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The Yangtze River, which is the largest in Euro-Asian, receives tremendous anthropogenic nitrogen input and is typically characterized by severe eutrophication and hypoxia. Two major processes, denitrification and anaerobic ammonium oxidation (anammox), play vital roles for removing nitrogen global in nitrogen cycling. In the current study, sediment samples were collected from both latitudinal and longitudinal transects along the coastal Yangtze River and the East China Sea (ECS). We investigated community composition and distributions of nosZ gene-encoded denitrifiers by high throughput sequencing, and also quantified the relative abundances of both denitrifying and anammox bacteria by q-PCR analysis. Denitrifying communities showed distinct spatial distribution patterns that were impacted by physical (water current and river runoffs) and chemical (nutrient availability and organic content) processes. Both denitrifying and anammox bacteria contributed to the nitrogen removal in Yangtze Estuary and the adjacent ECS, and these two processes shifted from coastal to open ocean with reverse trends: the abundance of nosZ gene decreased from coastal to open ocean while anammox exhibited an increasing trend based on quantifications of hzsB and 16S rRNA genes. Further correspondence correlation analysis revealed that salinity and nutrients were the main factors in structuring composition and distribution of denitrifying and anammox bacteria. This study improved our understanding of dynamic processes in nitrogen removal from estuarine to open ocean. We hypothesize that denitrification is the major nitrogen removal pathway in estuaries, but in open oceans, low nutrient and organic matter concentrations restrict denitrification, thus increasing the importance of anammox as a nitrogen removal process.

Coccolithophores are cosmopolitan, major calcifying protists that have significant roles in marine carbon cycling. Although the influence of temperature and irradiance fluctuation on coccolithophor...

Adjusting planting density is a common agricultural practice used to achieve maximum yields. However, whether the quality of medicinal herbs can be improved by implementing appropriate planting densities is still uncertain. The medicinal crop Panax notoginseng was used to analyze the effects of planting density on growth and ginsenoside accumulation, and the possible mechanisms of these effects were revealed through metabonomics. The results showed that P. notoginseng achieved high ginsenoside accumulation at high planting densities (8 × 8 and 10 × 10 cm), while simultaneously achieved high biomass and ginsenoside accumulation at moderate planting density of 15 × 15 cm. At the moderate planting density, the primary metabolism (starch and sucrose metabolism) and secondary metabolism (the biosynthesis of phytohormone IAA and ginsenoside) of the plants were significantly enhanced. However, the strong intraspecific competition at the high planting densities resulted in stress as well as the accumulation of phytohormones (SA and JA), antioxidants (gentiobiose, oxalic acid, dehydroascorbic acid) and other stress resistance-related metabolites. Interestingly, the dry biomass and ginsenoside content were significantly lower at low densities (20 × 20 and 30 × 30 cm) with low intraspecific competition, which disturbed normal carbohydrate metabolism by upregulating galactose metabolism. In summary, an appropriate planting density was benefit for the growth and accumulation of ginsenosides in P. notoginseng by balancing primary metabolism and secondary metabolism.

Phytoplankton are known as important harbingers of climate change in aquatic ecosystems. Here, the influence of the oceanographic settings on the phytoplankton community structure in the western South China Sea (SCS) was investigated during two seasons, i.e., the winter (December 2006) and summer (August–September, 2007). The phytoplankton community was mainly composed of diatoms (192 taxa), dinoflagellates (109 taxa), and cyanobacteria (4 taxa). The chain-forming diatoms and cyanobacteria Trichodesmium were the dominants throughout the study period. The phytoplankton community structure displayed distinct variation between two seasons, shifting from a diatom-dominated regime in winter to a cyanobacteria-dominated system in summer. The increased abundance of overall phytoplankton and cyanobacteria in the water column during the summer signifies the impact of nutrient advection due to upwelling and enriched eddy activity. That the symbiotic cyanobacteria–diatom (Rhizosolenia–Richelia) association was abundant during the winter signifies the influence of cool temperature. On the contrary, Trichodesmium dominance during the summer implies its tolerance to increased temperature. Overall, the two seasonal variations within the local phytoplankton community in the western SCS could simulate their community shift over the forthcoming climatic conditions.

