel with cyclin D1 and phosphorylated mitogen-activated protein kinase p38 (p-p38) expression in retina after LE. Furthermore, Fra-1, cyclin D1, and active caspase-3 protein expression decreased by intravitreal injection of SB203580, a highly selective inhibitor of p38 MAP kinase (p38 MAPK). All these results suggested that Fra-1 may be associated with RGC apoptosis after LE regulated by p38 MAPK through cell cycle re-entry mechanism. [ABSTRACT FROM AUTHOR]

The bacterial communities played important roles in the high productivity mangrove ecosystem. In this study, we investigated the vertical distributions of rhizosphere bacteria from three mangrove species (Bruguiera gymnorrhiza, Kandelia candel and Aegiceras corniculatum) in Beilun Estuary, China using high throughput DNA pyrosequencing of the 16S rRNA gene. Phylogenetic analysis showed that bacterial communities from mangrove rhizosphere sediments were dominated by Proteobacteria (mostly Deltaproteobacteria and Gammaproteobacteria), followed by Chloroflexi, Bacteroidetes, Planctomycetes and Acidobacteria. However, the ANOVA analysis on Shannon and Chao1 indices indicated that bacterial communities among sediments of the three mangrove species varied more strongly than the sampling depths. In addition, the PCA result demonstrated that the bacterial communities could be separated into three groups according to the mangrove species. Moreover, the dominated orders Rhodospirillales, GCA004 and envOPS12 were significantly different among sediments of the three mangrove species. The results of this study provided valuable information about the distribution feature of rhizosphere bacteria from Chinese mangrove plants and shed insights into biogeochemical transformations driven by bacteria in rhizosphere sediments. [ABSTRACT FROM AUTHOR]

Pyruvate kinase isozyme type M2 (PKM2), a key glycolytic enzyme, which is involved in ATP generation and pyruvate production, participates in tumor metabolism, growth, and other multiple cellular processes. However, one attractive biological function of PKM2 is that it translocates to the nucleus and induces cell apoptosis. Recently, increased PKM2 has been found in age-related macular degeneration (AMD), but little is known regarding its function in the AMD pathophysiology. To investigate whether PKM2 participated in retinal degeneration, we performed a light-induced retinal damage model in adult rats. Western blot and immunohistochemistry analysis showed a significant up-regulation of PKM2 in retinal ganglion cells (RGCs) layer (GCL) after light exposure. Immunofluorescent labeling indicated that PKM2 located mainly in RGCs. Co-localization of PKM2 and active caspase-3 as well as TUNEL in RGCs suggested that PKM2 might participate in RGC apoptosis. In addition, the expression patterns of cyclin D1 and phosphorylated extracellular signal-regulated kinase (p-ERK) were parallel with that of PKM2. Furthermore, PKM2, cyclin D1, and active caspase-3 protein expression decreased by intravitreal injection of U0126, a highly selective inhibitor of MAPK/ERK kinase. Collectively, we hypothesized that PKM2 might participate in RGC apoptosis after light-induced retinal damage medicated by p-ERK through cycle re-entry mechanism. [ABSTRACT FROM AUTHOR]

A sediment core was collected and dated using 210 Pb ex dating method off the waterspout of nuclear power base of Daya Bay, northeastern South China Sea. The γ-emitting radionuclides were analyzed using HPGe γ spectrometry, gross alpha and beta radioactivity as well as other geochemical indicators were deliberated to assess the impact of nuclear power plants (NPP) operation and to study the past environment changes. It suggested that NPP provided no new radioactivity source to sediment based on the low specific activity of 137 Cs. Two broad peaks of TOC, TC and LOI accorded well with the commercial operations of Daya Bay NPP (1994.2 and 1994.5) and LNPP Phase I (2002.5 and 2003.3), implying that the mass input of cooling water from NPP may result into a substantial change in the ecological environment and Daya Bay has been severely impacted by human activities. [ABSTRACT FROM AUTHOR]

