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1.
Sci Total Environ ; 734: 139237, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32450399

RESUMO

The effects of microbial colonization and biofilm formation on microplastics in the marine and coastal environments have aroused global concern recently. However, the simultaneous influences of exposure time and depth on biofilm formation, and subsequently on the properties variations of microplastics is less studied. In this study, polyethylene (PE) film was exposed at three depths (2 m, 6 m, and 12 m) for three time periods (30 days, 75 days, and 135 days) in the coastal seawater of Yellow Sea, China. The results show that the total amount of biofilms markedly increased with exposure time, but decreased with water depth. Typical morphologies and compositions of biofilms such as coccus-, rod-, disc-shaped bacteria and filaments, as well as a dense layer of extracellular polymeric substances were observed on the surfaces of the PE microplastics. Biofilm formation could decrease the hydrophobicity of PE microplastics, and increase the abundances of hydrophilic C-O and CO groups on the surface of PE. Alphaproteobacteria, Gammaproteobacteria and Bacteroidia were identified as the core microbiome of the PE associated biofilms, while the dominant bacteria families vary from the early to the late phases of the biofilm formation. Our results indicate that microplastics associated biofilms could affect the environmental processes and fates of microplastics in the marine and coastal environment.


Assuntos
Biofilmes , China , Monitoramento Ambiental , Microplásticos , Água do Mar , Poluentes Químicos da Água
2.
Science ; 368(6492)2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32409447

RESUMO

Nitrogen fixation, the reduction of atmospheric dinitrogen gas (N2) to ammonia, is critical for biological productivity but is difficult to study in the vast expanse of the global ocean. Decades of field studies and the infusion of molecular biological, genomic, isotopic, and geochemical modeling approaches have led to new paradigms and questions. The discovery of previously unknown N2-fixing (diazotrophic) microorganisms and unusual physiological adaptations, combined with diagnostic distributions of nutrients and their isotopes as well as measured and modeled biogeographic patterns, have revolutionized our understanding of marine N2 fixation and its role in the global nitrogen cycle. Anthropogenic upper-ocean warming, increased dissolved carbon dioxide, and acidification will affect the distribution and relative importance of specific subgroups of N2 fixers in the sea; these changes have implications for foodwebs and biogeochemical cycles.


Assuntos
Cianobactérias/classificação , Cianobactérias/metabolismo , Diatomáceas/microbiologia , Fixação de Nitrogênio , Oceanos e Mares , Água do Mar/microbiologia , Amônia/síntese química , Dióxido de Carbono/análise , Oxirredução , Fotossíntese , Filogenia , Água do Mar/química , Simbiose
3.
Sci Total Environ ; 732: 139293, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32438147

RESUMO

Biodegradation is a major determinant of chemical persistence in the environment and an important consideration for PBT and environmental risk assessments. It is influenced by several environmental factors including temperature and microbial community structure. According to REACH guidance, a temperature correction based on the Arrhenius equation is recommended for chemical persistence data not performed at the recommended EU mean surface water temperature. Such corrections, however, can lead to overly conservative P/vP assessments. In this paper, the relevance of this temperature correction is assessed for petroleum hydrocarbons, using measured surface water (marine and freshwater) degradation half-time (DT50) and degradation half-life (HL) data compiled from relevant literature. Stringent screening criteria were used to specifically select data from biodegradation tests containing indigenous microbes and conducted at temperatures close to their ambient sampling temperature. As a result, ten independent studies were identified, with 993 data points covering 326 hydrocarbon constituents. These data were derived from tests conducted with natural seawater, or freshwater, at temperatures ranging from 5 to 21 °C. Regressions were performed on the full hydrocarbon dataset and on several individual hydrocarbons. The results were compared to the trend as predicted by the Arrhenius equation and using the activation energy (Ea) as recommend in the REACH Guidance. The comparison shows that the correction recommended in REACH Guidance over predicts the effect of temperature on hydrocarbon biodegradation. These results contrast with temperature manipulated inocula where the test temperature is different from the ambient sampling temperature. In these manipulated systems, the effect of temperature follows the Arrhenius equation more closely. In addition, a more striking effect of temperature on the lag phase was observed with longer lag phases more apparent at lower temperatures. This indicates that the effect of temperature may indeed be even lower when considering hydrocarbon biodegradation without the initial lag phase.


