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1.
Environ Monit Assess ; 192(11): 694, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-33037931

RESUMO

Evaporation, as the main source of water loss from closed lakes, makes a significant contribution to the water balance equation of the lake and can lead to changes in the chemical composition thereof. The objective of the study was to develop an equation for estimation of evaporation from the water surface with different depths and concentrations. To that end, 48 barrels were used to model evaporation at 6 different depths and 8 different concentrations of salinity. The experiments have been conducted in the same meteorological condition for all the barrels near the Urmia Lake. Data were collected in March 1, 2019, to Aug 31, 2019. Different equations fitted to data for each concentrations of salinity separately with different depths, and the equations with the least errors were selected. A model was then developed for the estimation of evaporation, considering the effect of salinity and depth, and the results were compared with daily measurements. The results were evaluated using the root mean square error (RMSE), correlation coefficient (CC), and Nash-Sutcliffe efficiency coefficient (NS). The results indicated that evaporation (Horizontal row) from water surface with high concentrations of salinity to low concentrations of salinity in different depths had an incremental trend. However, it can be seen in the vertical row that evaporation increased from low depth to high depth, and then decreased at a certain depth (120 cm) while the maximum evaporation rate belonged to 90-cm barrels for each concentration of salinity (in the vertical and horizontal row). At the end, the comparison of evaporation computed from the model and measured data showed that the model estimated evaporation at different depths and concentrations of salinity satisfactorily.


Assuntos
Monitoramento Ambiental , Meteorologia , Lagos , Águas Salinas , Salinidade
2.
Mar Environ Res ; 160: 105014, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907732

RESUMO

Alexandrium minutum and Alexandrium pacificum are representatives of the dinoflagellate genus that regularly proliferate on the French coasts and other global coastlines. These harmful species may threaten shellfish harvest and human health due to their ability to synthesize neurotoxic alkaloids of the saxitoxin group. However, some dinoflagellates such as A. minutum, and as reported here A. pacificum as well, may also have a beneficial impact on the environment by producing dimethylsulfoniopropionate-DMSP, the precursor of dimethylsulfur-DMS and sulfate aerosols involved in climate balance. However, environmental conditions might influence Alexandrium physiology towards the production of harmful or environmentally friendly compounds. After assessing the influence of two salinity regimes (33 and 38) relative to each species origin (Atlantic French coast and Mediterranean Lagoon respectively), it appears that DMSP and toxin content was variable between the three experimented strains and that higher salinity disadvantages toxin production and tends to favor the production of the osmolytes DMSP and glycine betaine. Hence, this key metabolite production is strain and species-dependent and is influenced by environmental conditions of salinity which in turn, can diversely affect the environment. Widespread coastal blooms of A. minutum and A. pacificum, although being a risk for seafood contamination with toxins, are also a DMSP and DMS source that potentially contribute to the ecosystem structuration and climate. Regarding recent advances in DMSP biosynthesis pathway, 3 dsyB homologs were found in A. minutum but no homolog of the diatom sequence TpMMT.


Assuntos
Diatomáceas , Dinoflagelados , Ecossistema , Proliferação Nociva de Algas , Humanos , Dinâmica Populacional , Salinidade , Frutos do Mar
3.
Environ Monit Assess ; 192(10): 641, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32929589

RESUMO

Monitoring the groundwater quality situation and identifying the various pollution loads' sources are a prerequisites to finding solutions. In many areas, nitrate and salinity are one of the prime pollutants in the groundwater. This investigation is carried to present the results of a monitoring study focusing on 20 wells samples collected from the shallow groundwater of Guenniche plain (North Tunisia) during the wet season of May 2016, to present its suitability for drinking purposes with emphasis on the assessment of the presence of nitrate and salinity elements. Nitrate levels' results show that 55% of the samples exceeded the National Tunisian standard limit (NT) and the World Health Organization standard limit (WHO). The salinity results, measured as total dissolved solids (TDS), show that 95% of the samples exceed the international standard, and 25% exceed the national standard. A total of 20% of the wells exceeded the nitrite standards. The total hardness levels indicate that 90% of the samples present very hard water. The Guenniche shallow groundwater average concentrations are categorized as follows: Na+ > Ca2+ > Mg2+ > K+ for the cations and Cl- > SO42- > HCO3- > NO3- for the anions. Nitrate and salinity variations during the period 2006-2015 follow the rainfall fluctuation patterns. The assessment of water quality using Water Quality Index revealed that 95% of the wells' water classes ranged between "poor", "very poor," and "unsuitable for drinking purposes". Therefore, these wells are affected by anthropogenic and/or natural factors and they are inadvisable for drinking purposes, unless the water from these wells undergoes appropriate treatment before use.


