Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 488
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Ecotoxicol Environ Saf ; 190: 109993, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31869715

RESUMO

There is a data gap on occurrence and transport of antibiotics in river-estuary system, with limited understanding of their impact on aquatic environment. To gain insight into the antibiotic pollution in river-estuary system, 22 surface sediments and 5 wetland plants from Yang River and its estuary in Jiaozhou Bay were selected to explore the occurrence and transport of eight quinotone antibiotics (QNs), and their impacts on aquatic environment. Our results indicated that QNs were widely present in the sediments from Yang River and its estuary, with a range of 1.34-8.69 ng/g (average 4.46 ng/g) in Yang River and 0.99-10.86 ng/g (average 3.92 ng/g) in its estuary, respectively. No obvious correlations were observed between QNs values and TOC contents in sediments from our study area, due to low detective concentrations and frequencies of QNs. The mass loading of individual antibiotic from Yang River to its estuary was from 11.73 to 391.59 g/year, far below those from the other estuarine regions all over the world. QNs were observed in all five wetland plants, demonstrating that QNs contaminants could be taken up by wetland plants and providing the evidence that phytoremediation could be a feasible way to remove contaminants. Negative partial coefficients between individual antibiotic and brassicasterol biomarker suggested the presence of QNs inhibited the phytoplankton growth. Evaluation of ecological risk based on the values of risk quotients (RQs) showed that OFL in Yang River displayed medium risk for algae, and CIP and OFL in its estuary also displayed medium risk value for plant and algae. The results could provide powerful basis on controlling river antibiotics pollution to enhance rivers-estuary security in similar regions.


Assuntos
Antibacterianos/análise , Estuários , Quinolonas/análise , Rios/química , Poluentes Químicos da Água/análise , Antibacterianos/toxicidade , Baías , China , Sedimentos Geológicos/química , Fitoplâncton/efeitos dos fármacos , Plantas/química , Quinolonas/toxicidade , Poluentes Químicos da Água/toxicidade , Áreas Alagadas
2.
Environ Int ; 133(Pt A): 105175, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31629173

RESUMO

Herbicides have been increasingly used worldwide and a large amount of herbicide residue eventually enters the ocean via groundwater or surface run-off every year. However, the global coastal pollution status of herbicides and their negative impact on marine life (especially phytoplankton) in natural environmental concentrations are poorly understood except for few special environments (e.g. the Great Barrier Reef, Australia). Our field investigation of the distribution of ten triazine herbicides in the Bohai Sea and the Yellow Sea of China revealed that the concentrations of triazine herbicides exceeded the "No Observed Effect Concentrations" for phytoplankton. Their total concentrations could be as high as 6.61 nmol L-1. Based on the concentration addition model, the toxicity of herbicide homologues is usually cumulative, and the combined toxicity of these ten triazine herbicides could cause 13.2% inhibition on the chlorophyll a fluorescence intensity of a representative diatom species Phaeodactylum tricornutum Pt-1, which corresponds roughly to the toxicity of atrazine in an equivalent concentration of 14.08 nmol L-1. Atrazine in this equivalent-effect concentration could greatly inhibit the growth of cells, the maximum quantum efficiency of photosystem II (Fv/Fm), and nutrient absorption of Phaeodactylum tricornutum Pt-1. Transcriptome analysis revealed that multiple metabolic pathways (Calvin cycle, tricarboxylic acid (TCA) cycle, glycolysis/gluconeogenesis, etc.) related with photosynthesis and carbon metabolism were greatly disturbed, which might ultimately influence the primary productivity of coastal waters. Moreover, with the values of its bioaccumulation factor ranging from 69.6 to 118.9, atrazine was found to be accumulated in algal cells, which indicates that herbicide pollution might eventually affect the marine food web and even threaten the seafood safety of human beings.


