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1.
J Environ Sci (China) ; 149: 254-267, 2025 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39181640

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/química
2.
J Environ Sci (China) ; 148: 364-374, 2025 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-39095171

RESUMO

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/química
3.
J Environ Sci (China) ; 148: 541-552, 2025 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-39095187

RESUMO

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/química
4.
Harmful Algae ; 138: 102686, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39244229

RESUMO

Several Dinophysis species can produce potent lipophilic toxins that pose a risk to human health when contaminated seafood is consumed, especially filter-feeding bivalve mussels. In the mussel farms of the Northwestern Adriatic Sea, seawater and seafood are regularly monitored for the presence of Dinophysis species and their associated toxins, but the current methodological approaches, such as light microscopy determinations, require a long time to make results available to local authorities. A molecular qPCR-based assay can be used to quantify various toxic Dinophysis species in a shorter timeframe. However, this approach is not currently employed in official testing activities. In this study, field samples were collected monthly or bi-weekly over one year from various mussel farms along the Northwestern Adriatic coast. The abundance of Dinophysis species in the seawater was determined using both traditional microscopy and qPCR assays. In addition, the concentration of lipophilic toxins for DSP in mussel flesh was quantified using LC-MS/MS focusing on the okadaic acid group. Dinophysis spp. site-specific single cells were isolated and analysed by qPCR yielding a mean rDNA copy number per cell of 1.21 × 104 ± 1.81 × 103. The qPCR assay gave an efficiency of 98 % and detected up to 10 copies of the rDNA target gene. The qPCR and light microscopy determinations in environmental samples showed a significant positive correlation (Spearman rs = 0.57, p-value < 0.001) with a ratio of 2.24 between the two quantification methods, indicating that light microscopy estimates were generally 44.6 % lower than those obtained by the qPCR assay. The qPCR approach showed several advantages such as rapidity, sensitivity and efficiency over conventional microscopy analysis, showing its potential future role in phytoplankton monitoring under the Official Controls Regulations for shellfish.


Assuntos
Bivalves , Dinoflagellida , Animais , Dinoflagellida/genética , Dinoflagellida/classificação , Bivalves/química , Monitoramento Ambiental/métodos , Toxinas Marinhas/análise , Água do Mar/química , Aquicultura
5.
Glob Chang Biol ; 30(9): e17501, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39239976

RESUMO

Otoliths are frequently used as proxies to examine the impacts of climate change on fish growth in marine and freshwater ecosystems worldwide. However, the large sensitivity differences in otolith growth responses to typical changing environmental factors (i.e., temperature and CO2 concentration), coupled with unclear drivers and potential inconsistencies with fish body growth, fundamentally challenge the reliability of such otolith applications. Here, we performed a global meta-analysis of experiments investigating the direct effects of warming (297 cases) and CO2 acidification (293 cases) on fish otolith growth and compared them with fish body growth responses. Hierarchical models were used to assess the overall effect and quantify the influence of nine explanatory factors (e.g., fish feeding habit, life history stage, habitat type, and experimental amplitude and duration). The overall effects of warming and acidification on otolith growth were positive and significant, and the effect size of warming (effect size = 0.4003, otolith size of the treatment group increased by 49.23% compared to that of the control group) was larger than that of acidification (0.0724, 7.51%). All factors examined contributed to the heterogeneity of effect sizes, with larger responses commonly observed in carnivorous fish, marine species, and young individuals. Warming amplitudes and durations and acidification amplitudes increased the effect sizes, while acidification durations decreased the effect sizes. Otolith growth responses were consistent with, but greater than, fish body growth responses under warming. In contrast, fish body growth responses were not significant under acidification (effect size = -0.0051, p = .6185) and thus cannot be estimated using otoliths. Therefore, our study highlights that the reliability of applying otoliths to examine climate change impacts is likely varied, as the sensitivity of otolith growth responses and the consistency between the growth responses of otoliths and fish bodies are context-dependent.