Assuntos
Água Potável , Água Subterrânea , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Salinidade , Tunísia , Qualidade da Água
4.
J Environ Manage ; 271: 111023, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778304

RESUMO

The utilization of swine wastewater is affected by salinity and pH owing to the extensive use with seawater instead of domestic water as swine farm flushing water in coastal city. Therefore, swine wastewater pretreated with thermophilic bacteria was used as fermentation substrate in this work, the effects of salinity and pH on dark fermentation under mesophilic condition were investigated. The research showed that 1.5% salinity and pH 6.0 were the optimal conditions for hydrogen production with swine wastewater. The activity of hydrogenogen was inhibited at 3.5% salinity and pH 5.0. Soluble organic matter in substrate was accumulated under high salinity and alkaline conditions. The utilization of carbohydrate during dark fermentation was up to 61.1% at 1.5% salinity and 51.5% at pH 9.0. Enhancing of salinity and pH had an advantage in accumulation of total soluble metabolites. Acetate was the main metabolite during dark fermentation, and 1.5% salinity contributed to the formation of butyrate.


Assuntos
Salinidade , Águas Residuárias , Animais , Bactérias , Reatores Biológicos , Fermentação , Hidrogênio , Concentração de Íons de Hidrogênio , Suínos
5.
Environ Pollut ; 265(Pt B): 115087, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806465

RESUMO

Removal of Hg(II) by biochar (BC) is a promising remediation technology. The high-salinity Spirulina residue (HSR) is a hazardous waste generated during extracting the pigment phycocyanin under high salinity conditions. Although HSR-derived BC (HSRBC) exhibited the excellent sorption capacity of Hg(II), the involved mechanisms have been rarely studied. In this study, we investigated the specific properties and Hg(II) sorption mechanisms of HSRBCs. Chloride and calcium minerals were formed in HSRBCs. Increments in carbonization temperature (from 350 to 700 °C) or time (from 90 to 540 min) led to the enhancement of aromaticity, porosity, and positive charge, but cracked oxygen-containing groups and C-N bonds. Further increase in carbonization temperature or time decreased the sorption of Hg(II). At environmentally relevant concentration of Hg(II) (2-4 mg/L), the sorption capacity (6.1-12.7 mg/g) obtained in HSRBC350 was comparable to activated carbon. Based on dual-mode isotherm, surface sorption accounted for 75-88% uptake, while precipitation accounted for 12-25% uptake. In addition, the C-O, CO, and CC groups were responsible for the monodentate/bidentate complexation and reduction, while Cl- triggered Hg2Cl2 precipitation. Overall, this study provided a new insight in creating an excellent Hg(II) sorbent from hazardous waste, and revealed the sorption mechanisms for Hg(II) uptake.


Assuntos
Mercúrio , Spirulina , Animais , Carvão Vegetal , Salinidade
6.
Environ Monit Assess ; 192(9): 604, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32857216

RESUMO

Soil quality is the competence of soil to perform necessary functions that are able to maintain animal and plant productivity of the soil. Soil consists of various physical, chemical, and biological parameters, and all these parameters are involved in the critical functioning of soil. There is a need for continuous assessment of soil quality as soil is a complex and dynamic constituent of Earth's biosphere that is continuously changing by natural and anthropogenic disturbances. Any perturbations in the soil cause disturbances in the physical (soil texture, bulk density, etc.), chemical (pH, salinity, organic carbon, etc.), and biological (microbes and enzymes) parameters. These physical, chemical, and biological parameters can serve as indicators for soil quality assessment. However, soil quality assessment cannot be possible by evaluating only one parameter out of physical, chemical, or biological. So, there is an emergent need to establish a minimum dataset (MDS) which shall include physical, chemical, and biological parameters to assess the quality of the given soil. This review attempts to describe various physical, chemical, and biological parameters, combinations of which can be used in the establishment of MDS.


Assuntos
Monitoramento Ambiental , Solo , Animais , Carbono/análise , Plantas , Salinidade
7.
Extremophiles ; 24(5): 773-785, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32749548

RESUMO

Haloarchaea have evolved to thrive in hypersaline environments. Haloferax volcanii is of particular interest due to its genetic tractability; however, few in vivo reporters exist for halophiles. Haloarchaeal proteins evolved characteristics that promote proper folding and function at high salt concentrations, but many mesophilic reporter proteins lack these characteristics. Mesophilic proteins that acquire salt-stabilizing mutations, however, can lead to proper function in haloarchaea. Using laboratory-directed evolution, we developed and demonstrated an in vivo luciferase that functions in the hypersaline cytosol of H. volcanii.


Assuntos
Haloferax volcanii , Proteínas Luminescentes , Salinidade , Genes Reporter , Haloferax volcanii/metabolismo , Proteínas Luminescentes/metabolismo
8.
PLoS Negl Trop Dis ; 14(8): e0008406, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776919

RESUMO

We hypothesized that Cholera (Vibrio cholerae) that appeared along Lake Kivu in the African Rift in the seventies, might be controlled by volcano-tectonic activity, which, by increasing surface water and groundwater salinity and temperature, may partly rule the water characteristics of Lake Kivu and promote V. cholerae proliferation. Volcanic activity (assessed weekly by the SO2 flux of Nyiragongo volcano plume over the 2007-2012 period) is highly positively correlated with the water conductivity, salinity and temperature of the Kivu lake. Over the 2007-2012 period, these three parameters were highly positively correlated with the temporal dynamics of cholera cases in the Katana health zone that border the lake. Meteorological variables (air temperature and rainfall), and the other water characteristics (namely pH and dissolved oxygen concentration in lake water) were unrelated to cholera dynamics over the same period. Over the 2016-2018 period, we sampled weekly lake water salinity and conductivity, and twice a month vibrio occurrence in lake water and fish. The abundance of V. cholerae in the lake was positively correlated with lake salinity, temperature, and the number of cholera cases in the population of the Katana health zone. V. cholerae abundance in fishes was positively correlated with V. cholerae abundance in lake water, suggesting that their consumption directly contaminate humans. The activity of the volcano, by controlling the physico-chemical characteristics of Lake Kivu, is therefore a major determinant of the presence of the bacillus in the lake. SO2 fluxes in the volcano plume can be used as a tool to predict epidemic risks.


Assuntos
Cólera/epidemiologia , Lagos/química , Lagos/microbiologia , Erupções Vulcânicas/efeitos adversos , Animais , República Democrática do Congo/epidemiologia , Condutividade Elétrica , Peixes/microbiologia , Humanos , Concentração de Íons de Hidrogênio , Oxigênio/análise , Ruanda , Salinidade , Dióxido de Enxofre/análise , Temperatura , Vibrio , Microbiologia da Água
9.
Environ Pollut ; 266(Pt 1): 115374, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32841840

RESUMO

Potentially toxic elements (PTEs) are of major concern due to their high persistence and toxicity. Recently, rare earth elements (REEs) concentration in aquatic ecosystems has been increasing due to their application in modern technologies. Thus, this work aimed to study, for the first time, the influence of REEs (lanthanum, cerium, praseodymium, neodymium, europium, gadolinium, terbium, dysprosium and yttrium) and of salinity (10 and 30) on the removal of PTEs (Cd, Cr, Cu, Hg, Ni and Pb) from contaminated waters by living macroalgae (Fucus spiralis, Fucus vesiculosus, Gracilaria sp., Osmundea pinnatifida, Ulva intestinalis and Ulva lactuca). Experiments ran for 168 h, with each macroalga exposed to saline water spiked with the six PTEs and with the six PTEs plus nine REEs (all at 1 µmol L-1) at both salinities. Results showed that all species have high affinity with Hg (90-99% of removal), not being affected neither by salinity changes nor by the presence of other PTEs or REEs. Cd showed the lowest affinity to most macroalgae, with residual concentrations in water varying between 50 and 108 µg L-1, while Pb removal always increased with salinity decline (up to 80% at salinity 10). REEs influence was clearer at salinity 30, and mainly for Pb. No substantial changes were observed in Ni and Hg sorption. For the remaining elements, the effect of REEs varied among algae species. Overall, the results highlight the role of marine macroalgae as living biofilters (particularly U. lactuca), capable of lowering the levels of top priority hazardous substances (particularly Hg) and other PTEs in water, even in the presence of the new emerging contaminants - REEs. Differences in removal efficiency between elements and macroalgae are explained by the contaminant chemistry in water and by macroalgae characteristics.


Assuntos
Mercúrio , Alga Marinha , Poluentes Químicos da Água/análise , Cádmio , Ecossistema , Chumbo , Salinidade
10.
Mar Pollut Bull ; 158: 111404, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753189

RESUMO

Coastal ecosystems, and especially estuaries, are subject to environmental fluctuations that can be amplified by anthropogenic changes. Under a future scenario of global warming, temperature and salinity are likely to be altered and the persistence of macrophyte-dominated ecosystems can be compromised, particularly native or local seagrass communities. This study examined the response of the local seagrass Halophila ovalis to the joint effect of a short-term salinity increase and a transient temperature stress, through two mesocosm experiments. Warming caused a decline in Fv/Fm, TNC content in leaves and plant growth, and increased dark respiration, revealing clear detrimental symptoms of heat stress on plant metabolism and performance. Salinity increase in isolation favoured ramet survival. However, in combination with warming, salinity had a positive effect on Gross Pmax. This suggests that increased salinities might dampen the negative effects of high temperatures, buffering, to some extent, the impact of global warming in temperate estuaries.


Assuntos
Hydrocharitaceae , Salinidade , Ecossistema , Aquecimento Global , Folhas de Planta
11.
Environ Monit Assess ; 192(9): 562, 2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32754777

RESUMO

The Digha-Shankarpur area in West Bengal suffers from the problem of saline water intrusion in the near-surface to shallow subsurface aquifers. In the present study, geophysical surveys were conducted and integrated with measured hydrogeological parameters to delineate the possible locations of saline water-invaded zones in the shallow aquifers. One hundred eighty-eight groundwater samples were collected, and parameters like salinity, EC, total dissolved solids (TDS), pH, temperature, and water level were measured. The geophysical survey, such as resistivity profiling, self-potential, and electrical resistivity imaging techniques, was applied. High TDS, salinity, and EC were observed in various places. Resistivity profiling survey indicates a low resistivity zone (< 10 Ωm), self-potential anomaly indicates a positive anomaly and resistivity imaging survey indicated very low resistivity zones (0-3 Ωm) in near-surface to shallow subsurface locations which are concurrent with the other coastal aquifers in the eastern part of India. These low resistivity zones are interpreted as saline water intrusion zone mixed with clay/sand layers up to a depth of 15 m possibly due to the ingression of seawater and also due to anthropogenic activities. Hence, protection from seawater intrusion from the canals into the coastal aquifers (shallow and deep) and human-made activities should be restricted to minimize the effect of saline water pollution.


Assuntos
Argila , Água Subterrânea , Monitoramento Ambiental , Índia , Salinidade , Areia , Água do Mar
12.
PLoS One ; 15(8): e0236129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760076

RESUMO

Salix matsudana, a member of Salicaceae, is an important ornamental tree in China. Because of its capability to tolerate high salt conditions, S. matsudana also plays an important ecological role when grown along Chinese coastal beaches, where the salinity content is high. Here, we aimed to elucidate the mechanism of higher salt tolerance in S. matsudana variety '9901' by identifying the associated genes through RNA sequencing and comparing differential gene expression between the S. matsudana salt-tolerant and salt-sensitive samples treated with 150 mM NaCl. Transcriptomic comparison of the roots of the two samples revealed 2174 and 3159 genes responsive to salt stress in salt-sensitive and salt-tolerant sample, respectively. Real-time polymerase chain reaction analysis of 9 of the responsive genes revealed a strong, positive correlation with RNA sequencing data. The genes were enriched in several pathways, including carbon metabolism pathway, plant-pathogen interaction pathway, and plant hormone signal transduction pathway. Differentially expressed genes (DEGs) encoding transcription factors associated with abiotic stress responses and salt stress response network were identified; their expression levels differed between the two samples in response to salt stress. Hub genes were also revealed by weighted gene co-expression network (WGCNA) analysis. For functional analysis of the DEG encoding sedoheptulose-1,7-bisphosphatase (SBPase), the gene was overexpressed in transgenic Arabidopsis, resulting in increased photosynthetic rates, sucrose and starch accumulation, and enhanced salt tolerance. Further functional characterization of other hub DEGs will reveal the molecular mechanism of salt tolerance in S. matsudana and allow the application of S. matsudana in coastal afforestation.


Assuntos
Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes/fisiologia , Salix/fisiologia , Tolerância ao Sal/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Fotossíntese/genética , Raízes de Plantas , Plantas Geneticamente Modificadas , RNA-Seq , Salinidade , Amido/metabolismo , Sacarose/metabolismo
13.
PLoS One ; 15(8): e0237730, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857799

RESUMO

Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (δ13CDOC, δ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota.


Assuntos
Ciclo do Carbono , Isótopos de Carbono/análise , Monitoramento Ambiental/métodos , Água Subterrânea/química , Microbiota/fisiologia , Solo/química , Austrália , Isótopos de Carbono/metabolismo , Código de Barras de DNA Taxonômico , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Água Subterrânea/microbiologia , RNA Ribossômico 16S/genética , Chuva , Salinidade , Microbiologia do Solo , Espectrometria de Fluorescência
14.
Ecotoxicol Environ Saf ; 204: 111073, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32755736

RESUMO

The high pH and salinity of textile wastewater is a major hindrance to azo dye decolorization. In this study, a mixed bacterial consortium ZW1 was enriched under saline (10% salinity) and alkaline (pH 10.0) conditions to decolorize Methanil Yellow G (MY-G). Consortium ZW1 was mainly composed of Halomonas (49.8%), Marinobacter (30.7%) and Clostridiisalibacter (19.2%). The effects of physicochemical factors were systematically investigated, along with the degradation pathway and metagenome analysis. The co-carbon source was found to be necessary, and the addition of yeast extract led to 93.3% decolorization of 100 mg/L MY-G within 16 h (compared with 1.12% for control). The optimum pH, salinity, temperature and initial dye concentration were 8.0, 5-10%, 40 °C and 100 mg/L, respectively. The typical dye-related degradation enzymes were most effective at 10% salinity. Consortium ZW1 was also able to differentially decolorize five other direct and acidic dyes in a short period. Phototoxicity tests revealed the detoxification of MY-G degradation products. Combining UV-vis, FTIR and GC-MS detection, the MY-G degradation pathway by consortium ZW1 was proposed. Furthermore, metagenomic approach was used to elucidate the functional potential of genes in MY-G biodegradation. These results signify the broad potential application of halo-alkaliphilic consortia in the bioremediation of dyeing wastewater.


Assuntos
Compostos Azo/toxicidade , Corantes/toxicidade , Metagenoma , Microbiota/efeitos dos fármacos , Águas Residuárias , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Compostos Azo/metabolismo , Biodegradação Ambiental , Carbono/metabolismo , Corantes/metabolismo , Microbiota/genética , Salinidade , Temperatura , Indústria Têxtil , Águas Residuárias/química , Águas Residuárias/microbiologia , Poluentes Químicos da Água/metabolismo
15.
J Water Health ; 18(4): 602-612, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32833686

RESUMO

Sand dams can be an effective community-scale solution to increasing water supplies in some arid and semi-arid regions, but there are few studies that have investigated water quality at sand dams. This study investigated the levels of coliform bacteria and salt content as parameters of potential concern. Most water taken from sand dam sources had fecal coliforms present. Median fecal coliforms were in the range of 150-800 cfu/100 ml for unprotected sources (scoop holes, surface water or hand dug wells), levels which are considered high or very high health risk. Pump wells had less contamination, with fecal coliforms detected in one-third of samples in the dry season. Despite this contamination, user surveys indicated that 74% of communities generally view water as clean for drinking, and 72% reported that no or few people in their community treat their water. Salt content in the dry season was in the poor or unacceptable range (above 900 ppm as total dissolved solids) in 33% of water samples. Results suggest that fecal coliforms and salt content represent two types of challenges to water quality at sand dams: fecal coliforms are a health hazard, whereas high salt content potentially reduces the amount of usable water that is available.


Assuntos
Água Potável/microbiologia , Salinidade , Microbiologia da Água , Abastecimento de Água/estatística & dados numéricos , Bactérias , Água Potável/química , Fezes , Quênia , Areia
16.
PLoS One ; 15(8): e0234892, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817668

RESUMO

The mosquito Aedes aegypti vectors the arboviral diseases yellow fever, dengue, Zika and chikungunya. Larvae are usually found developing in freshwater; however, more recently they have been increasingly found in brackish water, potential habitats which are traditionally ignored by mosquito control programs. Aedes aegypti larvae are osmo-regulators maintaining their hemolymph osmolarity in a range of ~ 250 to 300 mOsmol l-1. In freshwater, the larvae must excrete excess water while conserving ions while in brackish water, they must alleviate an accumulation of salts. The compensatory physiological mechanisms must involve the transport of ions and water but little is known about the water transport mechanisms in the osmoregulatory organs of these larvae. Water traverses cellular membranes predominantly through transmembrane proteins named aquaporins (AQPs) and Aedes aegypti possesses 6 AQP homologues (AaAQP1 to 6). The objective of this study was to determine if larvae that develop in freshwater or brackish water have differential aquaporin expression in osmoregulatory organs, which could inform us about the relative importance and function of aquaporins to mosquito survival under these different osmotic conditions. We found that AaAQP transcript abundance was similar in organs of freshwater and brackish water mosquito larvae. Furthermore, in the Malpighian tubules and hindgut AaAQP protein abundance was unaffected by the rearing conditions, but in the gastric caeca the protein level of one aquaporin, AaAQP1 was elevated in brackish water. We found that AaAQP1 was expressed apically while AaAQP4 and AaAQP5 were found to be apical and/or basal in the epithelia of osmoregulatory organs. Overall, the results suggest that aquaporin expression in the osmoregulatory organs is mostly consistent between larvae that are developing in freshwater and brackish water. This suggests that aquaporins may not have major roles in adapting to longterm survival in brackish water or that aquaporin function may be regulated by other mechanisms like post-translational modifications.


Assuntos
Aedes/genética , Aquaporinas/genética , Osmorregulação/genética , Aedes/fisiologia , Animais , Aquaporinas/metabolismo , Infecções por Arbovirus , Transporte Biológico , Ecossistema , Água Doce , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Hemolinfa/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Osmorregulação/fisiologia , Osmose , Águas Salinas , Salinidade , Água/metabolismo
17.
Ecol Lett ; 23(9): 1391-1403, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32627356

RESUMO

Understanding how stressors combine to affect population abundances and trajectories is a fundamental ecological problem with increasingly important implications worldwide. Generalisations about interactions among stressors are challenging due to different categorisation methods and how stressors vary across species and systems. Here, we propose using a newly introduced framework to analyse data from the last 25 years on ecological stressor interactions, for example combined effects of temperature, salinity and nutrients on population survival and growth. We contrast our results with the most commonly used existing method - analysis of variance (ANOVA) - and show that ANOVA assumptions are often violated and have inherent limitations for detecting interactions. Moreover, we argue that rescaling - examining relative rather than absolute responses - is critical for ensuring that any interaction measure is independent of the strength of single-stressor effects. In contrast, non-rescaled measures - like ANOVA - find fewer interactions when single-stressor effects are weak. After re-examining 840 two-stressor combinations, we conclude that antagonism and additivity are the most frequent interaction types, in strong contrast to previous reports that synergy dominates yet supportive of more recent studies that find more antagonism. Consequently, measuring and re-assessing the frequency of stressor interaction types is imperative for a better understanding of how stressors affect populations.


Assuntos
Salinidade , Temperatura
18.
Bioresour Technol ; 315: 123833, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32683286

RESUMO

In this study, the cross-talk between gama-aminobutyric acid (GABA) and calcium ion (Ca2+) signalling in the regulation of lipid production and cell growth in microalgae under fulvic acid and salinity stress (FA-salinity treatment) was investigated. GABA enhanced the lipid content and lipid productivity rate considerably, which were 1.27 and 1.29 times higher than those of the control, respectively. The levels of biosynthetic gene transcription, GSH, Ca2+ and cellular GABA were promoted by GABA addition, but decreased the ROS levels. Furthermore, the application of Ca2+ also increased lipid synthesis by regulating ROS and GABA signalling and lipogenesis-related genes. These results indicated that cytosolic GABA and Ca2+ levels exert crucial cross-talk in the modulation of cell growth and lipid accumulation induced by FA-salinity treatment. Collectively, this study demonstrated the beneficial effects caused by induction of the combination of chemical compounds on lipid production and provided new insights into lipid synthesis in microalgae.


Assuntos
Cálcio , Microalgas , Aminobutiratos , Benzopiranos , Lipídeos , Lipogênese , Salinidade , Estresse Salino
19.
Bioresour Technol ; 314: 123715, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32645570

RESUMO

This study proposed a novel approach of cultivating aerobic granular sludge (AGS) using intertidal wetland sediment (IWS) as inoculant in MBR for saline wastewater treatment. Granulation was observed in IWS-MBR during start-up, with increased sludge particle size (3.1-3.3 mm) and improved settling property (23.8 ml/g). The abundant inorganic particulates (acted as nuclei) and distinctive microbial community in IWS contributed to the granules formation. With the help of AGS, IWS-MBR system exhibited excellent TOC reduction of 90.3 ± 6.1% and significant TN reduction of 31.2 ± 5.0%, while the control MBR (Co-MBR) only showed 58.9 ± 7.2% and 10.4 ± 2.7%, respectively. Meanwhile, membrane fouling was mitigated in IWS-MBR, with a longer filtration cycle of 21.5 d, as compared with that of 8.9 d for Co-MBR. Microbial community analysis revealed that abundant functional bacteria associated with granulation and pollutants removal were enriched from IWS and set the basis for AGS formation and the superior treatment performance.


Assuntos
Esgotos , Águas Residuárias , Antibacterianos , Reatores Biológicos , Membranas Artificiais , Salinidade , Eliminação de Resíduos Líquidos , Áreas Alagadas
20.
Sci Total Environ ; 742: 140456, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629251

RESUMO

Complete ammonia-oxidizing (comammox) microorganisms are newly recognized nitrifying bacteria found in natural and engineered ecosystems. Mangrove ecosystems are hotspots for nitrogen cycling, but the knowledge of comammox diversity and abundance, and particularly, driving factors, in these ecosystems is scarce. We here used deep sequencing to investigate comammox diversity in six mangrove ecosystems across southeastern China. Our results showed that comammox microorganisms in mangrove sediments were extremely diverse. Phylogenetic analysis revealed a novel comammox group within clade A that formed a distinct cluster for which no reference sequence existed, implying their potential uniqueness. Quantitative PCR demonstrated that comammox abundance was slightly higher than that of the canonical ammonia-oxidizing bacteria but significantly lower than that of ammonia-oxidizing archaea, indicating they are not the dominant ammonia oxidizers in mangrove ecosystems. Finally, variation partition analysis revealed a significant decrease in similarity of comammox communities along the geographical distance, and a pronounced effect of the geographic factors and sediment attributes on the composition of comammox microorganisms and the abundance variations of ammonia oxidizers. Temperature and salinity were the most important contributing factors that shaped the comammox community. Further, detection of diverse comammox microorganisms in extremely high-salinity sediments suggested that this community could adapt to high salinity environments, which indicates salinity may not be a critical factor resulting in the absence of comammox microorganisms in open-ocean environments. This study expanded the current understanding of the diversity and niche preference of comammox in mangrove ecosystems, and further enhanced our understanding of adaptation potential of comammox communities.


Assuntos
Ecossistema , Salinidade , Amônia , Archaea , China , Nitrificação , Oxirredução , Filogenia , Temperatura
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