RESUMO
As a new electrochemical technology, capacitive deionization (CDI) has been increasingly applied in environmental water treatment and seawater desalination. In this study, functional groups modified porous hollow carbon (HC) were synthesized as CDI electrode material for removing Na+ and Cl- in salty water. Results showed that the average diameter of HC was approximately 180 nm, and the infrared spectrum showed that its surface was successfully modified with sulfonic and amino groups, respectively. The sulfonic acid functionalized HC (HC-S) showed better electrochemical and desalting performance than the amino-functionalized HC (HCN), with a maximum Faradic capacity of 287.4 F/g and an adsorptive capacity of 112.97 mg/g for NaCl. Additionally, 92.63% capacity retention after 100 adsorption/desorption cycles demonstrates the excellent stability of HC-S. The main findings prove that HC-S is viable as an electrode material for desalination by high-performance CDI applications.
Assuntos
Carbono , Eletrodos , Purificação da Água , Purificação da Água/métodos , Carbono/química , Porosidade , Adsorção , Água do Mar/química , Salinidade , Cloreto de Sódio/químicaRESUMO
Increasing nitrogen and phosphorus discharge and decreasing sediment input have made silicon (Si) a limiting element for diatoms in estuaries. Disturbances in nutrient structure and salinity fluctuation can greatly affect metal uptake by estuarine diatoms. However, the combined effects of Si and salinity on metal accumulation in these diatoms have not been evaluated. In this study, we aimed to investigate how salinity and Si availability combine to influence the adsorption of metals by a widely distributed diatom Phaeodactylum tricornutum. Our data indicate that replete Si and low salinity in seawater can enhance cadmium and copper adsorption onto the diatom surface. At the single-cell level, surface potential was a dominant factor determining metal adsorption, while surface roughness also contributed to the higher metal loading capacity at lower salinities. Using a combination of non-invasive micro-test technology, atomic force microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy, we demonstrate that the diversity and abundance of the functional groups embedded in diatom cell walls vary with salinity and Si supply. This results in a change in the cell surface potential and transient metal influx. Our study provides novel mechanisms to explain the highly variable metal adsorption capacity of a model estuarine diatom.
Assuntos
Diatomáceas , Salinidade , Silício , Poluentes Químicos da Água , Adsorção , Silício/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Estuários , Água do Mar/química , Metais/químicaRESUMO
The ocean serves as a repository for various types of artificial nanoparticles. Nanoplastics (NPs) and nano zinc oxide (nZnO), which are frequently employed in personal care products and food packaging materials, are likely simultaneously released and eventually into the ocean with surface runoff. Therefore, their mutual influence and shared destiny in marine environment cannot be ignored. This study examined how nanomaterials interacted and transported through sea sand in various salinity conditions. Results showed that NPs remained dispersed in brine, while nZnO formed homoaggregates. In seawater of 35 practical salinity units (PSU), nZnO formed heteroaggregates with NPs, inhibiting NPs mobility and decreasing the recovered mass percentage (Meff) from 24.52% to 12.65%. In 3.5 PSU brackish water, nZnO did not significantly aggregate with NPs, and thus barely affected their mobility. However, NPs greatly enhanced nZnO transport with Meff increasing from 14.20% to 25.08%, attributed to the carrier effect of higher mobility NPs. Cotransport from brackish water to seawater was simulated in salinity change experiments and revealed a critical salinity threshold of 10.4 PSU, below which the mobility of NPs was not affected by coexisting nZnO and above which nZnO strongly inhibited NP transport. This study highlights the importance of considering the mutual influence and shared destiny of artificial nanoparticles in the marine environment and how their interaction and cotransport are dependent on changes in seawater salinity.
