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1.
Planta Med ; 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32512614

RESUMO

Sweet potato is a functional food with potential antitumor properties, but the bioactive constituents and biological mechanisms remain unclear. In this study, we investigated the antitumor effect of daucosterol linolenate extracted from sweet potato and its potential mechanism. An MTT assay indicated that DLA inhibited the proliferation of breast cancer MCF-7 cells but had only weak effects on the proliferation of MDA-MB-231, 4T1, and MCF-10A cells. Flow cytometry analysis revealed that daucosterol linolenate induced apoptosis of MCF-7 cells. Experiments with MCF-7 xenograft in nude mice further confirmed that DLA inhibited tumor growth dose-dependently. After DLA treatment, the expressions of B-cell lymphoma 2 and vascular endothelial growth factor were decreased and that of cleaved caspase 3 was increased as compared to the TC group. DLA also down-regulated the expression of phosphoinositide 3-kinase/protein kinase B and repressed insulin-induced phosphoinositide 3-kinase/protein kinase B activation. Our findings suggest that DLA suppresses breast tumor growth through inactivating the phosphoinositide 3-kinase/protein kinase B pathway.

2.
Mar Pollut Bull ; 152: 110912, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32479286

RESUMO

The oxygen minimum zones (OMZs) and other hypoxic seawaters are considered as the main areas of oceanic nitrogen loss. The laboratory simulation culture was conducted to study the main reactions, rates and proportions of dissolved inorganic nitrogen (DIN) in different dissolved oxygen concentrations seawater, with aim of clarifying the process of nitrogen loss in hypoxic seawater. The results showed that the change of DIN in hypoxic water could be divided into three stages. In the first stage, the main reactions were the dissimilatory nitrate reduction to ammonium (DNRA) and denitrification. In the second stage, anammox and denitrification were main reactions. In the last stage, anammox was the most important nitrogen loss reaction; nitrogen loss eventually reached a relative balance with the input from sediment mineralization. Based on the data obtained from the last stage, the annual nitrogen loss could be estimated to be about 240-260 Tg in the global OMZs.

3.
Phytomedicine ; 76: 153216, 2020 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-32534357

RESUMO

BACKGROUND AND PURPOSE: Gastric cancer is one of the major malignancies worldwide. Epiberberine (EPI) is a major alkaloid from Coptis chinensis Franch and the antitumor property of EPI remains poorly understood. METHOD: The inhibition on gastric cancer cells was observed by MTT assays and colony formation experiments. The apoptosis, cell cycle, and reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) in gastric cancer cells were analyzed by Flow cytometry. The anti-tumor effect of EPI was evaluated with the MKN-45-beraring nude mice, and the potential mechanisms were explored by RNA-seq, qPCR, siRNA silencing and western blotting. RESULTS: EPI inhibited the proliferation of human gastric cancer cell lines MKN-45 (harboring wild-type p53) and HGC-27 (harboring mutant p53) in a dose dependent manner. EPI induced the apoptosis and cell cycle arrest in these two cell lines, of which MKN-45 cells are more sensitive to EPI than HGC-27 cells. Further experiments indicated that EPI induced the accumulation of ROS and decreased of ΔΨm in MKN-45 cells. The significant differentially expressed genes obtained by RNA-seq were distinctly enriched in the p53 signaling pathway. The apoptosis induced by EPI in MKN-45 cells would be effectively inhibited with the treatment of p53 siRNA and p53 inhibitor PFT-α. Western blotting demonstrated that EPI diminished the expression of Bcl-2 and XIAP, and increased those of p53, Bax, p21, p27, Cytochrome C and Cleaved-caspase 3. Animal experiments confirmed that EPI significantly alleviated tumor growth in MKN-45 xenograft mice via p53/Bax pathway. CONCLUSIONS: These data indicated that EPI could be a novel anti-tumor candidate against MKN-45-related gastric cancer via targeting p53-dependent mitochondria-associated pathway.