Assuntos
Herbicidas/toxicidade , Fitoplâncton/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Atrazina/toxicidade , China , Clorofila A/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Fitoplâncton/metabolismo , Medição de Risco
3.
Mar Drugs ; 17(9)2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31484443

RESUMO

Phytoplankton are primary producers in the marine ecosystem, where phosphorus is often a limiting factor of their growth. Hence, they have evolved strategies to recycle phosphorus by replacing membrane phospholipids with phosphorus-free lipids. However, mechanisms for replacement of lipid classes remain poorly understood. To improve our understanding, we performed the lipidomic and transcriptomic profiling analyses of an oleaginous marine microalga Nannochloropsis sp. PJ12 in response to phosphorus depletion (PD) and replenishing. In this study, by using (liquid chromatography couple with tandem mass spectrometry) LC-MS/MS-based lipidomic analysis, we show that membrane phospholipid levels are significantly reduced upon PD, while phosphorus-free betaine lipid levels are increased. However, levels of phosphorus-free photosynthetic galactolipid and sulfolipid are not increased upon PD, consistent with the reduced photosynthetic activity. RNA-seq-based transcriptomic analysis indicates that enzymes involved in phospholipid recycling and phosphorus-free lipid synthesis are upregulated, supporting the lipidomic analysis. Furthermore, enzymes involved in FASII (type II fatty acid synthesis) elongation cycle upon PD are transcriptionally downregulated. EPA (eicosapentaenoic acid) level decrease upon PD is revealed by both GC-MS (gas chromatography coupled with mass spectrometry) and LC-MS/MS-based lipidomic analyses. PD-induced alteration is reversed after phosphorus replenishing. Taken together, our results suggest that the alteration of lipid classes upon environmental change of phosphorus is a result of remodeling rather than de novo synthesis in Nannochloropsis sp. PJ12.


Assuntos
Metabolismo dos Lipídeos/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Fósforo/farmacologia , Transcriptoma/efeitos dos fármacos , Cromatografia Líquida/métodos , Ácidos Graxos/genética , Perfilação da Expressão Gênica/métodos , Glicolipídeos/genética , Metabolismo dos Lipídeos/genética , Lipídeos/genética , Microalgas/genética , Fosfolipídeos/genética , Fotossíntese/efeitos dos fármacos , Fotossíntese/genética , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/genética , Espectrometria de Massas em Tandem/métodos , Transcriptoma/genética
4.
Mar Pollut Bull ; 146: 1002-1006, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426135

RESUMO

Because ferromanganese polymetallic crusts can become a global resource of valuable elements the ecological impact of seafloor crust mining requires evaluation. Whilst the detrimental impact on deep-ocean benthos is established, experimental evidence about the mining hazard to surface-ocean is sparse. When retrieved, mined crusts can leach elements potentially harmfull to the core oceanic CO2-fixers - phytoplankton. To directly assess the magnitude of this potential hazard at ocean-basin scale, we examine the impact of ore slurry on phytoplankton CO2 fixation along a meridional transect through the South Atlantic Ocean. Within 12 h crust slurry additions caused a 25% decrease of CO2 fixation in the subtropical region and 15% in the temperate-polar region. Such moderate susceptibility of phytoplankton indicates limited release of harmful elements from tested polymetallic powder. Although this implies that environmentally sustainable seafloor mining could be feasible, longer-term complex studies of the mining impact on the surface ocean are required.


Assuntos
Ciclo do Carbono/efeitos dos fármacos , Ferro/toxicidade , Manganês/toxicidade , Mineração , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/metabolismo , Poluentes Químicos da Água/toxicidade , Oceano Atlântico , Dióxido de Carbono/metabolismo , Água do Mar/química
5.
Chemosphere ; 234: 34-42, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31203039

RESUMO

Due to excessive loadings of nitrogen (N) and phosphorus (P), frequent blooms of harmful cyanobacteria and their associated cyanotoxins pose serious threats to recreational usage and human health. However, whether cyanobacteria growth and toxin production are limited by N, P, or both N + P is still not clear. Thus, we conducted a nutrient enrichment bioassay in situ in Spring Lake, a eutrophic lake in west Michigan, USA, to examine the influence of nutrient limitation on the proliferation of algal blooms and the production of microcystins (MC). N or P addition alone resulted in a slight increase in the concentration of chlorophyll-a (Chl-a), suggesting a positive effect on phytoplankton growth, but alone, neither were sufficient to induce algal blooms. In contrast, the combination of N and P had a significant and positive influence on phytoplankton growth and MC production. Compared to controls, the N + P treatment resulted in high concentrations of Chl-a and MC, as well as high pH and dissolved oxygen. In addition, significant increases were observed in different MC analogues for each treatment; the highest concentrations of intracellular MC-LR, -RR, -YR, and TMC (total MC) were found in the N + P treatment with values of 9.16, 6.10, 2.57, and 17.82 µg/L, respectively. This study suggests that at least in this temperate coastal lake, cyanobacterial blooms and associated MC are influenced more by combined N and P enrichment than by N or P alone, indicating that managing both nutrients is important for effectively reducing algal blooms and MC production.