Assuntos
Águas Salinas , Salinidade , Água do Mar , Poluentes Químicos da Água , Óxido de Zinco , Óxido de Zinco/química , Água do Mar/química , Águas Salinas/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Porosidade , Microplásticos , Modelos Químicos , Nanopartículas Metálicas/químicaRESUMO
With advancements in naval warfare, the number and severity of seawater injuries have skyrocketed, necessitating effective seawater immersion (SWI) wound management. The unique marine pathogens, salinity, low temperature and alkalinity of seawater are the main environmental factors that can influence SWI wound healing. The current treatment strategy for SWI wounds follows a standard protocol based on terrestrial wound conditions, neglecting seawater conditions. The key requirements for ideal SWI treatment include good adhesion to the wound surface to minimize further exposure to seawater, enhanced wound healing properties to minimize wound healing time and antibacterial properties to prevent infections from marine pathogens. Current SWI wound-specific treatments range from elaborate techniques like vacuum-sealed drainage and vacuum-assisted closure for severe blast injuries to simple application of hydrogels or collagen dressings for minor injuries. This review discusses the current status and development of various treatment modalities for SWI wounds. The development of these treatment strategies and an understanding of their mechanisms of action make us better prepared to manage and treat SWI injuries.
Assuntos
Água do Mar , Cicatrização , Humanos , Imersão , Ferimentos e Lesões/terapia , Tratamento de Ferimentos com Pressão Negativa/métodos , BandagensRESUMO
The use of biosurfactants represents a promising technology for remediating hydrocarbon pollution in the environment. This study evaluated a highly effective biosurfactant strain-Bacillus cereus GX7's ability to produce biosurfactants from industrial and agriculture organic wastes. Bacillus cereus GX7 showed poor utilization capacity for oil soluble organic waste but effectively utilized of water- soluble organic wastes such as starch hydrolysate and wheat bran juice as carbon sources to enhance biosurfactant production. This led to significant improvements in surface tension and emulsification index. Corn steep liquor was also effective as a nitrogen source for Bacillus cereus GX7 in biosurfactant production. The biosurfactants produced by strain Bacillus cereus GX7 demonstrated a remediation effect on oily beach sand, but are slightly inferior to chemical surfactants. Inoculation with Bacillus cereus GX7 (70.36%) or its fermentation solution (94.38%) effectively enhanced the degradation efficiency of diesel oil in polluted seawater, surpassing that of indigenous degrading bacteria treatments (57.62%). Moreover, inoculation with Bacillus cereus GX7's fermentation solution notably improved the community structure by increasing the abundance of functional bacteria such as Pseudomonas and Stenotrophomonas in seawater. These findings suggest that the Bacillus cereus GX7 as a promising candidate for bioremediation of petroleum hydrocarbons.
Assuntos
Bacillus cereus , Biodegradação Ambiental , Fermentação , Hidrocarbonetos , Água do Mar , Tensoativos , Bacillus cereus/metabolismo , Tensoativos/metabolismo , Hidrocarbonetos/metabolismo , Água do Mar/microbiologia , Petróleo/metabolismo , Tensão SuperficialRESUMO
A Gram-stain-negative, yellow-pigmented, and strictly aerobic bacterium, designated as strain MSW5T, was isolated from seawater of the Yellow Sea in South Korea. The cells were non-motile rods exhibiting oxidase- and catalase-positive activities. Growth was observed at 15-25 °C (optimum, 25 °C) and pH 5.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 1.0-5.0% (w/v) NaCl (optimum, 2.0%). Menaquinone-6 was the sole respiratory quinone, and iso-C15â:â0, summed feature 3 (C16â:â1 ω7c and/or C16â:â1 ω6c), iso-C15â:â0 3-OH, and C15â:â1 ω6c were the major cellular fatty acids. Major polar lipids included phosphatidylethanolamine, two unidentified aminolipids, and three unidentified lipids. Phylogenetic analyses based on 16S rRNA gene sequences and 92 concatenated core protein sequences revealed that strain MSW5T formed a distinct lineage within the genus Polaribacter. The genome of strain MSW5T was 3582 kb in size with a 29.1 mol% G+C content. Strain MSW5T exhibited the highest similarity to Polaribacter atrinae WP25T, with a 97.9% 16S rRNA gene sequence similarity. However, the average nucleotide identity and digital DNA-DNA hybridization values were 79.4 and 23.3%, respectively, indicating that strain MSW5T represents a novel species. Based on its phenotypic, chemotaxonomic, and phylogenetic characteristics, strain MSW5T is proposed to represent a novel species, with the name Polaribacter ponticola sp. nov. The type strain is MSW5T (=KACC 22340T=NBRC 116025T). In addition, whole genome sequence comparisons and phenotypic features suggested that Polaribacter sejongensis and Polaribacter undariae belong to the same species, with P. undariae proposed as a later heterotypic synonym of P. sejongensis. An emended description of Polaribacter sejongensis is also proposed.
Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Filogenia , RNA Ribossômico 16S , Água do Mar , Análise de Sequência de DNA , Vitamina K 2 , RNA Ribossômico 16S/genética , Ácidos Graxos/análise , Água do Mar/microbiologia , República da Coreia , DNA Bacteriano/genética , Vitamina K 2/análogos & derivados , Vitamina K 2/análise , Fosfatidiletanolaminas , Hibridização de Ácido Nucleico , Bacteroidetes/genética , Bacteroidetes/classificação , Bacteroidetes/isolamento & purificação , Fosfolipídeos/análise , Fosfolipídeos/químicaRESUMO
Lipids comprise a significant fraction of sinking organic matter in the ocean and play a crucial role in the carbon cycle. Despite this, our understanding of the processes that control lipid degradation is limited. We combined nanolipidomics and imaging to study the bacterial degradation of diverse algal lipid droplets and found that bacteria isolated from marine particles exhibited distinct dietary preferences, ranging from selective to promiscuous degraders. Dietary preference was associated with a distinct set of lipid degradation genes rather than with taxonomic origin. Using synthetic communities composed of isolates with distinct dietary preferences, we showed that lipid degradation is modulated by microbial interactions. A particle export model incorporating these dynamics indicates that metabolic specialization and community dynamics may influence lipid transport efficiency in the ocean's mesopelagic zone.
Assuntos
Bactérias , Metabolismo dos Lipídeos , Oceanos e Mares , Fitoplâncton , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Gotículas Lipídicas/metabolismo , Interações Microbianas , Microbiota , Água do Mar/microbiologia , Água do Mar/química , Fitoplâncton/metabolismoRESUMO
Marine bacteria cooperate to degrade lipids in sinking particulate organic matter.
Assuntos
Organismos Aquáticos , Bactérias , Metabolismo dos Lipídeos , Água do Mar , Organismos Aquáticos/metabolismo , Bactérias/metabolismo , Bactérias/genética , Água do Mar/microbiologia , Água do Mar/químicaRESUMO
Climate change is causing ocean warming (OW) and increasing the frequency, intensity, and duration of extreme weather events, including Marine Heat Waves (MHWs). Both OW and MHWs pose a significant threat to marine ecosystems and marine organisms, including oysters, oyster reefs and farmed oysters. We investigated the survival and growth of juveniles of two commercial species of oyster, the Sydney rock oyster, Saccostrea glomerata, and the Pacific oyster, Crassostrea gigas, to elevated seawater temperatures reflecting a moderate and an extreme MHW in context with recent MHWs and beyond. The survival and size of Pacific oysters to moderate MHWs (22-32 °C; 14 days) was greater than that for Sydney rock oysters (24-32 °C; 15 days). While survival and growth of both species was significantly impacted by extreme MHWs (29-38 °C; 5-6 days), Sydney rock oysters were found to survive greater temperatures compared to the Pacific oyster. Overall, this study found that Pacific oyster juveniles were more tolerant of a moderate MHW, while Sydney rock oyster juveniles were more resilient to extreme MHWs. These differences in thermal tolerance may have consequences for aquaculture and coexistence of both species in their intertidal and latitudinal distributions along the south-eastern Australian coastline.
