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1.
Artigo em Inglês | MEDLINE | ID: mdl-34085922

RESUMO

Two Gram-stain-negative and non-flagellated bacteria, YSTF-M3T and YSTF-M6T, were isolated from a tidal flat from Yellow Sea, Republic of Korea, and subjected to a polyphasic taxonomic study. Neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strains YSTF-M3T and YSTF-M6T belong to the genera Kordia and Olleya of the family Flavobacteriaceae, respectively. The 16S rRNA gene sequence similarities between strain YSTF-M3T and the type strains of Kordia species and between strain YSTF-M6T and the type strains of Olleya species were 94.1-98.4 and 97.3-98.3 %, respectively. The ANI and dDDH values between genomic sequences of strain YSTF-M3T and the type strains of five Kordia species and between those of strain YSTF-M6T and the type strains of three Olleya species were in ranges of 77.0-83.2 and 20.7-27.1 % and 79.4-81.5 and 22.3-23.9 %, respectively. The DNA G+C contents of strain YSTF-M3T and YSTF-M6T from genomic sequences were 34.1 and 31.1 %, respectively. Both strains contained MK-6 as predominant menaquinone and phosphatidylethanolamine as only major phospholipid identified. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strains YSTF-M3T and YSTF-M6T are separated from recognized species of the genera Kordia and Olleya, respectively. On the basis of the data presented, strains YSTF-M3T (=KACC 21639T=NBRC 114499T) and YSTF-M6T (=KACC 21640T=NBRC 114500T) are considered to represent novel species of the genera Kordia and Olleya, respectively, for which the names Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov. are proposed.


Assuntos
Flavobacteriaceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
2.
Nat Commun ; 12(1): 3325, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34083545

RESUMO

In contrast to its productive coastal margins, the open-ocean Gulf of Mexico (GoM) is notable for highly stratified surface waters with extremely low nutrient and chlorophyll concentrations. Field campaigns in 2017 and 2018 identified low rates of turbulent mixing, which combined with oligotrophic nutrient conditions, give very low estimates for diffusive flux of nitrate into the euphotic zone (< 1 µmol N m-2 d-1). Estimates of local N2-fixation are similarly low. In comparison, measured export rates of sinking particulate organic nitrogen (PON) from the euphotic zone are 2 - 3 orders of magnitude higher (i.e. 462 - 1144 µmol N m-2 d-1). We reconcile these disparate findings with regional scale dynamics inferred independently from remote-sensing products and a regional biogeochemical model and find that laterally-sourced organic matter is sufficient to support >90% of open-ocean nitrogen export in the GoM. Results show that lateral transport needs to be closely considered in studies of biogeochemical balances, particularly for basins enclosed by productive coasts.


Assuntos
Nitrogênio/análise , Água do Mar/química , Carbono/análise , Difusão , Golfo do México , Nitratos/análise , Fixação de Nitrogênio , Movimentos da Água
3.
J Environ Radioact ; 235-236: 106593, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34062380