Assuntos
Dióxido de Carbono , Mudança Climática , Peixes , Membrana dos Otólitos , Animais , Membrana dos Otólitos/crescimento & desenvolvimento , Peixes/crescimento & desenvolvimento , Peixes/fisiologia , Dióxido de Carbono/metabolismo , Dióxido de Carbono/análise , Concentração de Íons de Hidrogênio , Ecossistema , Temperatura , Água do Mar/química
6.
Ying Yong Sheng Tai Xue Bao ; 35(7): 1944-1950, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39233424

RESUMO

Identifying and quantifying water nitrate pollution is crucial for managing aquatic environment of a bay. Dongshan Bay, a significant semi-enclosed bay in the southeastern coastal area of Fujian Province, features mangrove and coral reef ecosystems at its estuary and bay mouth, respectively. Dongshan Bay is impacted by human activities such as mariculture. We quantified and analyzed nitrate pollution status in the surface waters of Dongshan Bay by measuring physicochemical parameters, stable isotopes (δ15N-NO3-, δ18O-NO3- and δ15N-NH4+) of the surface waters, and using statistical methods including the MixSIAR isotope mixing model. The results showed that the concentrations of chlorophyll a and dissolved inorganic nitrogen in the surface waters exhibited a noticeable gradient change, decreasing from the estuary of the Zhangjiang River to the mouth of Dongshan Bay. The maximum concentrations of chlorophyll a, NH4+, NO3- and NO2- were 45.2 µg·L-1, 52.67 µmol·L-1, 379.2 µmol·L-1 and 3.93 µmol·L-1, respectively. The nitrogen and oxygen isotope values of NH4+ and NO3- in the surface waters showed significant spatial variations. According to the MixSIAR model results, nitrogen sources in the surface waters of Dongshan Bay were mainly freshwater inputs of the Zhangjiang River estuary, aquaculture wastewater, and groundwater. The freshwater input from the Zhangjiang River estuary contributed the most (25.2%), while aquaculture wastewater, groundwater and urban sewage accounted for 24.6%, 19.0%, and 15.1%, respectively. It is evident that freshwater input from the Zhangjiang River estuary is the primary source of nitrate in the surface waters of Dongshan Bay.


Assuntos
Baías , Monitoramento Ambiental , Nitratos , Isótopos de Nitrogênio , Água do Mar , Poluentes Químicos da Água , Nitratos/análise , China , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Isótopos de Nitrogênio/análise , Água do Mar/análise , Água do Mar/química , Clorofila/análise , Clorofila A/análise , Isótopos de Oxigênio/análise
7.
Sci Rep ; 14(1): 20688, 2024 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237565

RESUMO

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/fisiologia
8.
Microb Biotechnol ; 17(9): e70009, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39264362

RESUMO

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/microbiologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-39264709

RESUMO

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-C15 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15 : 0 3-OH, and C15 : 1 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/química
10.
Environ Microbiol Rep ; 16(5): e70005, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39285802

RESUMO

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 Mares
11.
Microbiome ; 12(1): 162, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39232839

RESUMO

BACKGROUND: The backbone of the eukaryotic tree of life contains taxa only found in molecular surveys, of which we still have a limited understanding. Such is the case of Picozoa, an enigmatic lineage of heterotrophic picoeukaryotes within the supergroup Archaeplastida, which has emerged as a significant component of marine microbial planktonic communities. To enhance our understanding of the diversity, distribution, and ecology of Picozoa, we conduct a comprehensive assessment at different levels, from assemblages to taxa, employing phylogenetic analysis, species distribution modeling, and ecological niche characterization. RESULTS: Picozoa was among the ten most abundant eukaryotic groups, found almost exclusively in marine environments. The phylum was represented by 179 Picozoa's OTU (pOTUs) placed in five phylogenetic clades. Picozoa community structure had a clear latitudinal pattern, with polar assemblages tending to cluster separately from non-polar ones. Based on the abundance and occupancy pattern, the pOTUs were classified into four categories: Low-abundant, Widespread, Polar, and Non-polar. We calculated the ecological niche of each of these categories. Notably, pOTUs sharing similar ecological niches were not closely related species, indicating a phylogenetic overdispersion in Picozoa communities. This could be attributed to competitive exclusion and the strong influence of the seasonal amplitude of variations in environmental factors, such as temperature, shaping physiological and ecological traits. CONCLUSIONS: Overall, this work advances our understanding of uncharted protists' evolutionary dynamics and ecological strategies. Our results highlight the importance of understanding the species-level ecology of marine heteroflagellates like Picozoa. The observed phylogenetic overdispersion challenges the concept of phylogenetic niche conservatism in protist communities, suggesting that closely related species do not necessarily share similar ecological niches. Video Abstract.