Assuntos
Lagos/microbiologia , Microcistinas/metabolismo , Nitrogênio/farmacologia , Nutrientes/farmacologia , Fósforo/farmacologia , Fitoplâncton/crescimento & desenvolvimento , Carcinógenos/metabolismo , Eutrofização , Lagos/análise , Fitoplâncton/efeitos dos fármacos
6.
PLoS One ; 14(6): e0218924, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31237931

RESUMO

Propidium monoazide (PMA) is a highly selective dye that penetrates only membrane-compromised, dead microbial cells and inhibits both DNA extraction and amplification. PMA has been widely used for discrimination between living and dead microbial cells; however, the application of PMA in phytoplankton studies has been limited. In this study, we attempted to evaluate its applicability for the discrimination of viable phytoplankton. We tested PMA on seven phytoplankton species, Microcystis aeruginosa, Anabaena sp., Aphanizomenon sp., Synechocystis sp., Cryptomonas ovata, Scenedesmus obliquus, and Nitzschia apiculata as representatives of the major phytoplankton taxa Cyanobacteria (first four species), Chlorophyta, Cryptophyta, and Bacillariophyta, respectively. Our results showed that application of PMA to phytoplankton living in freshwater has the potential to distinguish viable from dead cells as in microbial studies. Particularly, PMA differentiated viable from dead cells in cyanobacterial species rather than in other phytoplankton taxa under our experimental conditions. However, our results also showed that it may be necessary to adjust various conditions affecting PMA treatment efficiency to expand its applicability to other phytoplankton. Although all factors contributing to the effects of PMA could not be evaluated, our study showed the applicability of PMA-based molecular approaches, which can be convenient quantitative methods for distinguishing living from dead phytoplankton in freshwater ecosystems. Setting optimal treatment conditions for other phytoplankton species may increase the efficacy of PMA-based molecular approaches.


Assuntos
Azidas/farmacologia , Fitoplâncton/efeitos dos fármacos , Propídio/análogos & derivados , DNA/efeitos dos fármacos , Ecossistema , Água Doce , Propídio/farmacologia
7.
Ecotoxicology ; 28(5): 559-568, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31123966

RESUMO

Previous field investigations implied a potential phosphorus (P)-limitation on the growth of phytoplankton in Daya Bay, a mesotrophic bay in the northern South China Sea. Using a total of 15 mesocosms (3 × 3 × 1.5 m, with ~10.8 m3 natural seawater containing phytoplankton assemblages for each), we found P-enrichment caused no obvious effect on phytoplankton (Chl a) growth across 8-day's cultivation in neither winter nor summer, while nitrogen (N)-enrichment greatly increased Chl a in both seasons. N plus P-enrichment further increased Chl a content. The N- or N plus P-enrichments increased the allocation of nano-Chl a but decreased micro-Chl a in most cases, with no obvious effect by P-alone. Coincided with nutrients effect on Chl a content, N- or N plus P-enrichments significantly enhanced the maximum photochemical quantum yield of Photosystem II (FV/FM) and maximum relative electron transport rate (rETRmax), but declined the non-photochemical quenching (NPQ), as well as the threshold for light saturation of electron transport (EK); again, P-enrichment had no significant effect. Moreover, the absorption cross section for PSII photochemistry (σPSII) and electron transport efficiency (α) increased due to N- or N plus P-enrichments, indicating the increased nutrients enhance the light utilization efficiency through promoting PSII light harvesting ability, and thus to enhance phytoplankton growth. Our findings indicate that N- or N plus P-enrichments rigorously fuel phytoplankton blooms regardless of N:P ratios, making a note of caution on the expected P-deficiency or P-limitation on the basis of Redfield N:P ratios in Daya Bay.