Assuntos
Mudança Climática , Ostreidae , Animais , Ostreidae/crescimento & desenvolvimento , Ostreidae/fisiologia , Ecossistema , Oceanos e Mares , Temperatura Alta , Espécies Introduzidas , Água do Mar , Crassostrea/crescimento & desenvolvimento , Crassostrea/fisiologiaRESUMO
Casuarina equisetifolia trees are used as windbreaks in subtropical and tropical coastal zones, while C. equisetifolia windbreak forests can be degraded by seawater atomization (SA) and seawater encroachment (SE). To investigate the mechanisms underlying the response of C. equisetifolia to SA and SE stress, the transcriptome and metabolome of C. equisetifolia seedlings treated with control, SA, and SE treatments were analyzed. We identified 737, 3232, 3138, and 3899 differentially expressed genes (SA and SE for 2 and 24 h), and 46, 66, 62, and 65 differentially accumulated metabolites (SA and SE for 12 and 24 h). The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that SA and SE stress significantly altered the expression of genes related to plant hormone signal transduction, plant-pathogen interaction, and starch and sucrose metabolism pathways. The accumulation of metabolites associated with the biosynthetic pathways of phenylpropanoid and amino acids, as well as starch and sucrose metabolism, and glycolysis/gluconeogenesis were significantly altered in C. equisetifolia subjected to SA and SE stress. In conclusion, C. equisetifolia responds to SA and SE stress by regulating plant hormone signal transduction, plant-pathogen interaction, biosynthesis of phenylpropanoid and amino acids, starch and sucrose metabolism, and glycolysis/gluconeogenesis pathways. Compared with SA stress, C. equisetifolia had a stronger perception and response to SE stress, which required more genes and metabolites to be regulated. This study enhances our understandings of how C. equisetifolia responds to two types of seawater stresses at transcriptional and metabolic levels. It also offers a theoretical framework for effective coastal vegetation management in tropical and subtropical regions.
Assuntos
Água do Mar , Estresse Fisiológico , Estresse Fisiológico/genética , Água do Mar/química , Transcriptoma , Regulação da Expressão Gênica de Plantas , Metaboloma , Plântula/genética , Plântula/fisiologia , Metabolômica , MultiômicaRESUMO
Human activity is generating an excess of atmospheric CO2, resulting in what we know as ocean acidification, which produces changes in marine ecosystems. Until recently, most of the research in this area had been done under small-scale, laboratory conditions, using few variables, few species and few life cycle stages. These limitations raise questions about the reproducibility of the environment and about the importance of indirect effects and synergies in the final results of these experiments. One way to address these experimental problems is by conducting studies in situ, in natural areas where expected future pH conditions already occur, such as CO2 vent systems. In the present work, we compile and discuss the latest research carried out in these natural laboratories, with the objective to summarize their advantages and disadvantages for research to improve these investigations so they can better help us understand how the oceans of the future will change.
Assuntos
Dióxido de Carbono , Oceanos e Mares , Água do Mar , Concentração de Íons de Hidrogênio , Água do Mar/química , Ecossistema , Animais , Mudança Climática , Acidificação dos OceanosRESUMO
Natural acidified marine systems (ASs) are environments with relatively low pH levels due to natural causes such as volcanic activity, geochemical reactions, and biological processes. These systems act as natural laboratories for the study of the effects of ocean acidification, allowing for the observation of long-term ecological and evolutionary responses. Understanding these systems is crucial for predicting the effects of anthropogenic ocean acidification (OA) on marine ecosystems. There are 23 ASs in which scientific research has shown significant parallelisms in their results worldwide, such as the disappearance of calcareous organisms and the loss of species with key ecological functions under OA conditions. Future research should emphasize continuous collaboration among teams, as well as public access to oceanographic and biological data along with the monitoring of environmental variables at each AS. To preserve these areas, it is imperative to employ non-destructive methods and protect them as human heritage sites.