RESUMO

Radionuclides produced by 20th-century human nuclear activities from 1945 (e.g., atmospheric nuclear explosions and nuclear-fuel reprocessing) made significant impacts on earth's surface environments. Long-lived shallow-water corals living in tropical/subtropical seas incorporate the anthropogenically-produced radionuclides, including 129I and 14C, into their skeletons, and provide time series records of the impacts of nuclear activities. Here, we present 129I/127I and Δ14C time series records of an annually-banded modern coral skeleton from Rowley Shoals, off the northwestern coast of Australia, in the far eastern Indian Ocean. The 129I/127I and Δ14C records, covering the period 1930s-1990s, exhibit distinct increases caused by the nuclear activities, and their increasing profiles are clearly different from each other. The first distinct 129I/127I increase occurs from 1955 to 1959, followed by a decrease in 1960-1963. The increase is probably due to US atmospheric nuclear explosions in Bikini and Eniwetok Atolls in 1954, 1956 and 1958. The 129I produced in those nuclear tests would be transported by the North Equatorial Current, a portion of which passes through the Indonesian Throughflow and then reaches Rowley Shoals. This initial increase from 1955 is, however, absent in the Δ14C record, which shows a distinct increase from 1959 and its peak around the mid-1970s, followed by a gradual decrease. This absence and the 4-year-delayed Δ14C increase are likely due to dilution of explosion-produced 14C with natural carbon (by seawater mixing and air-sea gas exchange) being much more intense than that of explosion-produced 129I with natural iodine (by the same processes), suggesting that the 129I/127I ratio is a more conservative anthropogenic tracer in surface ocean waters, as compared to Δ14C. The second 129I/127I increase is contemporaneous with a rapid Δ14C increase during 1964-1967, followed by a rapid 129I/127I decrease in 1968-1969; the increases can be ascribed to very large atmospheric nuclear explosions conducted in the former Soviet Union in 1961-1962. The third 129I/127I increase appears between 1969/1970 and 1992, which can be attributed to airborne 129I released from nuclear-fuel reprocessing facilities in Europe, the former Soviet Union and the US. The coral 129I/127I and Δ14C time series records, combined with previous studies, enhance our understanding of the behavior of anthropogenic 129I and 14C in the global ocean and atmosphere.


Assuntos
Antozoários , Monitoramento de Radiação , Animais , Atmosfera , Austrália , Europa (Continente) , Humanos , Oceano Índico , Indonésia , Radioisótopos do Iodo , Água do Mar , U.R.S.S.
4.
Wei Sheng Yan Jiu ; 50(3): 472-475, 2021 May.
Artigo em Chinês | MEDLINE | ID: mdl-34074371

RESUMO

OBJECTIVE: To understand the health status and influencing factors of people in bathing beach after bathing. METHODS: A questionnaire survey was conducted among the beach tourists in Hebei, Shandong and Shanghai Provinces from May to September, 2019-2020, including personal basic information, seawater/beach exposure in the last 7 days, beach activities, personal protective measures, physical health, related symptoms or diseases after bathing, etc. The seawater samples and sand of the three bathing beaches were sampled and detected. RESULTS: A total of 1222 valid questionnaires were collected. Skin infection(26. 19%), nasal congestion(12. 36%) and eye infection(8. 18%) were the most common symptoms of the tourist after seawater bath. Multivariate logistic regression analysis showed that previous physical discomfort(OR=0. 08-140. 73, 95%CI 0. 04-443. 64) was the common factor of all symptoms(P& lt; 0. 05), the risk factors of stomach cramps, eye infection, nasal congestion and sore throat were no wear of turbinate(OR=4. 65, 95% CI 1. 53-14. 08) and goggles(OR=541. 52, 95% CI 121. 58-2411. 85), swallowing seawater(OR=2. 29-79. 78, 95%CI 19. 83-296. 78) respectively(P& lt; 0. 05). CONCLUSION: Personal protective measures and physical conditions affect people& apos; s symptoms and diseases after bathing. There is microbial pollution in beach water and sand.


Assuntos
Praias , Microbiologia da Água , China/epidemiologia , Cidades , Monitoramento Ambiental , Humanos , Água do Mar , Água
5.
Artigo em Inglês | MEDLINE | ID: mdl-34003740