Assuntos
Monitoramento Ambiental , Fósforo/metabolismo , Fitoplâncton/crescimento & desenvolvimento , Poluentes Químicos da Água/metabolismo , Baías , China , Eutrofização , Nutrientes/metabolismo , Fitoplâncton/efeitos dos fármacos
8.
Mar Drugs ; 17(5)2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31035351

RESUMO

Seven previously unreported cyclonerane derivatives, namely, 3,7,11-trihydroxycycloneran-10-one, cycloneran-3,7,10,11-tetraol, cycloneran-3,7,11-triol, 11,12,15-trinorcycloneran-3,7,10-triol, 7,10S-epoxycycloneran-3,15-diol, 7,10R-epoxycycloneran-3,15-diol, and (10Z)-15-acetoxy-10-cycloneren-3,7-diol, were isolated in addition to the known (10Z)-cyclonerotriol, (10E)-cyclonerotriol, catenioblin C, and chokol E from the culture of Trichoderma asperellum A-YMD-9-2, an endophytic fungus obtained from the marine red alga Gracilaria verrucosa. The structures of previously unreported compounds were established by spectroscopic techniques, including 1D/2D NMR, MS, and IR. The isolation of these new cyclonerane derivatives greatly adds to the structural diversity of unusual cyclonerane sesquiterpenes, and several isolates exhibit potent inhibition against some marine phytoplankton species.


Assuntos
Endófitos/química , Gracilaria/microbiologia , Sesquiterpenos/química , Trichoderma/química , Animais , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Fitoplâncton/efeitos dos fármacos , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Zooplâncton/efeitos dos fármacos
9.
Arch Environ Contam Toxicol ; 77(1): 29-39, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31020372

RESUMO

Human activities have introduced a variety of chemicals, including pesticides, fertilizers, and salt, into the environment, which may have deleterious effects on the organisms inhabiting these areas. Amphibians are especially susceptible to absorption of chemical pollutants. To determine the possible combined effects of these chemicals on amphibian development and stress levels, Southern leopard frog (Lithobates sphenocephala) larvae were exposed to one of eight individual or combined treatments of atrazine, ammonium nitrate fertilizer, and sodium chloride salt. Stress levels, indicated by release of the stress hormone corticosterone, were measured premetamorphosis at week 8 of development. Water hormone samples were processed to analyze corticosterone levels. Changes in tadpole growth were determined by surface area measurements taken from biweekly photographs. The combined chemical treatment of atrazine, salt, and fertilizer had a significant interactive effect by increasing stress levels before metamorphosis (p = 0.003). After a month of larval development, tadpoles exposed to ammonium nitrate had larger surface area (p = 0.035). Tadpoles exposed to atrazine had a lower growth rate throughout larval development (p = 0.025) and the lowest number of individuals reaching metamorphosis at 33%. However, the frogs in the atrazine treatment that did successfully metamorphose did so in fewer days (p = 0.002). Because amphibians are exposed to multiple chemicals simultaneously in the environment, assessing the effects of a combination of contaminants is necessary to improve application strategies and ecosystem health.


Assuntos
Corticosterona/análise , Fertilizantes/toxicidade , Praguicidas/toxicidade , Rana pipiens/crescimento & desenvolvimento , Cloreto de Sódio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Atrazina/toxicidade , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/metabolismo , Metamorfose Biológica/efeitos dos fármacos , Nitratos/toxicidade , Perifíton/efeitos dos fármacos , Fitoplâncton/efeitos dos fármacos , Rana pipiens/metabolismo
10.
Ecotoxicol Environ Saf ; 176: 355-363, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30954621

RESUMO

The aim of this research was to assess the ecotoxicity of leachates originating from a niobium mine located in Canada. These tailings contain considerable amounts of carbonates and phosphates and could potentially be used as fertilizer for agriculture. However, the presence of different contaminants linked with the ores mined, including rare earth elements and daughter elements of the uranium disintegration chain is of concern. Bioassays have been used to determine if the tailings leachates could be harmful. The assessment of the toxicity of progressive dilutions of five tailing leachates (808, 809, 810, 811 and 897) was performed on different organisms: phytoplankton Raphidocelis subcapitata and duckweed Lemna minor, based on their growth and chlorophyll a content, and water flea Daphnia magna based on their mobility, mortality and reproduction. Overall, the leachates showed higher toxicity to Raphidocelis subcapitata and Lemna minor, than toward Daphnia magna. Leachate 808 showed no toxicity to all organisms while leachate 810 showed significant effects to all species. The results can be explained by the leachate dissolved metal or nutrient concentrations, but also by the metal bioavailability which depends on pH and hardness. Generally, toxicity was observed in undiluted samples tested, which is not representative of the conditions that could occur in the environment. This supports the idea that these tailings could be used as fertilizer albeit more studies may be required, particularly to assess the toxicity of the tailings leachate for benthic organisms, the toxicity of the tailings for terrestrial organisms and the variations of soil and sediment physicochemical properties after tailing treatments.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Mineração , Nióbio , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/metabolismo , Araceae/efeitos dos fármacos , Araceae/metabolismo , Disponibilidade Biológica , Canadá , Clorofila A/metabolismo , Daphnia/efeitos dos fármacos , Daphnia/metabolismo , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/metabolismo , Poluentes Químicos da Água/química
11.
Environ Pollut ; 249: 610-619, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30933758