4.
Ying Yong Sheng Tai Xue Bao ; 31(5): 1753-1762, 2020 May.
Artigo em Chinês | MEDLINE | ID: mdl-32530255

RESUMO

Amino sugars (AS) are one of the important biochemical components in the natural organic matter pool. Clarifying the sources and transformations of AS would facilitate our understan-ding of the microbial regulation of organic matter. As an emerging technology, compound-specific isotope analysis of amino sugars (CSIA-AS) provides more detailed dynamic information of indivi-dual AS in natural environment. Here, we systematically summarized the determination methods of CSIA-AS and gave an overview on innovative applications in the cycling of AS. CSIA-AS can be performed by gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and ion chromatography-isotope ratio mass spectrometry (IC-IRMS). Each method has its own advantages and disadvantages, but reliable results can be achieved after calibration. The mean residence time of AS is relatively low in soil organic matter, and the bacterial-derived muramic acid possesses a higher minera-lization rate than glucosamine, galactosamine, and mannosamine. The source and metabolic transformation of AS are affected by the substrate, which is related to the specific response of microbial community to different carbon and nitrogen sources. The promotion of CSIA-AS technology requires further optimization of method and integration with other approaches such as microbial screening to decipher the source, transformation, fate and regulatory mechanisms of organic matter.


Assuntos
Amino Açúcares , Carbono , Isótopos de Carbono , Isótopos de Nitrogênio , Solo
5.
Biochem Pharmacol ; 175: 113933, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32224138

RESUMO

Studies have shown that palmatine (PAL) has anti-cancer effects. However, the activity and potential mechanisms of PAL against colorectal cancer remain elusive. The results showed that PAL significantly inhibited the proliferation of colon cancer cells in vitro and in vivo without significant effect on non-tumorigenic colon cells. Target prediction and clinical sample database analysis suggested that PAL may contribute to colon cancer cells phase arrest and apoptosis by targeting aurora kinase A (AURKA). Inhibition and overexpression of AURKA proved that PAL induces G2/M phase arrest and apoptosis in colon cancer cells by targeting AURKA. Moreover, PAL promoted intracellular Reactive oxygen species (ROS) production and decreased mitochondrial membrane potential (ΔΨm). PAL reduced the levels of AURKA, Bcl-xl and Bcl2 proteins, and promoted the expression of pro-apoptotic proteins P53, P73, Caspase3 and Caspase9, as well as the increase of cytochrome c (cyt. c) in cell lysates in vitro and in vivo. Together, our study confirmed that PAL induced G2/M phase arrest and mitochondrial-associated pathway apoptosis in colon cancer cells by targeting AURKA. PAL may provide a novel solution for the treatment of colon cancer by serving as a new AURKA inhibitor.

6.
Mar Pollut Bull ; 155: 111147, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32310103

RESUMO

The surface sediments from the Bohai Sea (BS) and the northern Yellow Sea (NYS) were analyzed for acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) to assess the sediment quality. The results indicated that >60% of the samples were found to have possible adverse effects on aquatic life in the BS based on the difference between the concentrations of AVS ([AVS]) and SEM ([SEM]), and the corresponding percentage in the NYS was <25%. Nevertheless, there was no indication of adverse effects for all the BS and the NYS samples when the total organic carbon (TOC) concentration was introduced in the sediment quality evaluation with [AVS] and [SEM]. The grain size composition, TOC, water content and pH all had significant influence on the distribution of [SEM] and the [SEM]/[AVS] ratios; while, in contrast, the distribution of [AVS] could be mainly determined by the redox condition of sediment.