RESUMO

A Gram-stain negative, rod-shaped, facultatively aerobic, pale-beige-coloured bacterial strain, designated F7233T, was isolated from coastal sediment sampled at Jingzi Bay, Weihai, PR China. Cells of strain F7233T were 0.3-0.4 µm wide, 1.2-1.4 µm wide long, non-spore-forming and motile with one flagellum. Optimum growth occurred at 30 °C, with 1.0 % (w/v) NaCl and at pH 6.5-7.0. Positive for nitrate reduction, hydrolysis of Tweens and oxidase activity. The sole respiratory quinone of strain F7233T was ubiquinone-10 and the predominant cellular fatty acid was summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and one unidentified aminophospholipid. The G+C content of the chromosomal DNA was 63.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence revealed that the newly isolate belonged to the genus Stappia, with 96.8 % sequence similarity to Stappia indica MCCC 1A01226T, 96.1 % similarity to Stappia stellulata JCM 20692T and 95.5% similarity to Stappia taiwanensis CC-SPIO-10-1T. On the basis of phylogenetic, phenotypic and chemotaxonomic data, it is considered that strain F7233T should represent a novel species within the genus Stappia, for which the name Stappia albiluteola sp. nov. is proposed. The type strain is F7233T (=MCCC 1H00419T=KCTC 72859T).


Assuntos
Sedimentos Geológicos/microbiologia , Filogenia , Rhodobacteraceae/classificação , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
6.
Nat Commun ; 12(1): 3060, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34031385

RESUMO

The pelagic brown macroalgae Sargassum spp. have grown for centuries in oligotrophic waters of the North Atlantic Ocean supported by natural nutrient sources, such as excretions from associated fishes and invertebrates, upwelling, and N2 fixation. Using a unique historical baseline, we show that since the 1980s the tissue %N of Sargassum spp. has increased by 35%, while %P has decreased by 44%, resulting in a 111% increase in the N:P ratio (13:1 to 28:1) and increased P limitation. The highest %N and δ15N values occurred in coastal waters influenced by N-rich terrestrial runoff, while lower C:N and C:P ratios occurred in winter and spring during peak river discharges. These findings suggest that increased N availability is supporting blooms of Sargassum and turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health.


Assuntos
Nitrogênio/análise , Nutrientes , Sargassum/química , Água do Mar/química , Animais , Oceano Atlântico , Biomassa , Ecossistema , Peixes , Proliferação Nociva de Algas , Biologia Marinha , Rios , Sargassum/crescimento & desenvolvimento , Alga Marinha
7.
Nat Commun ; 12(1): 3037, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34031392

RESUMO

Microbialites accrete where environmental conditions and microbial metabolisms promote lithification, commonly through carbonate cementation. On Little Ambergris Cay, Turks and Caicos Islands, microbial mats occur widely in peritidal environments above ooid sand but do not become lithified or preserved. Sediment cores and porewater geochemistry indicated that aerobic respiration and sulfide oxidation inhibit lithification and dissolve calcium carbonate sand despite widespread aragonite precipitation from platform surface waters. Here, we report that in tidally pumped environments, microbial metabolisms can negate the effects of taphonomically-favorable seawater chemistry on carbonate mineral saturation and microbialite development.


Assuntos
Compostos de Cálcio/química , Ecossistema , Óxidos/química , Areia/química , Areia/microbiologia , Carbonato de Cálcio/metabolismo , Carbonatos , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Microbiota , Minerais , Água do Mar/química , Água do Mar/microbiologia , Índias Ocidentais
8.
Extremophiles ; 25(3): 235-248, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33938982

RESUMO

Picoeukaryotes constitute an important component of the living biomass of oceanic communities and play major roles in biogeochemical cycles. There are very few studies on picoeukaryotes found in the Chukchi Sea. This work shows the relationship between community distribution and composition of picoeukaryotes residing in water masses and physicochemical factors in the southern Chukchi Sea studied in both midsummer (July) and early autumn (September), 2012. Illumina 18S V4 rDNA metabarcoding were used as the main tool. In July, Mamiellophyceae, Dinophyceae, and Trebouxiophyceae were the main microbial classes, with Micromonas, Prasinoderma, Telonema, Amoebophrya, Bathycoccus, Picomonas, and Bolidomonas representing the main genera. In September, Trebouxiophyceae surpassed Dinophyceae and was the second main microbial class, with Micromonas, Prasinoderma, Bathycoccus, Bolidomonas, Telonema, Choricystis, and Diaphanoeca representing the main genera. Water mass was the primary factor determining the community composition and diversity of picoeukaryotes. Abundance of Bathycoccus was found to be highly correlated with Alaskan Coastal Water and that of Prasinoderma, Bolidomonas, and Diaphanoeca with Bering Seawater. Nitrate and phosphate content of water in midsummer and dissolved oxygen (DO) and temperature in early autumn were the main factors that shaped the abundance of the picoeukaryote community.