RESUMO

Nowadays, the occurrence of a large volume of plastic litter in oceanic and coastal zones has increased concern about its impacts on marine organisms. The degradation of plastic polymers leads to the formation of smaller fragments at both micro and nano scale (<5 mm and <1 µm respectively). Nanoplastics (NPs), due to their smaller size and high specific surface area can establish colloidal interactions with marine microalgae, therefore potential toxicity can be led. . To assess this hypothesis, the aim of the present study is to examine the behaviour of polystyrene nanoparticles (PS NPs) of different sizes (50 and 100 nm) in marine water and their possible effects at different physiological and cellular levels in the marine diatom Phaeodactylum tricornutum. Different biomarkers and stress responses in P. tricornutum were analysed when organisms were exposed to environmentally relevant PS NPs concentrations between 0.1 and 50 mg L-1. Our results showed significant differences between controls and exposure microalgae, indicating toxicity. After 24 h, an increase in oxidative stress biomarkers, damage to the photosynthetic apparatus, DNA damage and depolarization of mitochondrial and cell membrane from 5 mg L-1 were observed. Further after 72 h the inhibition of population growth and chlorophyll content were observed. Examining effects the effects related to PS NPs size, the smallest (50 nm) induced greater effects at 24 h while bigger PS NPs (100 nm) at72 h. This bigger particles (100 nm) showed more stability (in size distribution and spherical form) in the different culture media assayed, when compared with the rest of particles used. Strong adsorption and/or internalization of PS NPs was confirmed through changes in cell complexity and cell size as well as the fluorescence of 100 nm fluoresbrite PS NPs after washing cell surface.


Assuntos
Diatomáceas/crescimento & desenvolvimento , Microalgas/efeitos dos fármacos , Nanopartículas/toxicidade , Fitoplâncton/crescimento & desenvolvimento , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Clorofila/metabolismo , Dano ao DNA/efeitos dos fármacos , Diatomáceas/efeitos dos fármacos , Diatomáceas/fisiologia , Água Doce , Membranas Mitocondriais/patologia , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/fisiologia , Água/metabolismo
12.
Fitoterapia ; 134: 372-377, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30878292

RESUMO

Eight new bisabolane derivatives, trichobisabolins A-H, along with two known ones, (3R,6R,7R)-1,10-bisaboladien-3-ol (9) and (3R,6R,7S)-1,10-bisaboladien-3,6-diol (10) were isolated from the culture of Trichoderma asperellum Y6-2, obtained from the surface of the marine red alga Chondrus ocellatus. Their structures and relative configurations were identified by interpretation of 1D/2D NMR and MS data. Compounds 1-8 were assayed for inhibiting the growth of some marine-derived organisms, including four marine phytoplankton species, one marine zooplankton species, and five pathogenic bacteria. All of them exhibited inhibition against the marine phytoplanktons with IC50 values ranging from 2.1-78 µg/mL, compounds 4 and 8 showed weak lethality to the marine zooplankton, and none of them had inhibition against the five pathogenic bacteria.