Assuntos
Biodegradação Ambiental , Água Doce , Hidrocarbonetos , Petróleo , Água do Mar
4.
Environ Monit Assess ; 192(6): 356, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32394090

RESUMO

The composition and metabolic properties of cultivable heterotrophic aerobic bacteria, the levels of indicator bacteria, and physicochemical parameters were investigated in the seawater samples collected from 20 stations in coastal areas of the eastern part of the Black Sea, Turkey, between May 2017 and February 2018. The levels of indicator bacteria were detected above the national limit values during the study period. Thirty-five different bacterium species were identified. Enterobacteriaceae was recorded as the most dominant family (34.2%), and Gammaproteobacteria was recorded as the most dominant class (74.2%). Bacteriological threats on human and ecosystem health were determined in coastal areas of the Southeastern Black Sea. The determination of the high levels of indicator bacteria, the high ratio of fecal coliform/fecal streptococci (FC/FS ratio), and pathogenic bacteria regarding human and ecosystem health showed that these coastal areas under the influences of terrestrial and human-sourced bacteriological pollution. This study has contributed to the increase of knowledge of understanding the protection and rehabilitation ways of the Black Sea coastal regions against land-based pollution sources considering the interdependent structure of all Black Sea countries. Coastal areas are accepted as the most fragile part of the marine environments and our findings showed the potential bacteriological risks in coastal areas of the Southeastern Black Sea as an important example. Serious precautions should be taken for the protection in this area and such coastal ecosystems to prevent hazardous problems.


Assuntos
Ecossistema , Monitoramento Ambiental , Água do Mar/microbiologia , Bactérias , Mar Negro , Humanos , Turquia , Microbiologia da Água
5.
Rev Bras Parasitol Vet ; 29(2): e018219, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428182

RESUMO

Sea lice are widespread copepods in marine teleost around the world. In this paper the first record of Caligus asperimanus Pearse, 1951 in the Western South Atlantic is documented parasitizing Lutjanus jocu and Lutjanus vivanus caught from coastal zones of Espírito Santo and Rio de Janeiro State, respectively.


Assuntos
Copépodes/anatomia & histologia , Perciformes/parasitologia , Animais , Oceano Atlântico , Brasil , Copépodes/classificação , Feminino , Água do Mar
6.
Sci Total Environ ; 730: 139096, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32388110

RESUMO

Various environmental challenges are rapidly threatening ecosystems and societies globally. Major interventions and a strategic approach are required to minimize harm and to avoid reaching catastrophic tipping points. Setting evidence-based priorities aids maximizing the impact of the limited resources available for environmental interventions. Focusing on protecting both food security and biodiversity, international experts prioritized major environmental challenges for intervention based on three comprehensive criteria - importance, neglect, and tractability. The top priorities differ between food security and biodiversity. For food security, the top priorities are pollinator loss, soil compaction, and nutrient depletion, and for biodiversity conservation, ocean acidification and land and sea use (especially habitat degradation) are the main concerns. While climate change might be the most pressing environmental challenge and mitigation is clearly off-track, other issues rank higher because of climate change's high attention in research. Research and policy agendas do not yet consistently cover these priorities. Thus, a shift in attention towards the high-priority environmental challenges, identified here, is needed to increase the effectiveness of global environmental protection.