Assuntos
Clorófitas , Água do Mar , Clorófitas/genética , Sequenciamento de Nucleotídeos em Larga Escala , Oceanos e Mares , Estações do Ano
9.
Environ Monit Assess ; 193(6): 328, 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33956244

RESUMO

Petroleum contamination of marine environments due to exploitation and accidental spills causes serious harm to ecosystems. Bioremediation with immobilized microorganisms is an environmentally friendly and cost-effective emerging technology for treating oil-polluted environments. In this study, Bacillus licheniformis was entrapped in Ca alginate beads using the electrospray technique for light crude oil biodegradation. Three important process variables, including inoculum size (5-15% v/v), initial oil concentration (1500-3500 ppm), and NaCl concentration (0-30 g/L), were optimized to obtain the best response of crude oil removal using response surface methodology (RSM) and Box-Behnken design (BBD). The highest crude oil removal of 79.58% was obtained for 1500 ppm of crude oil after 14 days using immobilized cells, and it was lower for freely suspended cells (64.77%). Our result showed similar trends in the effect of variables on the oil biodegradation rate in both free cell (FC) and immobilized cell (IC) systems. However, according to the analysis of variance (ANOVA) results, the extent of the variables' effectiveness was different in FC and IC systems. In the immobilized cell system, all variables had a greater effect on the rate of light crude oil degradation. Moreover, to evaluate the effectiveness of free and immobilized B. licheniformis in bioremediation of an actual polluted site, the crude oil spill in natural seawater was investigated. The results suggested the stability of beads in the seawater, as well as high degradation of petroleum hydrocarbons by free and immobilized cells in the presence of indigenous microorganisms.


Assuntos
Bacillus licheniformis , Poluição por Petróleo , Petróleo , Alginatos , Biodegradação Ambiental , Ecossistema , Monitoramento Ambiental , Petróleo/análise , Poluição por Petróleo/análise , Água do Mar
10.
J Environ Manage ; 290: 112604, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33957411

RESUMO

In the face of increasing water shortages worldwide, water desalination has the potential to expand the available freshwater supply options in many water stressed regions. This paper assesses the feasibility of adopting photovoltaic powered small-scale brackish water desalination units in a coastal aquifer facing saltwater intrusion and chronic water shortages. Moreover, a detailed cost comparison, which incorporates the associated environmental costs, is conducted between the Electrodialysis Reversal (EDR) technique and Reverse Osmosis (RO). The results showed that PV-powered small-scale desalination units were more economically viable as compared to grid-powered units, when the electricity tariffs reflected non-subsidized electricity prices and environmental costs were internalized. EDR-PV proved to be more economically feasible and with a lower environmental footprint as compared to RO-PV, up until the salinity of the aquifer was below 5000 ppm (EDR: 0.57-1.18 $/m3; RO = 1.19-1.59 $/m3). Beyond that salinity, the RO-PV was found to be the more economically viable option, with costs reaching as high as 2.65 $/m3 at a salinity of 25,000 ppm. Overall, the environmental costs between the two technologies varied significantly, largely due to differences in the generated brine volume, with EDR having better efficiencies at lower salinity levels. Finally, the study highlighted the risk of accelerating saltwater intrusion as a result of the increased market penetration of solar-powered desalination units along vulnerable coastal aquifers.