7.
Mar Pollut Bull ; 154: 111071, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32319902

RESUMO

The spatial and temporal characteristics of nutrient concentrations and their influencing factors along longitude 73°E in Prydz Bay were explored. Nutrient concentrations gradually increased from the continental shelf to the open ocean in summer surface water, and the stable environment in the bay, the chlorophyll a and the ice melting were responsible for this distribution characteristic. There was also clear annual variation of nutrients in the surface water. Average concentrations of nutrients showed the highest values in 2010, while they were the lowest in 2009, which may be influenced by El Nino. In the vertical distribution, there were close relationships between chlorophyll a PO4-P, SiO3-Si, S, and NO3-N depths respectively. Moreover, the variation of water masses also influenced the distribution of nutrients. Overall, the spatial and temporal characteristics of nutrients were closely related to environmental change, and especially to the ice melting in the Prydz Bay.

8.
Microbiologyopen ; 9(6): 1207-1224, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32180355

RESUMO

The shallow Caroline Seamount is located in the tropical western Pacific Ocean. Its summit is 57 m below the surface and penetrates the euphotic zone. Therefore, it is ideal for the study of the influence of seamount on plankton distribution. Here, virioplankton abundance and distribution were investigated by flow cytometry (FCM) in the Caroline Seamount in August and September 2017. The total abundance of virus-like particles (VLP) was in the range of 0.64 × 106 -18.77 × 106  particles/ml and the average was 5.37 ± 3.75 × 106  particles/ml. Three to four distinct viral subclusters with similar side scatter but different green fluorescence intensities were identified. Above the deep chlorophyll maximum (DCM), two medium fluorescence virus (MFV) subclusters were discriminated. Between the DCM and the deeper layers, only one MFV subcluster was resolved. In general, low fluorescence viruses (LFV) comprised the most abundant subclusters. In the 75-150 m water column, however, the MFV abundance was higher than the LFV abundance. High fluorescence viruses (HFV) constituted the least abundant subcluster throughout the entire water column. Virioplankton abundance was significantly enhanced at the seamount stations. Environmental factors including water temperature and nitrate concentration were the most correlated with the variation in virioplankton abundance at the seamount stations. Interactions between shallow seamounts and local currents can support large virus standing stocks, causing a so-called indirect "seamount effect" on the virioplankton.

9.
Life Sci ; 245: 117387, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32007575

RESUMO

The aim of this study was to investigate the inhibition of daidzein or/and regular exercise on breast cancer and to reveal the potential biological mechanisms. BALB/c mice pretreated with regular exercise training for 20 days (15 m/min, 60 min/d) were orthotopically transplanted with mouse breast cancer cells (4T1), and then treated with daidzein (145 mg/kg) by gavage for another 22 days. Results showed that exercise or daidzein inhibited tumor growth in mice to a different degree. Particularly, co-treatment with exercise and daidzein showed an obviously synergistic inhibition on the tumor growth (P < 0.01), compared with the tumor control. Further researches indicated that the combination of exercise and daidzein synergistically mobilized and redistributed natural killer cells through upregulating the level of epinephrine and interleukin-6. Moreover, exercise combined with daidzein induces apoptosis in cancer cells via Fas/FasL-initiated mitochondrial apoptosis signaling pathway. These results suggested that regular exercise combined with daidzein may explore a candidate way to prevent and treat the breast cancer.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Apoptose/efeitos dos fármacos , Neoplasias da Mama/terapia , Terapia por Exercício/métodos , Isoflavonas/uso terapêutico , Células Matadoras Naturais/efeitos dos fármacos , Animais , Western Blotting , Linhagem Celular Tumoral , Terapia Combinada , Feminino , Citometria de Fluxo , Camundongos , Camundongos Endogâmicos BALB C , Transplante de Neoplasias
10.
Environ Sci Pollut Res Int ; 27(21): 25933-25942, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31942723