Assuntos
Eucariotos , Filogenia , Eucariotos/classificação , Eucariotos/genética , Biodiversidade , Organismos Aquáticos/classificação , Ecossistema , Água do Mar/parasitologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-39230938

RESUMO

Three Gram-stain-negative, aerobic, non-motile, chemoheterotrophic, short-rod-shaped bacteria, designated CDY1-MB1T, CDY2-MB3, and BDY3-MB2, were isolated from three marine sediment samples collected in the eastern Pacific Ocean. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains were related to the genus Aequorivita and close to the type strain of Aequorivita vitellina F4716T (with similarities of 98.0-98.1%). Strain CDY1-MB1T can grow at 15-37 °C (optimum 30 °C) and in media with pH 6-9 (optimum, pH 7), and tolerate up to 10% (w/v) NaCl. The predominant cellular fatty acids of strain CDY1-MB1T were iso-C15 : 0 (20.7%) and iso-C17 : 0 3-OH (12.8%); the sole respiratory quinone was menaquinone 6; the major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified polar lipids. The digital DNA-DNA hybridization/average nucleotide identity values between strains CDY1-MB1T, CDY2-MB3, and BDY3-MB2 and A. vitellina F4716T were 24.7%/81.6-81.7%, thereby indicating that strain CDY1-MB1T should represent a novel species of the genus Aequorivita. The genomic DNA G+C contents were 37.6 % in all three strains. Genomic analysis showed the presence of genes related to nitrogen and sulphur cycling, as well as metal reduction. The genetic traits of these strains indicate their possible roles in nutrient cycling and detoxification processes, potentially shaping the deep-sea ecosystem's health and resilience. Based upon the consensus of phenotypic and genotypic analyses, strain CDY1-MB1T should be classified as a novel species of the genus Aequorivita, for which the name Aequorivita flava sp. nov. is proposed. The type strain is CDY1-MB1T (=MCCC 1A16935T=KCTC 102223T).


Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Sedimentos Geológicos , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Água do Mar , Análise de Sequência de DNA , Vitamina K 2 , Sedimentos Geológicos/microbiologia , RNA Ribossômico 16S/genética , Ácidos Graxos/química , Oceano Pacífico , Vitamina K 2/análogos & derivados , Vitamina K 2/análise , DNA Bacteriano/genética , Água do Mar/microbiologia , Fosfolipídeos/análise , Fosfatidiletanolaminas , Flavobacteriaceae/isolamento & purificação , Flavobacteriaceae/genética , Flavobacteriaceae/classificação
13.
NPJ Biofilms Microbiomes ; 10(1): 78, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39227595

RESUMO

Protists are less studied for their role and diversity in ecosystems. Notably, protists have played and still play an important role in microbialites. Microbialites, or lithified microbial mats, represent the oldest evidence of fossil biofilms (~3.5 Gyr). Modern microbialites may offer a unique proxy to study the potential role of protists within a geological context. We examined protist diversity in freshwater (Kelly and Pavilion Lake in British Columbia, Canada) and marine (Highborne Cay, Bahamas) to hypersaline (Shark Bay, Australia) microbialites to decipher their geomicrobiological role. The freshwater microbialite communities were clearly distinct from their marine and hypersaline counterparts. Chlorophytes had higher numerical abundance in freshwater microbialites; whereas pennate diatoms dominated numerically in marine microbialites. Despite the differences, protists across ecosystems may have adopted similar roles and functions. We suggest a consistent biogeochemical role of protists across microbialites globally; but that salinity may shape protist composition and evolution in these ecosystems.


Assuntos
Ecossistema , Salinidade , Colúmbia Britânica , Eucariotos/classificação , Biodiversidade , Água Doce/microbiologia , Biofilmes/crescimento & desenvolvimento , Água do Mar/microbiologia , Austrália , Diatomáceas/crescimento & desenvolvimento , Sedimentos Geológicos/microbiologia
14.
Mar Pollut Bull ; 207: 116891, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39217869

RESUMO

Subsurface chlorophyll maxima (SCM) significantly contributes to oceanic primary productivity, emphasizing the need to study its dynamics and governing mechanisms. We used datasets from various platforms to investigate relationships between the SCM characteristics (SCM depth (ZSCM), SCM magnitude (Chlmax), SCM thickness (TSCM)) and environmental variables modulated by various physical processes in the Northern Indian Ocean (NIO). In the Arabian Sea (western NIO), seasonal processes like convective mixing and upwelling, primarily regulated the SCM characteristics. In the Bay of Bengal (eastern NIO), SCM characteristics were jointly influenced by fresh water influx, barrier layer formation, presence of eddies, and the propagation of Kelvin and Rossby waves. Any changes in these oceanic processes, potentially driven by climate change, could therefore impact oceanic primary production. Additionally, a positive association obtained between Chlmax and downward CO2 flux, while a shallower ZSCM, associated with higher concentrations of DMS, indicated SCM's role in regulating atmospheric gases.


Assuntos
Clorofila , Monitoramento Ambiental , Água do Mar , Clorofila/análise , Oceano Índico , Água do Mar/química , Mudança Climática , Estações do Ano
15.
J Environ Manage ; 369: 122279, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39217904

RESUMO

The shortage of food and freshwater sources threatens human health and environmental sustainability. Spirulina grown in seawater-based media as a healthy food is promising and environmentally friendly. This study used three machine learning techniques to identify important cultivation parameters and their hidden interrelationships and optimize the biomass yield of Spirulina grown in seawater-based media. Through optimization of hyperparameters and features, eXtreme Gradient Boosting, along with the recursive feature elimination (RFE) model demonstrated optimal performance and identified 28 important features. Among them, illumination intensity and initial pH value were critical determinants of biomass, which impacted other features. Specifically, high initial pH values (>9.0) mainly increased biomass but also increased nutrient sedimentation and ammonia (NH3) losses. Both batch and continuous additions could decrease nutrient losses by increasing their availability in the seawater-based media. When illumination intensity exceeded 200 µmol photons/m2/s, it amplified the growth of Spirulina by mitigating the light attenuation caused by a high initial inoculum level and counteracted the negative effect of low temperature (<25 °C). In large-scale cultivation, production efficiency would be reduced if illumination was not maintained at a high level. High salinity and sodium bicarbonate (NaHCO3) addition promoted carbohydrate accumulation, but suitable dilution could keep the required protein content in Spirulina with relatively low media and production costs. These findings reveal the interactive influence of cultivation parameters on biomass yield and help us determine the optimal cultivation conditions for large-scale cultivation of Spirulina-based seawater system based on a developed graphical user interface website.


Assuntos
Biomassa , Aprendizado de Máquina , Água do Mar , Spirulina , Spirulina/crescimento & desenvolvimento , Spirulina/metabolismo , Água do Mar/química
16.
Mar Pollut Bull ; 207: 116823, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39226820

RESUMO

Seven seawater polychlorinated biphenyls (PCBs) were measured in water (DAP), suspended particulate matter (SPM), and blue mussels (Mytilus edulis) collected from four beaches in northwest Portugal. PCBs were extracted using solid-phase-extraction, ultrasound-extraction and QuEChERS before GC-MS analysis. The two-year annual average concentrations of PCBs in DAP, SPM and the four-year analysis in mussels were âˆ¼ 4.4 ng/L, ∼15.9 µg/kg, and âˆ¼ 56.0 µg/kg. The results suggest higher concentrations of PCBs in summer for SPM and in spring for mussels, mainly those collected close to the Ave River estuary. The origins of PCBs remain uncertain. Risk assessment shows that PCBs in water are unlikely to harm local biota due to their low thyroid hormone toxicity equivalents (TEQ-TH; ∼1.4E-04 ng/L and âˆ¼ 4.1E-04 µg/kg) and on WHO toxicity equivalents (TEQ-WHO; ∼2.1E-05 ng/L and âˆ¼ 4.9E-05 µg/kg). However, the lifetime carcinogenic risk (LCR) for humans consuming local bivalves is concerning, as it exceeds 1.0E-06.


Assuntos
Monitoramento Ambiental , Mytilus edulis , Bifenilos Policlorados , Poluentes Químicos da Água , Bifenilos Policlorados/análise , Animais , Poluentes Químicos da Água/análise , Portugal , Oceano Atlântico , Humanos , Medição de Risco , Carcinógenos/análise , Água do Mar/química
17.
Mar Pollut Bull ; 207: 116905, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39241366

RESUMO

Seawater desalination is one of the most feasible technologies for producing fresh water to address the water scarcity scenario worldwide. However, environmental concerns about the potential impact of brine discharge on marine ecosystems hinder or delay the development of desalination projects. In addition, scientific knowledge is lacking about the impact of brine discharges on the South America Pacific coast where desalination, is being developed. This paper presents the first monitoring results of brine discharge influence areas from seawater reverse osmosis desalination plants (SWRO) on the South America Pacific coast, using Chile as case study. Our results indicate that the combination of favorable oceanographic conditions and diffusers, results in the rapid dilution of brine discharge on coastal ecosystems; showing a faster dilution than other SWRO plants in other regions, such as Mediterranean or Arabian Gulf, with similar production characteristics. Also, the increase in salinity over the natural salinity in the brine-discharge-affected area was <5 % in a radius of <100 m from the discharge points. Further, according to the published literature and on our monitoring results, we propose a number of considerations (environmental regulation, best scientifically tested measures, environmental requirements) to achieve a long-term sustainable desalination operation.


Assuntos
Salinidade , Água do Mar , Chile , Monitoramento Ambiental/métodos , Sais/análise , Osmose , Purificação da Água/métodos , Oceano Pacífico , Ecossistema
18.
Mar Pollut Bull ; 207: 116736, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39241372

RESUMO

This study systematically investigated the photo-aging of polyvinyl chloride (PVC) in deionized water, estuary water, and seawater. As the concentration of Cl- increases, the carbonyl index (CI) of PVC during photo aging also increases, indicating that Cl- plays a dominant role in PVC photoaging in the environment, which enhance carbonyl index and •OH radical accumulation. Unlike previous studies, this study discovered that halogen radicals were also generated during PVC aging. Compared to •OH radicals, halogen radicals exhibit stronger selectivity and are more conducive to the photo aging of PVC. Additionally, it was found that PVC shows specific toxicity to Paramecia caudatum at various concentrations both before and after aging, affecting the reproduction process of Paramecia caudatum. This study elucidates the mechanism by which anions in natural water bodies affect the rate of PVC aging, providing a scientific basis for understanding the photodegradation of MPs in the ocean.


Assuntos
Cloreto de Polivinila , Água do Mar , Raios Ultravioleta , Poluentes Químicos da Água , Cloreto de Polivinila/química , Água do Mar/química , Radicais Livres , Fotólise
19.
J Environ Manage ; 369: 122244, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39241600

RESUMO

Wind power has become an essential direction for transforming energy structures in energy-intensive seawater desalination under the dual goals of carbon peaking and carbon neutrality. In this study, the energy footprint of the case project is analyzed by combining the hybrid life cycle analysis and environmentally extended input-output modeling, which is compared with the traditional thermal desalination processes from the whole life cycle perspective. The analysis revealed that the total energy consumption of the seawater desalination driven by wind power generation can be reduced by 79.77% compared with the traditional thermal drive mode under the same water production scale. Although the energy consumption in the construction phase accounts for 24.97% of the total, the energy consumption per unit of water production can be reduced by about 80% after adopting wind power technologies. The payback period is 7.2 years, that is, the energy consumption can be balanced after around 7 years during the operation phase. The results showed that the wind-driven seawater desalination system can significantly decrease the energy consumption of the project, which attempts to provide implications for the upgrading of energy-intensive seawater desalination in coastal areas towards low-carbon transition.


Assuntos
Água do Mar , Vento , Água do Mar/química , Purificação da Água/métodos , Salinidade
20.
Mar Pollut Bull ; 207: 116939, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39243471

RESUMO

Marine microorganisms like Tistrella are essential for producing bioactive compounds, including didemnins with antitumor and antiviral properties. However, our understanding of Tistrella's ecological features and didemnin production in natural environments is limited. In this study, we used genomics and metagenomics to show that Tistrella is widely distributed across natural habitats, especially in marine environments from the surface to 5000 m deep, with distinct non-random distribution patterns revealed by co-occurrence analysis. Importantly, transcriptional profiling of didemnin biosynthetic gene clusters indicates active in situ production of this compound within marine ecosystems. These findings enhance our understanding of Tistrella's ecology and secondary metabolite production in natural environments. Further research is needed to explore the ecological dynamics and functional impacts of Tistrella in these ecosystems.


Assuntos
Ecossistema , Microbiota , Organismos Aquáticos , Metagenômica , Água do Mar/microbiologia , Água do Mar/química
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