Assuntos
Água Subterrânea , Purificação da Água , Estudos de Viabilidade , Osmose , Águas Salinas , Salinidade , Água do Mar
11.
Sci Total Environ ; 779: 146465, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34030232

RESUMO

Modern lifestyle demands high-end commodities, for instance, cosmetics, detergents, shampoos, household cleaning, sanitary items, medicines, and so forth. In recent years, these products' consumption has increased considerably, being antibiotics and some other pharmaceutical and personal care products (PPCPs). Several antibiotics and PPCPs represent a wide range of emerging contaminants with a straight ingress into aquatic systems, given their high persistence in seawater, effluent treatment plants, and even drinking water. Under these considerations, the necessity of developing new and affordable technologies for the treatment and sustainable mitigation of pollutants is highly requisite for a safer and cleaner environment. One possible mitigation solution is an effective deployment of nanotechnological cues as promising matrices that can contribute by attending issues and improving the current strategies to detect, prevent, and mitigate hazardous pollutants in water. Focused on nanoparticles' distinctive physical and chemical properties, such as high surface area, small size, and shape, metallic nanoparticles (MNPs) have been investigated for water remediation. MNPs gained increasing interest among research groups due to their superior efficiency, stability, and high catalyst activity compared with conventional systems. This review summarizes the occurrence of antibiotics and PPCPs and the application of MNPs as pollutant mitigators in the aquatic environment. The work also focuses on transportation fate, toxicity, and current regulations for environmental safety.


Assuntos
Cosméticos , Poluentes Ambientais , Preparações Farmacêuticas , Poluentes Químicos da Água , Cosméticos/análise , Monitoramento Ambiental , Compostos Orgânicos , Água do Mar , Águas Residuárias , Poluentes Químicos da Água/análise
12.
Ying Yong Sheng Tai Xue Bao ; 32(5): 1863-1872, 2021 May.
Artigo em Chinês | MEDLINE | ID: mdl-34042383

RESUMO

Microbial mineralization of organic phosphorus is an important component of marine phosphorus cycle. The research on organic phosphate-mineralizing bacteria (OPB) is helpful to reveal microbial driving mechanism of organic phosphorus mineralization in eutrophic sea area. The diversity and community characteristics of OPB were examined by Illumina high-throughput sequencing using the primer sets phoX in the sea area between Minjiang Estuary to Pingtan in April (spring) and July (summer) 2019. The results showed that the Shannon index of OPB in the surface seawater samples ranged from 3.21 to 7.91, and that the diversity at each station was greater in spring than that in summer. Shannon index of OPB in the sediment samples ranged from 2.04 to 8.70, which was greater in summer than that in spring. Shannon index of OPB in surface seawater of each station was higher than that of sediment in spring, while it was in adverse in summer. Nine phyla of OPB were detected in surface seawater, with Proteobacteria and Cyanobacteria being the most abundant. Tweleve phyla of OPB were detected in the sediments, with Proteobacteria and Bacteroidetes being the most dominant. OPB community composition at the genus level showed obvious spatio-temporal variation. Leisingera, Phaeobacter, Thalassococcus, and Pseudomonas were the major genera in the seawater in spring, while Synechococcus, Halioglobus, Roseovarius, Phaeo-bacter, Sulfitobacter, and Hyphomonas were the major genera detected in summer. Leisingera, Phaeobacter, Vibrio, and Sulfitobacter were major genera in the sediment in spring, while Azospirillum, Aminobacter, Sulfurifustis, Burkholderia, and Thiohalobacter were the major genera in summer. A large number of unclassified OPB were detected in both surface seawater and sediment. The redundancy analysis results showed that dissolved oxygen, water temperature, pH, dissolved inorganic nitrogen, NO2--N, and NO3--N had great influences on community distribution of OPB in the surface seawater. The abundant OPB in the surface seawater and sediment might play an important role in phosphorus cycle in this sea area.