Assuntos
Abastecimento de Alimentos , Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais , Concentração de Íons de Hidrogênio , Água do Mar
7.
Int J Syst Evol Microbiol ; 70(5): 3323-3327, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32375986

RESUMO

The Gram-strain-negative, rod-shaped, facultatively anaerobic, non-motile bacterial strain, designated S1-10T, was isolated from marine sediment. Strain S1-10T grew at 4-42 °C (optimally at 30-35 °C), at pH 7.0-10 (optimally at pH 9) and in the presence of 0.5-8 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S1-10T was related to the genus Aequorivita and had highest 16S rRNA gene sequence similarity to Aequorivita viscosa 8-1bT (97.7%). The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The main respiratory quinone was menaquinone 6 (MK-6). The genomic DNA G+C content of strain S1-10T was 34.6 mol%. The polar lipid profile of strain S1-10T contained phosphatidylethanolamine, two aminolipids, two glycolipids, one phosphoglycolipid and three unidentified polar lipids. In addition, the maximum values of in silico DNA-DNA hybridization (isDDH) and average nucleotide identity (ANI) between strain S1-10T and A. viscosa CGMCC 1.11023T were 15.4 and 75.7 %, respectively. Combined data from phenotypic, phylogenetic, isDDH and ANI analyses demonstrated that strain S1-10T is the representative of a novel species of the genus Aequorivita, for which we propose the name Aequorivita sinensis sp. nov. (type strain S1-10T=CGMCC 1.12579T=JCM 19789T). We also propose that Vitellibacter todarodis and Vitellibacter aquimaris should be transferred into genus Aequorivita and be named Aequorivita todarodis comb. nov. and Aequorivita aquimaris comb. nov., respectively. The type strain of Aequorivita todarodis comb. nov. is MYP2-2T (= KCTC 62141T= NBRC 113025T) and the type strain of Aequorivita aquimaris comb. nov. is D-24T (=KCTC 42708T=DSM 101732T).


Assuntos
Flavobacteriaceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Glicolipídeos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
8.
J Environ Manage ; 267: 110648, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421678

RESUMO

The Amery ice shelf (AIS) dynamics and mass balance play key role to decipher changes in the global climate scenario. The spatio-temporal changes in morphology of the AIS were studied into a number of transects at 5 km uniform intervals using multi-dated Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite data (2001-2016) of the austral summer months (January-March). Past ice shelf extents have been reconstructed and future ice shelf extents were estimated for 5- and 10-year time periods. The rate changes of AIS extent were estimated using the linear regression analysis and cross-validated with the coefficient of determination (R2) and root-mean-square error (RMSE) methods. Further, the changes in shelf extent were linked to prevailing factors viz. mass changes, Southern Annular Mode (SAM) index, and ocean-air temperatures. The study reveals that the AIS extent has been prograded at the rate of 994 m/year with an average 14.5 km increase in the areal extents during 2001-2016, as compared to the year 2001, whereas, the maximum advancement in ice shelf extent was recorded during the 2006-2016 period. Based on the linear regression analysis, the predicted ice shelf extents (i.e., the summer 2021 and 2016) show progradation in all the transects. About 52% of transects exhibit ±200 m RMSE values, indicating better agreement between the estimated and satellite-based ice-shelf position. The recent changes (2017-2019) observed in the ice shelf are cross validated with predicted ice self-extent rates. The eastern part of Mackenzie Bay to Ingrid Christensen coast recorded advancement in the ice shelf extents and mass which is the feedback of positive SAM along with a decrease in the temperatures (air temperature and sea surface temperature). The present study demonstrates that the combined use of satellite imagery and statistical techniques can be useful in quantifying and predicting ice shelf morphological variability.


Assuntos
Camada de Gelo , Água do Mar , Regiões Antárticas , Clima , Tecnologia de Sensoriamento Remoto
9.
Water Res ; 178: 115866, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32380295