Assuntos
Ecossistema , Oceanos e Mares , Água do Mar , Concentração de Íons de Hidrogênio , Animais , Água do Mar/química , Organismos Aquáticos , Monitoramento AmbientalRESUMO
The biological pump supplies carbon to the oceans' interior, driving long-term carbon sequestration and providing energy for deep-sea ecosystems1,2. Its efficiency is set by transformations of newly formed particles in the euphotic zone, followed by vertical flux attenuation via mesopelagic processes3. Depth attenuation of the particulate organic carbon (POC) flux is modulated by multiple processes involving zooplankton and/or microbes4,5. Nevertheless, it continues to be mainly parameterized using an empirically derived relationship, the 'Martin curve'6. The derived power-law exponent is the standard metric used to compare flux attenuation patterns across oceanic provinces7,8. Here we present in situ experimental findings from C-RESPIRE9, a dual particle interceptor and incubator deployed at multiple mesopelagic depths, measuring microbially mediated POC flux attenuation. We find that across six contrasting oceanic regimes, representing a 30-fold range in POC flux, degradation by particle-attached microbes comprised 7-29 per cent of flux attenuation, implying a more influential role for zooplankton in flux attenuation. Microbial remineralization, normalized to POC flux, ranged by 20-fold across sites and depths, with the lowest rates at high POC fluxes. Vertical trends, of up to threefold changes, were linked to strong temperature gradients at low-latitude sites. In contrast, temperature played a lesser role at mid- and high-latitude sites, where vertical trends may be set jointly by particle biochemistry, fragmentation and microbial ecophysiology. This deconstruction of the Martin curve reveals the underpinning mechanisms that drive microbially mediated POC flux attenuation across oceanic provinces.
Assuntos
Organismos Aquáticos , Ciclo do Carbono , Carbono , Ecossistema , Oceanos e Mares , Água do Mar , Animais , Carbono/metabolismo , Sequestro de Carbono , Água do Mar/química , Água do Mar/microbiologia , Zooplâncton/metabolismo , Temperatura , Organismos Aquáticos/metabolismoRESUMO
Carotenoids are natural pigments utilized as colourants and antioxidants across food, pharmaceutical and cosmetic industries. They exist in carbon chain lengths of C30, C40, C45 and C50, with C40 variants being the most common. Bacterioruberin (BR) and its derivatives are part of the less common C50 carotenoid group, synthesized primarily by halophilic archaea. This study analysed the compositional characteristics of BR extract (BRE) isolated from 'Haloferax marinum' MBLA0078, a halophilic archaeon isolated from seawater near Yeoungheungdo Island in the Republic of Korea, and investigated its antioxidant activity and protective effect on lipopolysaccharide (LPS)-induced C2C12 myotube atrophy. The main components of BRE included all-trans-BR, monoanhydrobacterioruberin, 2-isopentenyl-3,4-dehydrorhodopin and all-trans-bisanhydrobacterioruberin. BRE exhibited higher antioxidant activity and DNA nicking protection activity than other well-known C40 carotenoids, such as ß-carotene, lycopene and astaxanthin. In C2C12 myotubes, LPS treatment led to a reduction in myotube diameter and number, as well as the hypertranscription of the muscle-specific ubiquitin ligase MAFbx and MuRF1. BRE mitigated these changes by activating the Akt/mTOR pathway. Furthermore, BRE abolished the elevated cellular reactive oxygen species levels and the inflammation response induced by LPS. This study demonstrated that 'Hfx. marinum' is an excellent source of natural microbial C50 carotenoids with strong antioxidant capacity and may offer potential protective effects against muscle atrophy.
Assuntos
Antioxidantes , Carotenoides , Lipopolissacarídeos , Fibras Musculares Esqueléticas , Antioxidantes/farmacologia , Animais , Camundongos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Linhagem Celular , Carotenoides/farmacologia , República da Coreia , Água do Mar/microbiologiaRESUMO
The Changjiang Estuary and adjacent East China Sea are well-known hypoxic aquatic environments. Eutrophication-driven hypoxia frequently occurs in coastal areas, posing a major threat to the ecological environment, including altering community structure and metabolic processes of marine organisms, and enhancing diversion of energy shunt into microbial communities. However, the responses of microbial communities and their metabolic pathways to coastal hypoxia remain poorly understood. Here, we studied the microbial communities collected from spatiotemporal samplings using metagenomic sequencing in the Changjiang Estuary and adjacent East China Sea. This generated 1.31 Tbp of metagenomics data, distributed across 103 samples corresponding to 8 vertical profiles. We further reported 1,559 metagenome-assembled genomes (MAGs), of which 508 were high-quality MAGs (Completeness > 90% and Contamination < 10%). Phylogenomic analysis classified them into 181 archaeal and 1,378 bacterial MAGs. These results provided a valuable metagenomic dataset available for further investigation of the effects of hypoxia on marine microorganisms.