Marine ecosystem is a complex nonlinear system. However, ecosystem health assessment conventionally builds on a linear superposition of changes in ecosystem components and probably fails to evaluate nonlinear interactions among various components. To better reflect the intrinsic interactions and their impacts on ecosystem health, an ecosystem coordination index, defined as the matching level of ecosystem structure/services, is proposed and incorporated into the ecosystem health index for a systematic diagnosis in the Pearl River Estuary, China. The analysis results show that the ecosystem health index over the last three decades decreased from 0.91 to 0.50, indicating deteriorating from healthy to unhealthy status. The health index is 3–16% lower than that calculated using the common method without considering ecosystem coordination. Ecosystem health degradation in the Pearl River Estuary manifested as significant decreases in structure/services and somewhat mismatching among them. Overall, the introduction of coordination in ecosystem health assessment could improve the understanding of the mechanism of marine ecosystem change and facilitate effective restoration of ecosystem health. [ABSTRACT FROM AUTHOR]

The increasing input of fungicides has emerged as a global concern for agroecosystem stability and sustainability. Agroecosystem resilience has been linked to microbiome response, however, is not well understood. Focusing on a widespread triazole-class fungicide triadimefon in the paddy ecosystem, we characterized that the soils and sediments were dominant triadimefon reservoirs with the peak level at 195 μg kg−1 and 31.3 μg kg−1, respectively, but essential for the resilience of paddy ecosystem to triadimefon. In paddy simulation models, the half-life of triadimefon in soil-sediment was 8.4–28.9 days, while it was prolonged to 86.6–115.5 days after elimination of resident microbial community. Phospholipid fatty acid profiling and high-throughput sequencing showed that the distinctive bacterial community responses contributed to variable degradation of triadimefon in paddy soils and sediments. Sphingomonas and Xanthomonas were identified as positive responders of the keystone taxa in the responsive bacteriome, whereas Enterobacter were negative responders that declined over time. Synthetic assemblages combined with quantitative polymerase chain reaction further validated that Sphingomonas and Xanthomonas were involved in sustaining soil-sediment resilience to triadimefon contamination. Collectively, our results revealed that the shaping of soil and sediment bacteriomes was responsible for the resilience of the paddy agroecosystem to fungicide contamination. [Display omitted] • The resilience of the paddy ecosystem to triadimefon was dominantly conferred by the soils and sediments. • The resilience in paddy soils and sediments was associated with bacterial community. • Distinctive bacteriome responses to triadimefon were observed between paddy soils and sediments. • The keystone taxa of triadimefon-responsive bacteriome were characterized in paddy soils and sediments. [ABSTRACT FROM AUTHOR]

• FNA + PF pretreatment increased TSS removal of WAS than either FNA or PF pretreatment. • FNA + PF pretreated WAS showed extremely high BMP during subsequent anaerobic digestion. • FNA + PF pretreatment promoted the enrichment of Methanolinea, Mesotoga , and Methanobacterium. • FNA + PF pretreatment stimulated flexible pathways of methanogenesis during anaerobic digestion. The increasing production of waste activated sludge (WAS) from wastewater treatment plants presents an inherent environmental burden. In this study, Free nitrous acid combined with potassium ferrate (FNA + PF) pretreatment was used to enhance solubilization and biochemical methane potential of WAS. Results indicated that the maximum removal rates of total suspended solid by PF, FNA, and PF + FNA pretreatment were 21.84%, 38.09%, and 56.17%, respectively. The biochemical methane potential of WAS without pretreatment reached 61.22 L CH 4 /kg VSS added while this value increased to 147.07 L CH 4 /kg VSS added after FNA + PF pretreatment (0.06 g/g TSS NaNO 2 and 0.25 g/g TSS K 2 FeO 4). Shotgun metagenomic analysis revealed that FNA + PF pretreatment could increase the diversity and stability of microbial communities by shifting methanogenic pathways from strictly acetoclastic to acetoclastic/hydrogenotrophic, thereby enhancing methane production. This study suggested that FNA + PF pretreatment is a promising technology to reduce WAS and enhance methane production by pretreated WAS during anaerobic digestion. [ABSTRACT FROM AUTHOR]