RESUMO

Although submarine groundwater discharge (SGD) comprises an insignificant proportion of the global hydrologic cycle, it contributes significantly to chemical fluxes into the coastal waters due to concentrated constituents in coastal groundwater. Large nutrient loadings derived from SGD can lead to a series of environmental and ecological problems such as algal blooms, resulting in water discoloration, severe dissolved oxygen depletion, and eventually beach closures and massive fish kills. Previous studies have demonstrated the relationship between algal blooms and SGD obtained from direct measurement with seepage meters or from geo-tracer (i.e., radon and radium) based models; these traditional methods are time-consuming, laborious and point monitoring, and can hardly achieve a high spatiotemporal resolution SGD estimation, which is vital in revealing the effects of SGD to algal blooms over a long period. Alternatively, remote sensing methods for high spatiotemporal resolution SGD localization and quantification are applicable and effective. The temperature difference or anomaly between groundwater and coastal water extracted from satellite thermal images can be used as the indicator to localize and detect SGD especially its fresh component (or fresh SGD). In this study, multi-year (2005, 2011 and 2018) radon samples in Tolo Harbour were used to train regression models between in-situ radon (Rn) activity and the temperature anomaly by Landsat satellite thermal images. The models were used to estimate two-decade variations of fresh SGD in Tolo Harbour. The synergistic analysis between the time series of fresh SGD derived from regression models and high spatiotemporal resolution ecological metrics (chlorophyll-a, algal cell counts, and E.coli) leads to the findings that the increase of the fresh SGD associated with high nutrient concentrations is witnessed 10-20 days before the observations of algal bloom events. This study makes the first attempt to demonstrate the strong relation between the SGD and algal blooms over a vicennial span, and also provides a cost effective and robust technique to estimate SGD on a bay scale.


Assuntos
Água Subterrânea , Radônio , Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Água do Mar
10.
Mar Pollut Bull ; 153: 110955, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275519

RESUMO

The ecological risk and potential injury from polycyclic aromatic hydrocarbons (PAHs) from spilled crude oil in water is dependent on whether they are dissolved or associated with droplets/particles. Using oil collected from the Deepwater Horizon incident, laboratory experiments were conducted to develop a computational method to determine the physical state of PAHs in sampled seawater and compare these to results from methods designed to physically separate dissolved and droplet oil used during the spill. The analytical results were used to develop a method to calculate droplet/particulate concentrations from unfractionated water samples based on oil composition and allocation of minimally soluble oil components to the droplet fraction. The computational method is less labor-intensive and costly than field fractionation and can be used to optimize the use of previously collected data. The results also showed that physical separation can result in insoluble high-molecular-weight PAHs being present in the filtrate (i.e., the "dissolved" fraction), potentially leading to an overestimate of dissolved components.


Assuntos
Monitoramento Ambiental/métodos , Poluição por Petróleo , Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Golfo do México , Água do Mar
11.
Chemosphere ; 253: 126656, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32278911

RESUMO

In recent years, ballast water disinfection has been paid much more attention due to the untreated discharged ballast water posing threaten of biological invasion and health related consequences. In this study, an effective and simple approach for ballast water disinfection by just adding potassium peroxymonosulfate (PMS) was assessed, and the role of halide ions in seawater on the enhancement of inactivation was revealed. The reactive species responsible for inactivation, the leakage of intracellular materials, and changes of cellular morphology after inactivation were evaluated to explore the inactivation mechanism. The results showed that Escherichia coli and Bacillus subtilis in ballast water could be totally inactivated within 10 min by adding 0.2 mM PMS alone. The inactivation of bacteria in ballast water fitted to the delayed Chick-Watson model. Chloride and bromide ion in seawater were found to play a crucial role in inactivating bacteria, while the effect of iodide ion could be negligible due to its relative lower concentration in seawater. Chlorine and bromine, produced by the reaction of PMS with chloride and bromide ion, were proved to be the main reactive components that were responsible for the inactivation of bacteria. The extracellular ATP and total nitrogen concentration increased after inactivation which indicated that cell membrane was destroyed by reactive oxidants produced by the reaction between PMS and halide ions. The change of cell morphology confirmed that bacteria were seriously damaged after inactivation. The results suggest that PMS is an attractive alternative disinfectant for ballast water disinfection and this application deserved further research.