RESUMO

Fuzzy comprehensive assessment was applied, for the first time, to investigate the sediment environmental quality and compare the historical variations of heavy metal pollution in Daya Bay and Jiaozhou Bay, which are representative for sub-tropical and temperate zone of China, respectively. Results shown the Daya Bay had undergone three contrasting stages in the past 100 years. Before 1980s, the sediment was not contaminated by metals and its quality generally conformed to class I of China National Standard for marine sediment quality. During from 1980s to 2000s, however, Daya Bay's environment had experienced significant deterioration. The metal concentrations were significantly higher than the background values, suggesting that there was a sharp increase of metal input. The category of sediment quality fell to class II and class III. Copper was the dominant pollutant during that time. The good thing is sediment quality of Daya Bay has improved to class I since 2000s, and chromium turned to be the major pollutant. As for the Jiaozhou Bay, enrichment of heavy metal was generally not detected and the sediment quality strictly conformed to class I during the recent 90 years. Chromium and zinc were the major pollutants in this bay.

12.
Bioorg Med Chem ; 28(2): 115093, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31859028

RESUMO

AIMS: In Sheng Nong's herbal classic in China, Rhizoma coptidisa(RC) could be used to treat Atopic dermatitsb(AD), but its core ingredient(s) and mechanism remains unknown. The present study aimed to find out the ingredients against AD and expound its mechanisms. MATERIALS AND METHODS: Seven alkaloids were isolated from RC to compare the inhibition against HaCaT cells by MTT assays and apoptosis of cells stimulated with TNF-α/IFN-γ by flow cytometry. The effects of target alkaloids against AD were evaluated on DNCBc (2,4-dinitrochlorobenzene)-induced atopic dermatitis in mice. KEY FINDINGS: Seven alkaloids were isolated from RC successfully. The results from MTT and flow cytometry indicated that among these alkaloids, only magnoflorine d(MAG) had no obvious toxicity on cells, but could inhibit the apoptosis of the cells stimulated with TNF-α/IFN-γ. Further animal experiments confirmed that MAG significantly attenuated the AD-like symptom and inhibited the AD-induced increases in IgE/IL-4, as compared with control (P < 0.01). Moreover, MAG reduced the low Δψme(mitochondrial membrane potential) in HaCaT cells. The results of western blotting proved that MAG inhibited apoptosis of keratinocytes through decreasing the expressions of CTSBf (cathepsin B), Cyte Cg (cytochrome C), Bid and caspase-3/7/8/9. SIGNIFICANCE: Overall, MAG inhibited apoptosis by decreasing the expression of apoptotic pathway-related proteins, and laid a foundation for the study of AD mechanisms.

13.
Sci Rep ; 9(1): 18529, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811228

RESUMO

Coastal wetlands are terrestrial-marine transition zones harboring diverse active microbial communities. The origins of diverse glycerol ether lipids preserved in coastal wetlands are rarely investigated. 16 surface sediments were collected from the coastal wetland at Guangrao (GR), Changyi (CY) and Xiamen (XM), where both climate and sedimentary environment show significant differences. Ten groups of glycerol ether lipids, including isoprenoidal and branched glycerol dialkyl glycerol tetraethers (iGDGTs and bGDGTs), isoprenoidal and branched glycerol dialkanol diethers (iGDDs and bGDDs), hydroxylated isoprenoidal GDGTs and GDDs (OH-GDGTs and OH-GDDs), overly branched GDGTs (OB-GDGTs), sparsely branched GDGTs (SB-GDGTs), hybrid isoprenoid/branched GDGTs (IB-GDGTs) and a tentatively assigned H-shaped branched GDGTs (H-B-GDGTs) were detected and quantified. Sediments collected in the north (Guangrao and Changyi) contain, in general, a lower abundance of GDGT (3.7-55.9 ng/g sed) than samples from south (Xiamen; 251-1020 ng/g sed). iGDGTs and bGDGTs are the predominant components at all sites and account for 17.2-74.3% and 16.1-75.1% of total ether lipids, respectively. The relative abundance of iGDGTs decreases but that of bGDGTs increases with the distance from sea, suggesting a marine vs. terrestrial origin of iGDGT and bGDGTs, respectively. In addition, the methylation index (MIOB/B/SB) of branched GDGTs shows a significant inverse correlation with water content, suggesting that marine waters have a major influence on the microbial communities inhabiting wetland sediment. Such an assumption was confirmed by the distinct lipid pattern of three low water content (<5%) samples collected in an area isolated from tidal flushing. The other isoprenoidal ether lipids, such as iGDDs, OH-GDGTs and OH-GDGTs, have a similar distribution as iGDGTs, indicating a common biological source, so do the corresponding non-isoprenoidal ether lipid series with bGDGTs. The BIT value increases with increasing distance from the sea, which implies that the BIT index can be probably applied to trace past sea level change in costal wetland settings. The reconstructed temperature from TEX86 shows significant offset from observed data, but only little deviation for the MBT/CBT calculated temperature. This suggests that the MBT/CBT has the potential to reconstruct past temperatures in coastal wetland settings.