Assuntos
Estuários , Sedimentos Geológicos , China , Organofosfatos , Fósforo/análise , Água do Mar
13.
Environ Monit Assess ; 193(6): 366, 2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34046759

RESUMO

A study was carried out in the coastal waters of Kalpakkam with the objectives to evaluate the seasonality in hydrobiological parameters in surface and bottom waters, and assess the anthropogenic stress and monsoonal flux on a spatiotemporal scale. The study covered an area of approximately 100 km2 in the coastal environment. Relatively high values for pH, temperature, and TP were observed during the post-monsoon (POM) season. The monsoon (MON) season was linked with TN, ammonia, and DO concentrations as all these parameters have shown increased values during this season due to freshwater input. The summer (SUM) season was characterized by salinity, turbidity, nitrate, phosphate, and silicate, indicating a true marine environmental condition for plankton production. Principal component analysis (PCA) and cluster analysis (CA) indicated the presence of distinct coastal water masses with respect to seasons and sampling regions. The spatial pattern indicated the distinctness of the coastal nearshore water (CNW) and coastal offshore water (COW) with respect to water quality. The CNW was more dynamic due to direct external influence as compared to the relatively stable COW environment. Similarly, the study region in the northern part, which is continuously exposed to the backwater inputs and tourism activities, was statistically different from the southern part.


Assuntos
Baías , Água do Mar , Monitoramento Ambiental , Índia , Estações do Ano
14.
Undersea Hyperb Med ; 48(2): 119-126, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33975402

RESUMO

Exposure to a reduction in ambient pressure such as in high-altitude climbing, flying in aircrafts, and decompression from underwater diving results in circulating vascular gas bubbles (i.e., venous gas emboli [VGE]). Incidence and severity of VGE, in part, can objectively quantify decompression stress and risk of decompression sickness (DCS) which is typically mitigated by adherence to decompression schedules. However, dives conducted at altitude challenge recommendations for decompression schedules which are limited to exposures of 10,000 feet in the U.S. Navy Diving Manual (Rev. 7). Therefore, in an ancillary analysis within a larger study, we assessed the evolution of VGE for two hours post-dive using echocardiography following simulated altitude dives at 12,000 feet. Ten divers completed two dives to 66 fsw (equivalent to 110 fsw at sea level by the Cross correction method) for 30 minutes in a hyperbaric chamber. All dives were completed following a 60-minute exposure at 12,000 feet. Following the dive, the chamber was decompressed back to altitude for two hours. Echocardiograph measurements were performed every 20 minutes post-dive. Bubbles were counted and graded using the Germonpré and Eftedal and Brubakk method, respectively. No diver presented with symptoms of DCS following the dive or two hours post-dive at altitude. Despite inter- and intra-diver variability of VGE grade following the dives, the majority (11/20 dives) presented a peak VGE Grade 0, three VGE Grade 1, one VGE Grade 2, four VGE Grade 3, and one VGE Grade 4. Using the Cross correction method for a 66-fsw dive at 12,000 feet of altitude resulted in a relatively low decompression stress and no cases of DCS.


Assuntos
Altitude , Mergulho/fisiologia , Embolia Aérea/diagnóstico por imagem , Adulto , Pressão Atmosférica , Exercícios Respiratórios , Descompressão/métodos , Descompressão/estatística & dados numéricos , Doença da Descompressão/etiologia , Doença da Descompressão/prevenção & controle , Ecocardiografia , Embolia Aérea/etiologia , Humanos , Masculino , Valores de Referência , Água do Mar , Treinamento por Simulação , Fatores de Tempo
15.
J Phys Chem Lett ; 12(20): 5023-5029, 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34024101

RESUMO

Lipopolysaccharides (LPS) in sea spray aerosol (SSA) particles have recently been shown to undergo heterogeneous reactions with HNO3 in the atmosphere. Here, we integrate theory and experiment to further investigate how the most abundant sea salt cations, Na+, Mg2+, and Ca2+, impact HNO3 reactions with LPS-containing SSA particles. Aerosol reaction flow tube studies show that heterogeneous reactions of SSA particles with divalent cation (Mg2+ and Ca2+) and LPS signatures were less reactive with HNO3 than those dominated by monovalent cations (Na+). All-atom molecular dynamics simulations of model LPS aggregates suggest that divalent cations cross-link the oligosaccharide chains to increase molecular aggregation and rigidity, which changes the particle phase and morphology, decreases water diffusion, and consequently decreases the reactive uptake of HNO3. This study provides new insight into how complex chemical interactions between ocean-derived salts and biogenic organic species can impact the heterogeneous reactivity of SSA particles.