Assuntos
Desinfetantes/toxicidade , Desinfecção/métodos , Peróxidos/toxicidade , Navios , Purificação da Água/métodos , Bactérias/efeitos dos fármacos , Bromo , Cloro , Oxidantes , Água do Mar/microbiologia
12.
Chemosphere ; 253: 126706, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32289606

RESUMO

The sorption behavior of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on aged polystyrene (PS) microplastics via seawater soaking, ultraviolet (UV) irradiation, seawater soaking and UV irradiation together was investigated. The effects of environmental factors including salinity, pH, and dissolved organic matter (DOM) on sorption of BDE-47 by the aged PS microplastics were analyzed. The equilibrium sorption capacity of BDE-47 by virgin PS, aged PS with seawater soaking, aged PS with UV irradiation and aged PS with seawater soaking and UV irradiation was 6.16, 4.96, 3.53, and 3.75 ng/g, respectively. The decrease in sorption capacity was related to the increase of surface crystallinity and the appearance of surface oxygen-containing functional groups. The kinetic and isotherm models suggested that aging did not change the sorption mechanism of BDE-47 on PS microplastics. pH had negligible impacts on BDE-47 sorption by virgin and aged PS. Sorption capacity of BDE-47 on aged PS in water with high salinity was lower than that on virgin PS, and DOM has less effect on the sorption of BDE-47 on aged PS.


Assuntos
Éteres Difenil Halogenados/química , Microplásticos/química , Poliestirenos/química , Adsorção , Éter , Cinética , Plásticos , Polímeros , Salinidade , Água do Mar , Poluentes Químicos da Água/análise
13.
Bull Environ Contam Toxicol ; 104(5): 551-558, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32285138

RESUMO

Arsenic (As) bioaccumulation and biotransformation in marine ecosystems involve a number of fields and disciplines such as Environmental Sciences & Ecology, Marine & Freshwater Biology, and Toxicology. Arsenic research in these areas has been developing rapidly in recent years. It is crucial to keep up with the emerging trends and critical development of the collective knowledge. Therefore, a progressively synthesized network was achieved from 6396 original publications that cited 500 articles obtained from an initial topic search between 2010 and 2019. CiteSpace was used to analyze the progress and emerging trends. Results showed that these publications were divided into 13 different but closely related clusters. A major ongoing trend was identified in Cluster #3 and #5, concerning As and other heavy metals as heterogeneous complexants and assessing their overall impacts on human health. Other new emerging trends include evaluating the As profile in estuarial ecosystems and assessing its bioaccumulation and biotransformation along the food chain. Overall, the scientometric analytics of targeting literature performed in this review has offered a valuable and timely approach to evaluate the new emerging trends, providing researchers with up-to-date and critical information in research areas relevant to the searching topic.


Assuntos
Organismos Aquáticos/metabolismo , Arsênico/metabolismo , Bioacumulação , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Organismos Aquáticos/efeitos dos fármacos , Arsênico/análise , Biotransformação , Ecossistema , Cadeia Alimentar , Água Doce/química , Humanos , Metais Pesados/análise , Água do Mar/química , Poluentes Químicos da Água/análise
14.
Mar Pollut Bull ; 153: 110992, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275541

RESUMO

Despite being located at the same latitudes, the Bay of Bengal oxygen deficient zone (ODZ) is markedly different than the Arabian Sea ODZ. The uptake of oxygen in the Bay of Bengal does not lead to denitrification as in the Arabian Sea. This difference in ODZ of the Bay of Bengal and the Arabian Sea is expected to support different benthic fauna. We report that the living benthic foraminifera in the Bay of Bengal ODZ are markedly different than that in the Arabian Sea ODZ. Only four species (Brizalina spathulata, Eubuliminella exilis, Uvigerina peregrina and Rotaliatinopsis semiinvoluta) dominant in the Bay of Bengal ODZ have also been reported from the Arabian Sea oxygen deficient waters. The difference in living benthic foraminifera dominant in the ODZ of the Bay of Bengal and the Arabian Sea, is attributed to the lack of denitrification and associated processes in the Bay of Bengal.