14.
Mar Pollut Bull ; 143: 163-174, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31789152

RESUMO

Nutrients distribution and influencing factors in three seamount areas named Y3, M2 and C4 of the Tropical Western Pacific Ocean (TWPO) were investigated. Nutrients showed obvious uplifts around the three seamounts, consistent with the uplifts of isotherms and isohalines, indicating the existence of a bottom-up process of nutrients. Meanwhile, compared with the stations away from seamount and the reference stations in the TWPO, nutrients concentrations around seamount were much higher. Among the three seamounts, the average nutrients concentrations were highest in Y3, while they were lowest in C4. Moreover, compared with the obvious nitrogen limitation in Y3 and M2, the N:P (13.5:1) and Si:N (6.1:1) were closed to the Redfield ratio. The current-seamount interaction was the determining influencing factor on nutrients distribution, causing the hydrology dynamic changes such as uplifts and Taylor column. Meanwhile, T and S also affected nutrients distribution, especially nutrients and T showed significant negative correlations.


Assuntos
Nitrogênio/análise , Fósforo/análise , Água do Mar/análise , Silício/análise , Nutrientes , Oceano Pacífico , Clima Tropical
15.
Environ Pollut ; 255(Pt 1): 113247, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541839

RESUMO

The occurrence and distribution of 168 pharmaceutically active compounds (PhACs) in the surface seawater of Jiaozhou Bay (JZB) were investigated using ultra-high-performance liquid chromatography in tandem with a triple-quadrupole mass spectrometer equipped with an electrospray ionization source (UHPLC-ESI-MS-MS). Thirty-six compounds were detected, and 17 of these compounds were first detected in seawater, including sulfabenzamide, sulphacetamide, cephalonium, desacetyl-cefotaxime, cefminox, cefotaxime, cephradine, cefazolin, carprofen, nabumetone, glibenclamide, glimepiride, glipizide, prednisone, fluoromethalone, diazepam and amantadine. The total concentration of PhACs in the surface seawater ranged from 23.6 ng/L to 217 ng/L. The compounds found at the highest mean concentrations included amantadine (24.7 ng/L), lincomycin (8.55 ng/L), carprofen (8.30 ng/L), and tetracycline (7.48 ng/L). The PhAC concentration was higher in the inner bay than in the outside of the bay. In the inner bay, the eastern district showed higher concentrations of PhACs than the western district. Input from the Licun River may be the primary source of pollution. A statistically significant positive correlation was observed between nutrients and PhACs in seawater. Phosphate can be used to indicate the distribution of PhACs in JZB. Based on the individual risk quotient (RQ) values, lincomycin and ofloxacin posed high risks to the relevant aquatic organisms in JZB, especially in the eastern parts. Regular monitoring is required to evaluate the levels of PhACs as they are constantly released into JZB.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/análise , Organismos Aquáticos , Baías/química , China , Ecologia , Medição de Risco , Rios/química , Água do Mar/química , Espectrometria de Massas em Tandem/métodos
16.
Arch Biochem Biophys ; 672: 108064, 2019 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-31390527