Assuntos
Cálcio/química , Lipopolissacarídeos/química , Magnésio/química , Ácido Nítrico/química , Água do Mar/química , Sódio/química , Aerossóis/química , Cátions/química , Tamanho da Partícula , Sais/química , Propriedades de Superfície
16.
Nat Commun ; 12(1): 3235, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-34050175

RESUMO

Anaerobic oxidation of ammonium (anammox) in oxygen minimum zones (OMZs) is a major pathway of oceanic nitrogen loss. Ammonium released from sinking particles has been suggested to fuel this process. During cruises to the Peruvian OMZ in April-June 2017 we found that anammox rates are strongly correlated with the volume of small particles (128-512 µm), even though anammox bacteria were not directly associated with particles. This suggests that the relationship between anammox rates and particles is related to the ammonium released from particles by remineralization. To investigate this, ammonium release from particles was modelled and theoretical encounters of free-living anammox bacteria with ammonium in the particle boundary layer were calculated. These results indicated that small sinking particles could be responsible for ~75% of ammonium release in anoxic waters and that free-living anammox bacteria frequently encounter ammonium in the vicinity of smaller particles. This indicates a so far underestimated role of abundant, slow-sinking small particles in controlling oceanic nutrient budgets, and furthermore implies that observations of the volume of small particles could be used to estimate N-loss across large areas.


Assuntos
Compostos de Amônio/metabolismo , Bactérias/metabolismo , Ciclo do Nitrogênio , Nitrogênio/metabolismo , Anaerobiose , Oceanos e Mares , Oxirredução , Peru , Água do Mar/química , Água do Mar/microbiologia
17.
Proc Biol Sci ; 288(1950): 20210130, 2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-33975470

RESUMO

The future of coral reef ecosystems is under threat because vital reef-accreting species such as coralline algae are highly susceptible to ocean acidification. Although ocean acidification is known to reduce coralline algal growth rates, its direct effects on the development of coralline algal reproductive structures (conceptacles) is largely unknown. Furthermore, the long-term, multi-generational response of coralline algae to ocean acidification is extremely understudied. Here, we investigate how mean pH, pH variability and the pH regime experienced in their natural habitat affect coralline algal conceptacle abundance and size across six generations of exposure. We show that second-generation coralline algae exposed to ocean acidification treatments had conceptacle abundances 60% lower than those kept in present-day conditions, suggesting that conceptacle development is initially highly sensitive to ocean acidification. However, this negative effect of ocean acidification on conceptacle abundance disappears after three generations of exposure. Moreover, we show that this transgenerational acclimation of conceptacle development is not facilitated by a trade-off with reduced investment in growth, as higher conceptacle abundances are associated with crusts with faster growth rates. These results indicate that the potential reproductive output of coralline algae may be sustained under future ocean acidification.


Assuntos
Rodófitas , Água do Mar , Aclimatação , Recifes de Corais , Ecossistema , Concentração de Íons de Hidrogênio , Oceanos e Mares
18.
Mar Pollut Bull ; 167: 112364, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33933897