Assuntos
Desnitrificação , Foraminíferos , Baías , Oxigênio , Água do Mar
15.
Mar Pollut Bull ; 153: 111001, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275550

RESUMO

The Arctic is an ecologically diverse area that is increasingly vulnerable to damages from oil spills associated with commercial vessels traversing newly open shipping lanes. The significance of such accidents on Arctic marine habitats and the potential for recovery can be examined using ecological risk assessment (ERA) coupled with a dynamic object-oriented Bayesian network (DOOBN). A DOOBN approach is useful to represent the probabilistic relationships inherent in the interactions between key events associated with an oil spill, including oil dispersion from the source, ice-oil slick interactions, seawater-oil slick formation, sedimentation, and exposures to different aquatic life. From such analysis, a probabilistic cost analysis can be performed to examine the theoretical cost of habitat services lost and restored. The application of an ERA-DOOBN model to assess oil spills in the Arctic is demonstrated using a case study. The utility of the model output for determining habitat restoration costs and developing policy guidelines for ecological response measures in the Arctic is also discussed.


Assuntos
Poluição por Petróleo/estatística & dados numéricos , Regiões Árticas , Teorema de Bayes , Hidrocarbonetos , Medição de Risco/métodos , Água do Mar
16.
Mar Pollut Bull ; 153: 111006, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32275552

RESUMO

The rapid pace of increasing oceanic acidity poses a major threat to the fitness of the marine ecosystem, as well as the buffering capacity of the oceans. Disruption in chemical equilibrium in the ocean leads to decreased carbonate ion precipitation, resulting in calcium carbonate saturation. If these trends continue, calcifying invertebrates will experience difficultly maintaining their calcium carbonate exoskeleton and shells. Because malfunction of exoskeleton formation by calcifiers in response to ocean acidification (OA) will have non-canonical biological cascading results in the marine ecosystem, many studies have investigated the direct and indirect consequences of OA on ecosystem- and physiology-related traits of marine invertebrates. Considering that evolutionary adaptation to OA depends on the duration of OA effects, long-term exposure to OA stress over multi-generations may result in adaptive mechanisms that increase the potential fitness of marine invertebrates in response to OA. Transgenerational studies have the potential to elucidate the roles of acclimation, carryover effects, and evolutionary adaptation within and over generations in response to OA. In particular, understanding mechanisms of transgenerational responses (e.g., antioxidant responses, metabolic changes, epigenetic reprogramming) to changes in OA will enhance our understanding of marine invertebrate in response to rapid climate change.


Assuntos
Ecossistema , Invertebrados/fisiologia , Água do Mar , Aclimatação/fisiologia , Animais , Dióxido de Carbono , Concentração de Íons de Hidrogênio , Oceanos e Mares
17.
Toxicon ; 180: 18-27, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32278765

RESUMO

The presence of potent hepatotoxic cyanotoxins such as nodularin (NOD) in drinking water, groundwater, surface water, seawater and recreational waters presents a major risks to human and environmental health. Human exposure to cyanotoxins could lead to various health effects such as liver damage, jaundice, neurotoxicity and gastroenteritis. Therefore, it is critical to investigate their occurrence in environmental matrices. This study reports the use of tyre-based activated carbon (WTAC) as an adsorbent for preconcentration and removal of nodularin from environmental matrices prior to high performance liquid chromatographic analysis. The preconcentration and adsorption experiments were carried out in presence of other environmental components to consider the external effect on WTAC adsorption of nodularin. Under optimum conditions, the linear dynamic range was 0.05-70 µg L- 1 with a correlation coefficient of 0.9991. The LOD and LOQ (n = 10) in the absence and in the presence of humic acids were 0.012-0.025 µg L- 1 and 0.040-0.083, n = 10), respectively. The repeatability (n = 10) and reproducibility (n = 5) of the method expressed as relative standard deviation (%RSD) were 3.7 and 5.1%, respectively. The maximum adsorption capacity of WTAC was 345 µg g -1. Furthermore, the results demonstrated that the presence of humic acid has an effect on the nodularin adsorption to WTAC. However, high concentrations other coexisting ions such a Cl-, NO3-, PO43-, HCO3-, SO42- had no significant the effect on the adsorption process. The proposed technique was then used for a preconcentration and elimination of NOD trace levels in different water matrices. The results showed that the WTAC was an effective adsorbent for the preconcentration and removal of NOD from the complex matrices.