Assuntos
Bactérias/efeitos dos fármacos , Chondrus/microbiologia , Cicloexanos/farmacologia , Fitoplâncton/efeitos dos fármacos , Trichoderma/química , China , Cicloexanos/isolamento & purificação , Estrutura Molecular , Relação Estrutura-Atividade
13.
Environ Sci Pollut Res Int ; 26(15): 15011-15018, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30919190

RESUMO

The combined effect of polystyrene (PS) particles and triphenyltin chloride (TPTCl) to the green algae Chlorella pyrenoidosa was studied. The 96 h IC50 of TPTCl to the green algae C. pyrenoidosa was 30.64 µg/L. The toxicity of PS particles to C. pyrenoidosa was size-dependent, with the 96 h IC50 at 9.10 mg/L for 0.55 µm PS but no toxicity observed for 5.0 µm PS. The exposure to 0.55 µm PS led to damage on structure of algal cells, which could in turn cause inhibition on photosynthesis and population growth of the green algae. TPTCl concentrations in test medium were lowered by 15-19% at presence of 0.55 µm PS particles, indicating a reduced bioavailability of TPTCl. In spite of this reduced bioavailability, the presence of PS increased the toxicity of TPTCl, which might be attributed to facilitated uptake of TPTCl by the green algae after the damage of cell structure. The overall results of the present study provided important information on the effect of PS on the bioavailability and toxicity of TPTCl to phytoplankton species.


Assuntos
Chlorella/efeitos dos fármacos , Compostos Orgânicos de Estanho/toxicidade , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Disponibilidade Biológica , Chlorella/citologia , Chlorella/fisiologia , Ecotoxicologia/métodos , Compostos Orgânicos de Estanho/farmacocinética , Fotossíntese/efeitos dos fármacos , Fitoplâncton/efeitos dos fármacos
14.
Environ Pollut ; 247: 1089-1099, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30823338

RESUMO

Nitrogen accumulation in sediments, and the subsequent migration and transformations between sediment and the overlying water, plays an important role in the lake nitrogen cycle. However, knowledge of these processes are largely confined to ice-free seasons. Recent research under ice has mainly focused on the water eco-environmental effects during winter. Sediment N accumulation during the ice-on season and its associated eco-environmental impacts have never been systematically investigated. To address these knowledge gaps, we chose Wuliangsu Lake in China as a case study site, taking advantage of the spatial disparity between the 13 semi-separated sub-lakes. Based on samples of 35 sampling sites collected before, in the middle, and at the end of ice-on season separately, we performed a quantitative analysis of under-ice lake N accumulation and water-sediment N exchange by analyzing N fraction variations. Hierarchical Cluster Analysis and Relevance Analysis were used to help elucidate the main causes and implications of under-ice N variation. Our results clearly show that existing studies have underestimated the impact of under-ice N accumulation on the lake ecology throughout year: 1) Sediment N accumulated 2-3 times more than that before winter; 2) residual nitrogen (Res-N) contributed to the majority of the accumulated sediment N and was mainly induced by the debris of macrophytes; 3) total available nitrogen (TAN) was the most easily exchanged fractions between sediment and water, and it mainly affected the water environment during winter; 4) the Res-N accumulation during the ice-on season may have a strong impact on the eco-environment in the subsequent seasons. Our research is valuable for understanding the mechanism of internal nutrient cycle and controlling the internal nitrogen pollution, especially in shallow seasonally-frozen lakes that have long suffered from macrophyte-phytoplankton co-dominated eutrophication.


Assuntos
Monitoramento Ambiental/métodos , Eutrofização , Sedimentos Geológicos/análise , Lagos/química , Nitrogênio/análise , Fósforo/análise , Poluentes Químicos da Água/análise , China , Fitoplâncton/efeitos dos fármacos , Estações do Ano
15.
Lett Appl Microbiol ; 68(4): 360-368, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30843243

RESUMO

The antibiofilm activity of three hemibastadins analogues was evaluated against different marine bacterial strains through mono-species biofilms and through a multi-species model of biofilm. Results showed that compound 3 exhibited interesting antibiofilm efficiencies effective concentrations (EC50 ) in the range of 30-100 µmol l-1 without acute toxicity against bacteria. Toxicity against nontargeted organisms was also considered showing that the compound did not affect the global bacterial community at a concentration of 75-100 µmol l-1 . These results provided baseline data concerning the toxicity of antibiofilm biocides against marine organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reports relevant information about antibiofilm activity of original derivatives of hemibastadin alkaloids. The most active compound was shown to act as a specific anti-biofilm inhibitor without affecting viability of the targeted bacteria no more than those of the global bacterial community of a seawater sample. Taken together, these findings indicate the potentiality of such compounds to be used as original nonbiocidal molecules for designing eco-friendly antifouling solutions.