Assuntos
Archaea , Metagenoma , China , Archaea/genética , Bactérias/genética , Bactérias/classificação , Oxigênio , Água do Mar/microbiologia , Filogenia , Metagenômica , Oceanos e Mares , MicrobiotaRESUMO
In nature, the number of genome or chromosome copies within cells (ploidy) can vary between species and environmental conditions, potentially influencing how organisms adapt to changing environments. Although ploidy levels cannot be easily determined by standard genome sequencing, understanding ploidy is crucial for the quantitative interpretation of molecular data. Cyanobacteria are known to contain haploid, oligoploid, and polyploid species. The smallest cyanobacteria, picocyanobacteria (less than 2 µm in diameter), have a widespread distribution ranging from marine to freshwater environments, contributing significantly to global primary production. In this study, we determined the ploidy level of genetically and physiologically diverse brackish picocyanobacteria isolated from the Baltic Sea using a qPCR assay targeting the rbcL gene. The strains contained one to four genome copies per cell. The ploidy level was not linked with phylogeny based on the identity of the 16S rRNA gene. The variation of ploidy among the brackish strains was lower compared to what has been reported for freshwater strains and was more similar to what has been reported for marine strains. The potential ecological advantage of polyploidy among picocyanobacteria has yet to be described. Our study highlights the importance of considering ploidy to interpret the abundance and adaptation of brackish picocyanobacteria.
Assuntos
Cianobactérias , Filogenia , Ploidias , RNA Ribossômico 16S , Água do Mar , Água do Mar/microbiologia , Cianobactérias/genética , Cianobactérias/classificação , Cianobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Oceanos e MaresRESUMO
Climate change is causing increased coastal freshening in Antarctica, leading to reduced salinity. For Antarctica's endemic echinoderms, adapted to the stable polar environment, the impact of rapid reductions in coastal salinity on physiology and behaviour is currently unknown. Six common Antarctic echinoderms (the sea urchin Sterechinus neumayeri; the sea star Odontaster validus; the brittle star Ophionotus victoriae; and three sea cucumbers Cucumaria georgiana, Echinopsolus charcoti and Heterocucumis steineni), were directly transferred from ambient salinity (34.5) to a range of salinity dilutions (29-9) for 24 h. All species showed reduced activity and the establishment of a temporary osmotic gradient between coelomic fluid and external seawater. Most species exhibited a depression in oxygen consumption across tolerated salinities; however, at very low salinities that later resulted in mortality, oxygen consumption increased to levels comparable to those at ambient. Low salinity tolerance varied substantially between species, with O. victoriae being the least tolerant (24 h LC50 (lethal for 50% of animals) = 19.9) while E. charcoti and C. georgiana demonstrated the greatest tolerance (24 h LC50 = 11.5). These findings demonstrate the species-specific response of Antarctica's endemic echinoderms to short-term hypoosmotic salinity events, providing valuable insight into this phylum's ability to respond to an underreported impact of climate change.
Assuntos
Mudança Climática , Equinodermos , Salinidade , Animais , Regiões Antárticas , Equinodermos/fisiologia , Estresse Salino , Consumo de Oxigênio , Estrelas-do-Mar/fisiologia , Água do Mar/químicaRESUMO
Polychlorinated biphenyl compounds (PCBs) are industrial chemicals whose production was discontinued in the early nineties in most countries. Sill, PCBs are detectable in pristine and remote locations. Occurrence in regions such as Southern Oceans and Antarctica are influenced by the global, and regional, cycling. Here, we studied the surface and deep ocean distribution of indicator- and dioxin-like PCB congeners in the Southern Indian Ocean (SIO), and the coast of Antarctica (COA) during the tenth Indian Southern Ocean Expedition (SOE-10), December 2017-February 2018. ∑21PCBs in SIO surface waters ranged from 3.8 to 167.1 pg L-1 (average ± standard deviation: 35.7 ± 48.4 pg L-1), and in COA from 1.0 to 41.8 pg L-1 (13.8 ± 12.7 pg L-1), respectively. A noticeable gradient was observed, with higher PCBs levels in northern latitudes than southern latitudes in the SIO, and higher levels in the eastern longitudes compared to western longitudes in the COA. Results suggest the influence of secondary sources, or re-emission, of PCBs in the Southern Oceans and Antarctica. Both regions showed notable PCB levels in surface and deep waters (up to 1000 m) due to ongoing surface sources and remineralization processes in deeper waters. Multimedia modeling with the global model (BETR-Global) suggests the SIO act as a net sink for PCBs in the ocean.
Assuntos
Monitoramento Ambiental , Bifenilos Policlorados , Água do Mar , Poluentes Químicos da Água , Bifenilos Policlorados/análise , Regiões Antárticas , Poluentes Químicos da Água/análise , Oceano Índico , Água do Mar/químicaRESUMO
Both petroleum hydrocarbons (PHCs) from oil pollution and colored dissolved organic matter (CDOM) have great influences on the marine microbial community as carbon source factors. However, their combined effects and the specific influence patterns have been kept unclear. This study selected the northeastern South China Sea (NSCS), a typical oil contaminated area, and investigated the characteristics of oil-degrading microbiota in the seawaters by high-throughput sequencing and the relationships with PHCs and CDOM as well as other environmental factors. The results showed the oil pollution had induced the enrichment of oil-degrading bacteria and oil-degrading functional genes, resulting in the core function of oil-degrading microbiota for shaping the microbial community. The Mantel test indicated carbon source factors played the dominant role in shaping the oil-degrading microbiota, compared with geographical distance and other noncarbon source factors. The influence patterns and strength of PHCs and CDOM on oil-degrading microbiota were further comprehensively analyzed. PHCs played a driving role in the differentiation of oil-degrading microbiota, while CDOM played a stabilizing role for the community similarity. The constructed structural equation model confirmed their distinct influence patterns and also explored the mediating effects of bulk organic carbon. This work not only revealed the important impact of oil pollution on marine microbial communities, but also made people realize the self-regulation ability of the marine environment through the endogenous organic matter.
Assuntos
Hidrocarbonetos , Microbiota , Petróleo , Poluentes Químicos da Água , Petróleo/metabolismo , Hidrocarbonetos/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/análise , China , Água do Mar/microbiologia , Poluição por Petróleo , Biodegradação Ambiental , Bactérias/metabolismo , Bactérias/classificação , Monitoramento AmbientalRESUMO
Understanding the environmental fate of biodegradable plastics in aquatic systems is crucial, given the alarming amount of plastic waste and microplastic particles transported through aquatic pathways. In particular, there is a need to analyze the biodegradation of commercialized biodegradable plastics upon release from wastewater treatment plants into natural aquatic systems. This study investigates the biodegradation behaviors of poly(butylene adipate terephthalate) (PBAT) and poly(vinyl alcohol) (PVA) in wastewater, freshwater, and seawater. Biodegradation of PBAT and PVA assessed through biochemical oxygen demand (BOD) experiments and microcosm tests revealed that the type of aquatic system governs the biodegradation behaviors of each plastic, with the highest biodegradation rate achieved in wastewater for both PBAT and PVA (25.6 and 32.2 % in 30 d, respectively). Plastic release pathway from wastewater into other aquatic systems simulated by sequential incubation in different microcosms suggested that PBAT exposed to wastewater and freshwater before reaching seawater was more prone to degradation than when directly exposed to seawater. On the other hand, PVA displayed comparable biodegradation rate regardless of whether it was directly exposed to seawater or had passed through other environments beforehand. Metagenome amplicon sequencing of 16S rRNA genes revealed distinct community shifts dependent on the type of plastics in changing environments along the simulated aquatic pathway. Several bacterial species putatively implicated in the biodegradation of PBAT and PVA are discussed. Our findings underscore the significant influence of pollution routes on the biodegradation of PBAT and PVA, highlighting the potential for wastewater treatment to facilitate rapid degradation compared to direct exposure to pristine aquatic environments.