RESUMO

S-equol is the exclusive enantiomeric form of the soy isoflavone metabolite produced by human intestinal bacterial flora, which has strong anti-cancer activity. Based on this, the purpose of this study was to investigate the anti-breast cancer mechanism of S-equol. We examined the effects of S-equol on proliferation and apoptosis of MCF-7 cells by cell counting kit-8 assay and flow cytometry. Screening for microRNAs and predicting their target genes using the starBase and Targetscan website, respectively. Protein expression was detected by Western blot. The microRNA level were quantified by real-time PCR. The results showed that S-equol inhibited the proliferation of breast cancer MCF-7 cells in a time- and dose-dependent manner and promoted apoptosis of MCF-7 cells. The expression of miR-10a-5p was significantly decreased in breast cancer tissues and breast cancer cell lines, and the expression of miR-10a-5p was negatively correlated with the proliferation of MCF-7 cells. Luciferase reporter experiments demonstrated that miR-10a-5p directly targets PIK3CA 3'UTR to function. It was further found that S-equol exerts an anti-breast cancer effect by up-regulating miR-10a-5p and inhibiting the PI3K/AKT pathway. Our study revealed the mechanism of S-equol against breast cancer, and miR-10a-5p may be a potential target for the treatment of breast cancer.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Equol/farmacologia , MicroRNAs/metabolismo , Transdução de Sinais/efeitos dos fármacos , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Equol/química , Humanos , Células MCF-7 , Proteínas Proto-Oncogênicas c-akt/metabolismo , Estereoisomerismo
17.
J Pharm Biomed Anal ; 174: 718-727, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295647

RESUMO

The present study provides the method for simultaneous separation and determination of concentration and evaluates anti-breast cancer activity of three phytosterols from the sweet potato (Ipomoea batatas L.): daucosterol linolenate (DLA), daucosterol linoleate (DL), and daucosterol palmitate (DP). A cell viability assay revealed that the three phytosterols had a stronger inhibitory effect on MCF-7 than MDA-MB-231 breast cancer cell line, and had no effects on non-tumorigenic MCF-10A cells. In vivo experiments demonstrated that DLA, DL, and DP suppressed tumor growth in MCF-7 xenograft breast cancer model in nude mice. Given the anti-breast cancer activity of DLA, DL, and DP, an HPLC method for the determination of their content in the sweet potato was developed. The method had satisfactory linearity (R2 = 0.9992-0.9999). The limits of detection (LOD) were in the range of 2.5-10 µg/mL, the limits of quantification (LOQ) were 5-25 µg/mL, and the recovery rates were 97.64-103.02%. Additionally, the HPLC method was successfully validated in eight sweet potato cultivars. This novel technique can be applied for the determination of DLA, DL, and DP in the sweet potato.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/terapia , Ipomoea batatas/química , Fitosteróis/farmacologia , Extratos Vegetais/farmacologia , Animais , Antineoplásicos/isolamento & purificação , Linhagem Celular Tumoral , Sobrevivência Celular , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Limite de Detecção , Células MCF-7 , Camundongos , Camundongos Nus , Fitosteróis/isolamento & purificação , Análise de Regressão , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Ecotoxicol Environ Saf ; 182: 109371, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31252350

RESUMO

Dissolved Organic Carbon (DOC) is a key organic compound in wet precipitation, but few data are available in China marginal seas. To probe the concentration, deposition flux, seasonality, source and potential ecological environmental effects of precipitation DOC, in this study, one-year precipitation samples were collected at Jiaozhou Bay (JZB), a typical anthropogenic-influenced semi-enclosed bay in the western Yellow Sea for the first time from June 2015 to May 2016. The concentrations of DOC in precipitation were highly variable with a volume-weighted mean (VWM) concentration of 3.63 mg C L-1, which was mostly higher than those in other areas. DOC concentrations were lower in wet season than that in dry season due to the dilution from more amount of rainfall. The wet deposition flux of DOC was calculated to be 3.15 g C m-2 yr-1 with 68.7% of which occurred in wet season mainly owing to the promoting of more rainfall amount. Besides, local emissions together with the long-range transport of pollutants were other factors controlling precipitation DOC. Fossil fuel combustion particularly coal burning was considered to be the leading source of precipitation DOC based on correlation analysis with some generally accepted indicators. Wet deposition dominates the external input of DOC at JZB by comparison with riverine input with a percentage of 54%. Heavy storm may exert enrichment effect on DOC levels in the surface water of JZB, and then promote the secondary productivity. This study emphasizes that wet deposition is an important process that should be seriously considered in the models of global/regional carbon biogeochemical cycling.


Assuntos
Poluentes Atmosféricos/análise , Baías/química , Monitoramento Ambiental/métodos , Compostos Orgânicos/análise , Chuva/química , Água do Mar/química , China , Ecologia , Combustíveis Fósseis/análise , Oceanos e Mares , Estações do Ano , Solubilidade
19.
Chemosphere ; 232: 315-326, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154193

RESUMO

To constrain the resuspension influence to the biogeochemical behavior of trace metals (TMs) in settling materials, the concentrations and chemical speciations of macro-elements (Al, Fe, Mn) and selected particulate TMs (V, Cr, Co, Cu, Zn, Ga, Sr, Cd, Ba, Tl, Pb, U) in trap-collected particles (TCPs), surface sediments (SS) and core sediment samples (CS5) of the Jiaozhou Bay were compared. Two approaches, mass conservation method and vertical two end-members mixing model, both calculated a resuspension ratio of more than 90%. Greater TM concentrations and Al-normalization levels than SS/CS5 determined the TCPs an important TM-sink, predominantly owing to grain-size effects and TCP-specific characteristics, i.e., structural capacity of organic-Fe associations for TMs' scavenging, preferential remineralization of TM than biogenic elements in autochthonous microorganisms. Comparison revealed distinct, Fe mineral controls on TM sequestration patterns: higher metal sequestration associated with amorphous Fe oxyhydroxides, while less reactive crystalline Fe oxides hold less metal. Nevertheless, turbulent hydrodynamics muted the wide TM retention divergences between TCP and SS, which should have happened based on different Fe minerals distribution for TCP/SS. The net effect of TM release by the organic carrier phase and then adsorption principally onto Mn/Fe oxyhydroxide phase for raised overall TCP-TM concentrations was also identified.


Assuntos
Monitoramento Ambiental , Metais/análise , Poluentes Químicos da Água/análise , Adsorção , Baías , China , Meio Ambiente , Sedimentos Geológicos/química , Metais Pesados/análise , Oligoelementos/análise
20.
Mar Pollut Bull ; 144: 79-91, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31180009

RESUMO

To exploit the resolving ability of rare earth element and yttrium (REY) in resuspension binary mixing model, and discover potential new REY-related resuspension proxy, this preliminary research studied the geochemical signature of REY in different Jiaozhou Bay samples including surficial/core sediments and settling trap-collected particles. Close quantitative relation for bulk concentration in particles, sediments and fine-grained fraction of major river sediments around the Yellow Sea, approved the priority contribution of catchment detrital materials. Moreover, common characteristics occurred for compartment-specific partitioning REY signatures in six operated-defined fractions, and multiple REY normalization pattern indexes (i.e. Y/Ho divergence, and Ce/Eu anomalies). All constrain the application of REY in resuspension discrimination of marginal shallow seas. However, linearity with different slopes and intercepts were plotted for the MREE bulge index versus HREE/LREE figure in reducible amorphous Fe-oxides fraction, which could provide new discrimination perceptions.


Assuntos
Baías/química , Monitoramento Ambiental/métodos , Metais Terras Raras/análise , Poluentes Químicos da Água/análise , Ítrio/análise , China , Sedimentos Geológicos , Oceanos e Mares , Rios/química
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