Assuntos
Monitoramento Ambiental , Peptídeos Cíclicos/análise , Poluentes Químicos da Água/análise , Adsorção , Carvão Vegetal/química , Água Doce/química , Água do Mar/química , Águas Residuárias/química , Purificação da Água/métodos
19.
Arch Virol ; 165(6): 1397-1407, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32307604

RESUMO

A new cyanophage, S-B05, infecting a phycoerythrin-enriched (PE-type) Synechococcus strain was isolated by the liquid infection method, and its morphology and genetic features were examined. Phylogenetic analysis and morphological observation confirmed that S-B05 belongs to the family Myoviridae of the order Caudovirales. Its genome was fully sequenced, and found to be 208,857 bp in length with a G + C content of 39.9%. It contained 280 potential open reading frames and 123 conserved domains. Ninety-eight functional genes responsible for cyanophage structuring and packaging, DNA replication and regulation, and photosynthesis were identified, as well as genes encoding 172 hypothetical proteins. The genome of S-B05 is most similar to that of Prochlorococcus phage P-TIM68. Homologues of open reading frames of S-B05 can be found in various marine environments, as revealed by comparison of the S-B05 genome sequence to sequences in marine viral metagenomic databases. The presence of auxiliary metabolic genes (AMGs) related to photosynthesis, carbon metabolism, and phosphorus assimilation, as well as the phylogenetic relationships based on AMGs and the complete genome sequence, reflect the phage-host interaction mechanism or the specific adaptation strategy of the host to environmental conditions. The genome sequence information reported here will provide an important basis for further study of the adaptive evolution and ecological role of cyanophages and their hosts in the marine environment.


Assuntos
Genoma Viral , Myoviridae/classificação , Myoviridae/isolamento & purificação , Água do Mar/virologia , Synechococcus/virologia , Composição de Bases , Sequência de Bases , China , Especificidade de Hospedeiro , Metagenômica , Myoviridae/ultraestrutura , Fases de Leitura Aberta , Oceano Pacífico , Filogenia , Microbiologia da Água , Sequenciamento Completo do Genoma
20.
Environ Monit Assess ; 192(5): 276, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32274591

RESUMO

To assess the fate and behavior of engineered nanoparticles in the environment, it is important to examine the physicochemical and toxicological transformation of nanoparticles as they age in seawater. In this study, we investigated how aging and seawater conditions altered the physiochemical structure of nanoparticles and affected their interactions with bacteria. For this purpose, zinc oxide nanoparticles were aged under different seawater conditions by keeping them in 1%, 10%, and 100% seawater for 1 day and 20 days. The main physicochemical parameters (surface chemistry, chemical composition, particle size, and zeta potential) and toxicity of aged nanoparticles towards gram-negative Pseudomonas aeruginosa and gram-positive Staphylococcus aureus were examined. The results indicated that aged zinc oxide nanoparticles in various concentrations of seawater changed their surface chemistry, chemical composition, particle size, and zeta potentials. Growth inhibition results were observed in that the inhibition of gram-negative (Pseudomonas aeruginosa) bacteria was higher compared with the gram-positive (Staphylococcus aureus) bacteria, and Staphylococcus aureus activated with the aged zinc oxide nanoparticles. Also, the results showed that the key biochemical factors affected by the aging and seawater concentration.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Antibacterianos , Bactérias , Monitoramento Ambiental , Água do Mar/química , Água do Mar/microbiologia , Microbiologia da Água
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