Assuntos
Biofilmes/efeitos dos fármacos , Desinfetantes/farmacologia , Oximas/farmacologia , Paracoccus/efeitos dos fármacos , Fenóis/farmacologia , Fitoplâncton/efeitos dos fármacos , Pseudoalteromonas/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Biofilmes/crescimento & desenvolvimento , Água do Mar/microbiologia , Navios
16.
Environ Sci Pollut Res Int ; 26(14): 14266-14276, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30864033

RESUMO

Ecosystem-based management is one of the strategies to protect the coastal areas. One of the key elements is phytoplankton community composition since it represents a good indicator of anthropogenic pressures. This identifies the seasonal patterns of phytoplankton, and its alterations by the stress factors induced by human activities are highly valuable. This research represents the first attempt to study that 476 km of western Mediterranean coastal belongs to the Valencian Community (Spain) based on the phytoplankton composition approach. The water samples during a 5-year period (6757 water samples) were taken to determine its phytoplankton group's dynamics and its relationship with anthropogenic stressors by means of a series of plots and statistical analyses. Diatoms are the group that most contribute to the whole community composition with two periods of maximum abundance. The Prasinophyceae and Cryptophyceae show unimodal patterns varying its maximum values depending on the season. The picocyanobacteria group exhibited the clearest and best-defined pattern. Other groups have no clear seasonal pattern and become abundant in areas of higher anthropogenic pressure. Graphical abstract Figure A contains poor quality of text in image. Otherwise, please provide replacement figure file.A new graphical abstract, with higher quality is attached.


Assuntos
Monitoramento Ambiental/métodos , Fitoplâncton/crescimento & desenvolvimento , Estações do Ano , Poluentes Químicos da Água/análise , Diatomáceas/classificação , Diatomáceas/efeitos dos fármacos , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Humanos , Estudos Longitudinais , Mar Mediterrâneo , Fitoplâncton/classificação , Fitoplâncton/efeitos dos fármacos , Água do Mar/química , Espanha
17.
Sci Total Environ ; 665: 982-994, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30790766

RESUMO

Even though empirical data supporting sound ecoregion-specific ecotoxicological evaluations are still scarce, the differences of environmental (including climatic) conditions in specific ecoregions are already currently being regulated for environmental risk assessment of pesticides in Europe. To shed new light on the ecotoxicological effects of pesticides on aquatic communities across ecoregions, the model pollutant pyrimethanil (fungicide) was tested in an outdoor mesocosm study with macrophyte-dominated communities in the European "South" (Portugal) and "Centre" (Germany) regulatory zones. Phytoplankton indicators monitored over 12 months indicated a low risk of the fungicide (0.73 or 0.77 mg pyrimethanil L-1, single application) to phytoplankton functioning; as expected since exposure simulated worst-case scenarios. However, the growth of key structural macroalgae and macrophytes was affected by the fungicide and negative effects occurred, especially in the Central zone experiment. Such effects were not detected earlier than approximately nine months post single pyrimethanil application. The presence or absence of such extremely long-lasting/delayed pyrimethanil effects depended on species, competitive situation, and ecoregion-specific physico-chemical environment. The present findings suggest that a better understanding of both direct and indirect effects of fungicide pollution on aquatic flora in two European ecoregions helps to consolidate the environmental risk assessment of pesticides in specific regulatory zones.


Assuntos
Fungicidas Industriais/toxicidade , Fitoplâncton/efeitos dos fármacos , Plantas/efeitos dos fármacos , Pirimidinas/toxicidade , Alga Marinha/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Alemanha , Portugal
18.
Environ Monit Assess ; 191(3): 130, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30725187