In the context of global warming and climate anomaly events, as a response, shifts in phytoplankton phenology were observed in the Strait of Malacca (SM) and Sunda Shelf (SS). Such interactions between phytoplankton structure and physico-chemical factors were less known in narrow straits. Therefore, the spatial distribution pattern and diversity of surface phytoplankton assemblage, local hydrology and nutrient regimes were investigated over the Strait of Malacca and Sunda Shelf (South China Sea, SCS) during 2017 and 2018 pre-monsoon season (spring). Diatoms, dinoflagellates and cyanobacteria were representatives of microphytoplankton in the survey area. Total phytoplankton abundance peaked near Singapore Strait (SGS) and diminished towards SS. From the lower ratio of diatoms to dinoflagellates (

Urbanization leads to the continuous expansion of urban built-up areas and the erosion of green space in urban fringe areas, leading to the continuous decline of biodiversity. Urban planners and managers need corresponding decision support tools to coordinate the contradiction between the utilization and protection of green space, ensure the maintenance capacity of biodiversity in green space, and realize the sustainable development of regional economy, society and ecology. Therefore, based on the Hellwig Method, this study designed a decision-making method of green space utilization and protection in urban fringe areas and applied the method to the decision simulation of single or multiple green space utilization and protection modes. In the decision simulation of a green space utilization mode, we evaluated the Hk values of one or several green space sample units, respectively. The smaller the Hk value, the smaller the influence of the green space unit on the biodiversity maintenance function of the whole green space in the region, so the green space unit can be selected first when making green space utilization planning decisions in the urban fringe. In the decision simulation of green space protection mode, the higher the Hk value of single green space sample unit combination or multiple green space sample unit combination, the greater the influence of the green space unit in the combination on the maintenance function of the overall green space biodiversity in the region. Then, when planning the green space protection in the urban fringe, the combination of such green space sample units should be given priority as the key protection and control objects. As a decision support tool for optimal scheme of green space utilization and protection in urban fringe areas, the method is practical, instructive, reasonable, operable, flexible, and universal.

One strain of unicellular flagellated yellow-green algae was successfully isolated from the coastal area near Tianjin in the Bohai Sea in May 2015. The strain ranged from round to elongated in shape. Most of the cells possessed active motility, and some cells formed non-motile aggregation. Based on evidences from morphology, ultrastructure and molecular analysis, we identified the strain as Pavlova pinguis which belonged to Pavlovophyceae, Haptophyta. For Pavlovophyceae, only Pavlova viridis (Diacronema viridis) was reported in China seas prior to this study and it played an important role in aquaculture. This is the first record of Pavlova pinguis in Chinese waters.

Dynamic stochastic resonance (DSR) is a distinctive technique for enhancement of dark and low-contrast image. Noise is necessary for DSR based image enhancement and the level of noise will be enlarged simultaneously with brightness, which reduces the perceptual quality of the enhanced image greatly and also increases the difficulty of subsequent denoising because removing high level of noise often leads to serious loss of image details. In this paper, instead of removing noise after the enhancement process is complete, we propose to suppress noise gradually and simultaneously in the process of enhancement. We rewrite the traditional partial differential equation (PDE) based DSR model in variational framework firstly, and then propose a novel total variation regularized (TV) DSR method for image enhancement. The existence and uniqueness of solution of the TV regularized DSR model is proved theoretically. Moreover, we generalize the TV regularized DSR model in variational framework and in PDE framework, respectively, and therefore we can incorporate more existing denoising methods into our approach. Numerical comparisons demonstrate that the proposed technique gives significant performance in terms of contrast and brightness enhancement as well as noise suppression, and therefore can obtain enhanced image with good perceptual quality.

We studied the biodiversity of autotrophic calcareous coccolithophore assemblages at 30 locations in the Eastern Equatorial Indian Ocean (EEIO) (80°–94°E, 6°N–5°S) and evaluated the importance of regional hydrology. We documented 26 species based on the identification of coccospheres and coccoliths, respectively. The coccolithophore community was dominated by Gephyrocapsa oceanica, Emiliania huxleyi, Florisphaera profunda, Umbilicosphaera sibogae, and Helicosphaera carteri. The abundance of coccoliths and coccospheres ranged from 0.2 × 103 to 160 × 103 coccoliths l−1 and 0.2 × 103 to 68 × 103 cells l−1, averaged 23 × 103 coccoliths l−1 and 9.4 × 103 cells l−1, respectively. Biogenic PIC, POC, and rain ratio mean values were 0.50 μgC l−1, 1.047 μgC l−1, and 0.10 respectively. High abundances of both coccoliths and coccospheres in the surface ocean layer occurred on the north of the equator. Vertically, the great majority of coccoliths and coccospheres were concentrated in water taken from depths of

The influence of oceanographic processes on phytoplankton diversity and community structure was examined during a cruise conducted from July to August 2012 in the northern South China Sea (nSCS). One hundred ninety seven seawater samples were collected and analyzed from 41 stations in the nSCS. A total of 215 species were identified belonging to 67 genera, mostly dominated by diatoms (67.36%) followed by dinoflagellates (28.16%). The mean cell abundance of diatoms and dinoflagellates were 1.954 × 103 cells L−1 and 0.817 × 103 cells L−1, respectively. Diatoms mainly distributed in coastal region whereas dianoflaglletes in the open sea. Margalaf's species richness (dMa) was maximum (3.96) at SQD1 station (Depth 15 m), whereas it was minimum (0.07) at SS1 (Depth 200 m). Further, Box-Whisker plot displayed that dissolved inorganic nutrients incresed with depth. Nevertheless, redundacy analysis reveled that phytoplankton density has a negative relationship with nutrients. Overall the presesant study provides latest in-depth information about how the factors influencing the phytoplankton density and diversity in the (nSCS) during summer based on the cruise data which could serve as a reference for the similar study.

Ether-based functionalized amino acid ionic liquids have the advantages of its unique Contribution to low viscosity and high conductivity, as well as the biodegradability of amino acids. Three kinds of ether-based functionalized amino acid ionic liquids 1-(4-methoxybutyl)-3-methylimidazolium glycine ([COC4mim][Gly]), 1-(4-methoxybutyl)-3-methylimidazolium alanine ([COC4mim][Ala]) and 1-(4-methoxybutyl)-3-methylimidazolium threonine ([COC4mim][Thr]) were synthesized. And physicochemical properties, including density, surface tension and refraction, were measured at different experimental conditions. Based on the polarity scale of ionic liquids proposed by Hildebrand theory, an equation of the polarity coefficient Py was proposed. And we found that it can be applied into the determination of polarity for both ionic liquids and molecular liquids. The surface tension of [COC4mim][Gly], [COC4mim][Ala] and [COC4mim][Thr] was estimated by the definitions of the molar surface Gibbs energy and molar refraction. The predicted values γ(pre) have a very high linear correlation with the corresponding experimental ones.

The ecological province based on phytoplankton species composition is important to understanding the interplay between environmental parameters and phytoplankton species composition. The aim of this study was to establish phytoplankton species composition ecological pattern thus elucidate the relationship between environmental factors and the phytoplankton species composition in the ecological provinces. Phytoplankton samples were collected from 31 stations in Yellow Sea (121.00°–125.00°E, 32.00°–39.22°N) in November 2014. The samples were enumerated and identified with the Utermohl method under an optical inverted microscope-AE2000 with magnifications of 200 × or 400 ×. In the present study, a total of 141 taxa belonging to 60 genera of 4 phyla of phytoplankton were identified, among them 101 species of 45 genera were Bacillariophyta, 36 species of 11 genera were Dinophyta, 3 species of 3 genera were Chrysophyta and 1 species of 1 genera was Chlorophyta. The study area was divided into 4 ecological provinces according to an unsupervised cluster algorithm applied to the phytoplankton biomass. A T-S (Temperature-Salinity) scatter diagram depicted with data of water temperature and salinity defined by environmental provinces matched well with the ecological provinces. The results of Canonical Correspondence Analysis (CCA) indicated that the phytoplankton species composition was mainly correlated with temperature, salinity and silicate concentration in the studied area. A method of establishing ecological provinces is useful to further understanding the environmental effects on the marine phytoplankton species composition and the consequent marine biogeochemistry.

Dust deposition is a crucial link of dust cycle that is less constrained in model studies. This study acquired profiles of flux and size distribution of daily dustfall from 2012 to 2013 in Xi'an on the southern Chinese Loess Plateau. On this basis, we made quantitative estimates of dust contribution from particular sources and processes, which provides important boundary conditions for model studies. Regrouping the data into transport- and source-limited deposition scenarios, we revealed that besides precipitation extreme wind speed and average relative humidity are the primary meteorological constraints in the transport- and source-limited scenarios, respectively. Stronger extreme wind speed promotes higher flux and deposition of dust >16 μm, corroborating previous interpretations of variation of flux and grain size of aeolian deposits. However, higher average relative humidity favors lower flux and deposition of dust

To better understand the physicochemical conditions in affecting regional distribution of phytoplankton community, one research cruise was carried out in the Bohai Sea and Yellow Sea during 3rd and 23th May, 2010. The phytoplankton community, including Bacillariophyta (105 taxa), Pyrrophyta (54 taxa), Chrysophyta (1 taxon) and Chlorophyta (2 taxa), had been identified and clearly described from six ecological provinces. And, the six ecological provinces were partitioned based on the top twenty dominant species related with notable physicochemical parameters. In general, the regional distributions of phytoplankton ecological provinces were predominantly influenced by the physicochemical properties induced by the variable water masses and circulations. The predominant diatoms in most of water samples showed well adaptability in turbulent and eutrophic conditions. However, several species of dinoflagellates e.g., Protoperidinium conicum, Protoperidinium triestinum, Protoperidinium sp. and Gymnodinium lohmanni preferred warmer, saltier and nutrient-poor environment. Moreover, the dinoflagellates with high frequency in the Yellow Sea might be transported from the Yellow Sea Warm Current. The horizontal distribution of phytoplankton was depicted by diatoms and controlled by phosphate concentration, while the vertical distribution was mainly supported by light and nutrients availability in the subsurface and bottom layers, respectively.

Coccolithophores, a calcifying phytoplankton group, are a major component of the oligotrophic ocean. The tropical eastern Indian Ocean (EIO) possesses a complex regional hydrological system that also impacts the global climate. Coccolithophores are a major indicator of these oceanographic and air-sea processes. Understanding coccolithophore population dynamics associated with extreme climate events is significant for predicting future ocean biogeochemical studies, and contributing to the regional and global climatic model. Therefore, we used a consecutive 7 years (2011–2018) dataset of coccolithophore assemblages and their organic carbon biomass from the tropical EIO during the spring premonsoon period to interpret the aforementioned climatic changes. Among the 33 identified species, the ecologically important species Gephyrocapsa oceanica, Emiliania huxleyi, Algirosphaera robusta, Florisphaera profunda, Umbilicosphaera sibogae, and Umbellosphaera irregularis dominated the coccolithophore assemblages. In the EIO, regional environmental factors including high-level eddy kinetic energy, equatorial jets and upwelling lead to the patchy distribution of surface coccolithophores, but no signs of interannual spatial variations were observed. Furthermore, this study revealed that variability in euphotic coccolithophore abundance and diversity indices were correlated with global climate anomalies. The variations in the interannual coccolithophore abundance and estimated coccolithophore organic carbon could be a result of global warming and other climatic variabilities. Particularly, an apparent increase in coccolithophore abundance was observed during El Nino and positive Indian Ocean Dipole (IOD) events due to their favorable thermal regimes. In contrast, the abundance of coccolithophores reduced during La Nina and negative IOD events. Overall, our pilot findings would encourage further studies on coccolithophore responses to regional EIO environments and global climatic anomalies.

The use of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) as an in vitro model of the heart is limited by their structurally and functionally immature phenotypes. During heart development, mechanical stimuli from in vivo microenvironments are known to regulate cardiomyocyte gene expression and maturation. Accordingly, protocols for culturing iPSC-CMs have recently incorporated mechanical or electromechanical stimulation to induce cellular maturation in vitro; however, the response of iPSC-CMs to different mechanical strain magnitudes is unknown, and existing techniques lack the capability to dynamically measure changes to iPSC-CM contractility in situ as maturation progresses. We developed a microdevice platform which applies cyclical strains of varying magnitudes (5%, 10%, 15% and 20%) to a monolayer of iPSC-CMs, coincidentally measuring contractile stress during mechanical stimulation using fluorescent nanobeads embedded in the microdevice's suspended membrane. Cyclic strain was found to induce circumferential cell alignment on the actuated membranes. In situ contractility measurements revealed that cyclic stimulation gradually increased cardiomyocyte contractility during a 10-day culture period. The contractile stress of iPSC-CM monolayers was found to increase with a higher strain magnitude and plateaued at 15% strain. Cardiomyocyte contractility positively correlated with the elongation of sarcomeres and an increased expression of β-myosin heavy chain (MYH7) in a strain magnitude-dependent manner, illustrating how mechanical stress can be optimized for the phenotypic and proteomic maturation of the cells. iPSC-CMs with improved maturity have the potential to create a more accurate heart model in vitro for applications in disease modeling and therapeutic discovery.

Volumes and viscosities of electrolyte solutions are important for the design of process engineering and for the understanding of ion–solvent and ion–ion interactions. In this work, densities and viscosities for solutions of tetraalkylammonium bromides (tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide and tetrahexylammonium bromide) in propylene carbonate (PC) + tetrahydrofuran (THF) mixed solvents were determined at 298.15 K. These data were combined with the literature values of LiClO4 and LiBr in the same solvents to derive ion partial molar volumes and viscosity B-coefficients of tetraalkylammonium bromides. It was shown that these values for the tetraalkylammonium cations remained constant with the addition of THF in PC based solutions, which indicates the lack of solvation of large tetraalkylammonium cations in the organic solvents. However, those values for Li+, Br− and ClO4− decreased with increasing mole fraction of THF in PC. The ion–solvent interaction effect (Δ), the solvation radius (R±) and solvation number (ns) were also obtained to elucidate the ion–solvent interaction.

We studied the biodiversity of autotrophic calcareous coccolithophore assemblages at 30 locations in the eastern equatorial Indian Ocean (EEIO) (80°–94° E, 6° N–5° S) and evaluated the importance of regional hydrology. We found 25 taxa of coccospheres and 17 taxa of coccoliths. The coccolithophore community was dominated by Gephyrocapsa oceanica, Emiliania huxleyi, Florisphaera profunda, Umbilicosphaera sibogae, and Helicosphaera carteri. The abundance of coccoliths and coccospheres ranged from 0.192×103 to 161.709×103 coccoliths l−1 and 0.192×103 to 68.365×103 cells l−1, averaged at 22.658×103 coccoliths l−1 and 9.386×103 cells l−1, respectively. Biogenic PIC, POC, and rain ratio mean values were 0.498 μgC l−1, 1.047 μgC l−1, and 0.990 respectively. High abundances of both coccoliths and coccospheres in the surface ocean layer occurred north of the equator. Vertically, the great majority of coccoliths and coccospheres were concentrated in water less than 75 m deep. The ratios between the number of coccospheres and free coccoliths across four transects indicated a pattern that varied among different oceanographic settings. The H’ and J values of coccospheres were similar compared with those of coccoliths. Abundant coccolithophores along the equator) mainly occurred west of 90° E, which was in accordance with the presence of Wyrtki jets (WJs). F. profunda was not found in surface water, indicating a stratified and stable water system. U. irregularis dominated in the equatorial zone, suggesting oligotrophic water conditions. Coccosphere distribution was explained by environmental variables, indicated by multi-dimensional scaling (MDS) ordination in response variables and principal components analysis (PCA) ordination in explanatory variables. Coccolithophore distribution was related to temperature, salinity, density and chlorophyll a.

Spatial distribution of phaeopigment and size-fractionated chlorophyll a (Chl a) concentrations were examined in relation to hydrographic conditions in the northern South China Sea (NSCS) during a survey from 20 August to 12 September, 2014. The total Chl a concentration varied from 0.006 to 1.488 µg/L with a mean value of 0.259±0.247 (mean±standard deviation) µg/L. Chl a concentration was generally higher in shallow water ( 200 m), with mean values of 0.364±0.311 µg/L and 0.206±0.192 µg/L respectively. Vertically, the maximum total Chl a concentration appeared at depths of 30–50 m and gradually decreased below 100 m. The size-fractionated Chl a concentrations of grid stations and time-series stations (SEATS and J4) were determined, with values of pico- (0.7–2 µm), nano- (2–20 µm) and micro-plankton (20–200 µm) ranging from 0.001–0.287 (0.093±0.071 µg/L), 0.004–1.149 (0.148±0.192 µg/L) and 0.001–0.208 (0.023±0.036 µg/L), respectively. Phaeopigment concentrations were determined at specific depths at ten stations, except for at station A9, and varied from 0.007 to 0.572 (0.127±0.164) µg/L. Nano-and pico-plankton were the major contributors to total phytoplankton biomass, accounting for 50.99%±15.01% and 39.30%±15.41%, respectively, whereas microplankton only accounted for 9.39%±8.66%. The results indicate that the contributions of microplankton to total Chl a biomass were less important than picoplankton or nanoplankton in the surveyed NSCS. Different sized-Chl a had similar spatial patterns, with peak values all observed in subsurface waters (30–50 m). The summer monsoon, Kuroshio waters, Zhujiang (Pearl) River plume, and hydrological conditions are speculated to be the factors controlling the abundance and spatial heterogeneity of Chl a biomass in the NSCS.

Diatoms are a successful group of marine phytoplankton that often thrives under adverse environmental stress conditions. Members of the Skeletonema genus are ecologically important which may subsist during silicate stress and form a dense bloom following higher silicate concentration. However, our understanding of diatoms&rsquo, underlying molecular mechanism involved in these intracellular silicate stress-responses are limited. Here an iTRAQ-based proteomic method was coupled with multiple physiological techniques to explore distinct cellular responses associated with oxidative stress in the diatom Skeletonema dohrnii to the silicate limitation. In total, 1768 proteins were detected, 594 proteins were identified as differentially expressed (greater than a two-fold change, p &lt, 0.05). In Si-limited cells, downregulated proteins were mainly related to photosynthesis metabolism, light-harvesting complex, and oxidative phosphorylation, corresponding to inducing oxidative stress, and ROS accumulation. None of these responses were identified in Si-limited cells, in comparing with other literature, Si-stress cells showed that ATP-limited diatoms are unable to rely on photosynthesis, which will break down and reshuffle carbon metabolism to compensate for photosynthetic carbon fixation losses. Our findings have a good correlation with earlier reports and provides a new molecular level insight into the systematic intracellular responses employed by diatoms in response to silicate stress in the marine environment.