RESUMO

This article provides an overview of the impacts of climate change stressors (temperature, ocean acidification, sea-level rise, and hypoxia) on estuarine and marine biota (algae, crustaceans, molluscs, corals, and fish). It also assessed possible/likely interactive impacts (combined impacts of climate change stressors and pollutants) on pollutants mobilization, pollutants toxicity (effects on growth, reproduction, mortality) and pollutants bioaccumulation in estuarine and marine biota. An increase in temperature and extreme events may enhance the release, degradation, transportation, and mobilization of both hydrophobic and hydrophilic pollutants in the estuarine and marine environments. Based on the available pollutants' toxicity trend data and information it reveals that the toxicity of several high-risk pollutants may increase with increasing levels of climate change stressors. It is likely that the interactive effects of climate change and pollutants may enhance the bioaccumulation of pollutants in seafood organisms. There is a paucity of literature relating to realistic interactive effects of climate change and pollutants. Therefore, future research should be directed towards the combined effects of climate change stressors and pollutants on estuarine and marine bota. A sustainable solution for pollution control caused by both greenhouse gas emissions (that cause climate change) and chemical pollutants would be required to safeguard the estuarine and marine biota.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Animais , Bioacumulação , Biota , Mudança Climática , Concentração de Íons de Hidrogênio , Alimentos Marinhos , Água do Mar
19.
Nat Commun ; 12(1): 2556, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33963184

RESUMO

Ensuring that global warming remains <2 °C requires rapid CO2 emissions reduction. Additionally, 100-900 gigatons CO2 must be removed from the atmosphere by 2100 using a portfolio of CO2 removal (CDR) methods. Ocean afforestation, CDR through basin-scale seaweed farming in the open ocean, is seen as a key component of the marine portfolio. Here, we analyse the CDR potential of recent re-occurring trans-basin belts of the floating seaweed Sargassum in the (sub)tropical North Atlantic as a natural analogue for ocean afforestation. We show that two biogeochemical feedbacks, nutrient reallocation and calcification by encrusting marine life, reduce the CDR efficacy of Sargassum by 20-100%. Atmospheric CO2 influx into the surface seawater, after CO2-fixation by Sargassum, takes 2.5-18 times longer than the CO2-deficient seawater remains in contact with the atmosphere, potentially hindering CDR verification. Furthermore, we estimate that increased ocean albedo, due to floating Sargassum, could influence climate radiative forcing more than Sargassum-CDR. Our analysis shows that multifaceted Earth-system feedbacks determine the efficacy of ocean afforestation.


Assuntos
Atmosfera/análise , Dióxido de Carbono/análise , Aquecimento Global/prevenção & controle , Sargassum/isolamento & purificação , Oceano Atlântico , Biomassa , Cálcio/análise , Ecossistema , Retroalimentação , Concentração de Íons de Hidrogênio , Água do Mar/análise , Água do Mar/química , Temperatura , Fatores de Tempo , Clima Tropical
20.
Sci Total Environ ; 786: 147470, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-33975101

RESUMO

"Candidatus Scalindua", as known as marine anammox bacteria (MAB), was engineered to remove nitrogen from seawater-based wastewater (SWW). In this study, "Candidatus Scalindua" was successfully enriched within 106 days with marine sediments as inoculated sludge. The operating temperature was 20 ± 2 °C, and influent pH was 7.5 ± 0.1. Ammonia (NH4+-N) removal rate (ARR) was 0.53 kg/(m3·d) with the NH4+-N loading rate of 0.68 kg/(m3·d), and nitrite (NO2--N) removal rate (NRR) was 0.57 kg/(m3·d) at 0.89 kg/(m3·d) NO2--N loading rate. Nitrogen removal was negatively affected at an influent NO2- above 224 mg/L, which decreased the ARR and NRR to 0.36 and 0.31 kg/(m3·d), respectively. The genus "Ca. Scalindua" dominated the reactor, and it synergistically coexisted with Marinicella to achieve efficient nitrogen removal. This work would help to better understand the nitrogen removal properties and microbial characterization of MAB in SWW wastewater treatment under low temperature.


Assuntos
Nitrogênio , Águas Residuárias , Anaerobiose , Bactérias , Reatores Biológicos , Desnitrificação , Oxirredução , Água do Mar
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