RESUMO

Seasonal water quality analysis helps to evaluate the impact of anthropogenic activities on reservoirs. The water quality may be judged by estimating various chemical parameters like dissolved oxygen (DO), free CO2, total alkalinity, total hardness, pH, Ca++, Mg++, Cl-, NO3-, SO4- bicarbonate, and total dissolved solids (TDS) along with environmental parameters like rainfall and temperature. Most of these abiotic factors are subject to human interventions and are interrelated. This cumulative effect directly influences the biota of the reservoir ecosystem where plankton communities are significant. The current work was carried out with the goal to understand the effect of abiotic factors on planktonic growth in a medium-sized artificial reservoir. The study was attempted to analyze two objectives, which were the variations of parameters with respect to three distinct seasons encountered in the region (summer, monsoon, and winter) and second being the impact of such varying parameters on countable/detectable planktonic diversity. From the water samples collected, 44 genera of planktons belonging to Cyanophyceae, Chlorophyceae, Dinophyceae, Desmids, Bacillariophyceae, and Euglenozoa were identified. There was a marked variation in the seasonal parameters pH, EC, temperature, CO2, and HCO3-. Comparison to the BIS and WHO values shows that though water is not potable, it can be used for agriculture and fishing. Thus, it is necessary that this predominantly rainfed reservoir be maintained for sustainable use.


Assuntos
Monitoramento Ambiental/métodos , Água Doce/química , Fitoplâncton/efeitos dos fármacos , Estações do Ano , Qualidade da Água , Biodiversidade , Índia , Fitoplâncton/classificação , Fitoplâncton/crescimento & desenvolvimento , Dinâmica Populacional , Temperatura Ambiente
19.
J Basic Microbiol ; 59(4): 385-391, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30706958

RESUMO

The effects of varying concentrations (ranging from 0 to 10 µM) of two different metals that is, iron (Fe) and copper (Cu) on indigenous bacterial populations and their hydrolytic enzyme activities within the bacterioplankton assemblages from the surface waters of the Kalamazoo River were examined under controlled microcosm conditions. The two metals were added to water samples collected from the Kalamazoo River and examined for bacterial abundance and leucine aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. Results revealed no concentration effects on the bacterial populations in the presence of both Fe and Cu, although the bacterial numbers varied significantly over time in both microcosms. Conversely, leucine aminopeptidase activities based on post-hoc tests using Bonferroni correction revealed significant differences to increasing concentrations of both metals over the study period. These results further validate previous knowledge regarding the importance of various metal ions in regulating bacterial community structures and also suggest that aminopeptidase have the potential of effectively functioning using diverse trace and heavy metals as extracellular peptidase cofactors in aquatic systems.


Assuntos
Bactérias/efeitos dos fármacos , Metais Pesados/farmacologia , Fitoplâncton/efeitos dos fármacos , Rios/microbiologia , Microbiologia da Água , Poluentes Químicos da Água/farmacologia , Bactérias/enzimologia , Bactérias/crescimento & desenvolvimento , Proteínas de Bactérias/análise , Cobre/metabolismo , Cobre/farmacologia , Ferro/metabolismo , Ferro/farmacologia , Leucil Aminopeptidase/análise , Metais Pesados/metabolismo , Michigan , Fitoplâncton/enzimologia , Fitoplâncton/crescimento & desenvolvimento , Rios/química , Poluentes Químicos da Água/metabolismo
20.
Sci Total Environ ; 663: 369-379, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30716627

RESUMO

We developed a three-dimensional model to study the dynamics of carbon dioxide (CO2) emission from a subtropical drinking water reservoir. The quantitative effects of dissolved CO2 concentration on phytoplankton growth were coupled in an inorganic carbon module. Water quality monitoring was carried out to calibrate and validate the model. The simulated surface CO2 concentrations showed no significant difference between seasons (p>0.05). Regarding the spatial distribution, high CO2 concentrations were observed in the inflow and dam regions (p<0.05). Four scenarios of different atmospheric CO2 pressures and eutrophic levels were simulated to test the following hypotheses: (1) eutrophication will reverse the carbon budgets in reservoir systems and (2) rising CO2 levels will increase phytoplankton biomass. The results showed that water quality improvements will promote the emission of CO2 into the atmosphere. Simultaneously, the elevated CO2 in the air will stimulate algal biomass, especially in nutrient-rich systems. The systematic analysis of carbon cycling revealed the different internal transformation rates under different scenarios and showed that 32% of carbon was removed via CO2 emission and carbon burial. The interaction provides a novel direction to understand the feedback loops between aquatic ecosystems and increasing CO2 pressure in the future.


Assuntos
Dióxido de Carbono/análise , Água Potável/análise , Eutrofização , Fitoplâncton/fisiologia , Biomassa , China , Modelos Biológicos , Fitoplâncton/efeitos dos fármacos , Recursos Hídricos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA