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1.
Chemosphere ; 240: 124938, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574444

RESUMO

Clearwater Mesa (James Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L-1. Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Minerais/análise , Compostos Orgânicos/análise , Oligoelementos/análise , Regiões Antárticas , Carbonatos/análise , Mudança Climática , Ecossistema , Camada de Gelo/química , Chumbo/análise , Trinidad e Tobago , Tempo (Meteorologia) , Zinco/análise
2.
J Environ Sci (China) ; 87: 389-397, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791511

RESUMO

Carbonaceous matter has an important impact on glacial retreat in the Tibetan Plateau, further affecting the water resource supply. However, the related studies on carbonaceous matter are still scarce in Geladaindong (GLDD) region, the source of the Yangtze River. Therefore, the concentration, source and variations of carbonaceous matter at Ganglongjiama (GLJM) glacier in GLDD region were investigated during the melting period in 2017, which could deepen our understanding on carbonaceous matter contribution to glacier melting. The results showed that dissolved organic carbon (DOC) concentration of snowpit samples (283 ±â€¯200 µg/L) was much lower than that of precipitation samples (624 ±â€¯361 µg/L), indicating that large parts of DOC could be rapidly leached from the snowpit during the melting process. In contrast, refractory black carbon (rBC) concentration measured by Single Particle Soot Photometer of snowpit samples (4.27 ±â€¯3.15 µg/L) was much higher than that of precipitation samples (0.97 ±â€¯0.49 µg/L). Similarly, DOC with high mass absorption cross-section measured at 365 nm value was also likely to enrich in snowpit during the melting process. In addition, it was found that both rBC and DOC with high light-absorbing ability began to leach from the snowpit when melting process became stronger. Therefore, rBC and DOC with high light-absorbing ability exhibited similar behavior during the melting process. Based on relationship among DOC, rBC and K+ in precipitation, the main source of carbonaceous matter in GLJM glacier was biomass burning during the study period.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Rios/química , Biomassa , Carbono , Fracionamento Químico , Camada de Gelo/química , Fuligem
3.
Nat Ecol Evol ; 3(12): 1675-1685, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31740846

RESUMO

Glaciers cover about 10% of the Earth's land area but they are retreating rapidly and many will disappear within decades. Glacier retreat is a worldwide phenomenon increasing the threat to water resources, biodiversity and associated ecosystem services for hundreds of millions of people, mostly in developing countries. Our understanding of the ecological consequences of glacier retreat has improved significantly in the past decade, but we still lack a comprehensive framework for predicting biodiversity responses to glacier retreat globally, across diverse habitats and taxa. By conducting a global meta-analysis of 234 published studies, including more than 2,100 biodiversity surveys covering marine, freshwater and terrestrial assemblages, we show here that taxon abundance and richness generally increase at lower levels of glacier influence, suggesting that diversity increases locally as glaciers retreat. However, significant response heterogeneity was observed between study sites and species: 6-11% of the studied populations, particularly in fjords, would lose out from glacier retreat. Most of the losers are specialist species, efficient dispersers, uniquely adapted to glacial conditions, whereas the winners are generalist taxa colonizing from downstream. Our global analyses also identify key geographic variables (glacier cover, isolation and melting rates, but not latitude or altitude) and species traits (body size and trophic position) likely to modulate taxon sensitivity to glacial retreat. Finally, we propose mechanistic diagrams for model development to predict biodiversity change following glacier retreat.


Assuntos
Ecossistema , Camada de Gelo , Biodiversidade , Ecologia
4.
Zootaxa ; 4664(2): zootaxa.4664.2.7, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31716681

RESUMO

Andiperla morenensis n. sp. is described from the Perito Moreno Glacier, Santa Cruz Province, Argentina. The new species differs from its only congener, A. willinki, Aubert, 1956 by tergum X produced into an acute lobe directed posteriorly and by the presence of a small epiproct. The18S rRNA and COI gene sequence of A. morenensis n. sp. is provided.


Assuntos
Camada de Gelo , Lepidópteros , Animais , Argentina , Neópteros
5.
Mar Pollut Bull ; 145: 306-315, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590792

RESUMO

Understanding the fate of spilled oil in cold environments is essential for oil spill response in Arctic areas. The potential for oils to adhere to sea ice and mechanical skimmers can significantly impact the success of oil spill response and influence the fate of oil in the marine environment. Therefore, the affinity of oil to sea ice and skimmer material was quantified experimentally for three different types of oils at various degrees of weathering. Contact angle measurements of crude oil droplets were performed on the top of and under sea ice and polyethylene-based skimmer material, being submerged in seawater (-2 °C). In addition, "dip- and refloat" tests were performed to quantify the adhesion and study the re-floating process of oil from sea ice at -2 °C (moist ice) and -20 °C (cold dry ice), and from a skimmer material prior to and subsequently to its submersion in seawater (-2 °C). The results indicated limited interaction of oils with sea ice submerged in seawater, but a strong affinity of oils towards polyethylene-based skimmer material.


Assuntos
Camada de Gelo/química , Petróleo , Polietileno/química , Água do Mar/química , Poluentes Químicos da Água/química , Regiões Árticas , Poluição por Petróleo/análise
6.
Mar Pollut Bull ; 145: 463-473, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590811

RESUMO

Microplastics (plastic particles <5 mm) are an emerging concern in Arctic sea ice with measured concentrations orders of magnitude higher than in surface seawater. However, incorporation of microplastics into sea ice, and their impact on sea ice properties, is unknown. We added microplastic particles in a microcosm experiment to determine microplastic distributions and effects on sea ice properties. Microplastic additions did not affect sea ice growth, but high concentrations of microplastics at the ice surface resulted in high ice salinity and changes in sea ice albedo. Field studies in the Gulf of Bothnia (Baltic Sea) showed sea ice concentration of microplastics from 8 to 41 particles per liter of melted ice, wich were much lower than those found to impact sea ice properties in the microcosm experiments. However, should microplastic concentrations increase, microplastic incorporation in sea ice may impact sea ice albedo.


Assuntos
Camada de Gelo/química , Plásticos/análise , Água do Mar/análise , Regiões Árticas , Países Bálticos , Monitoramento Ambiental , Poluentes Químicos da Água/análise
7.
Nature ; 574(7777): 237-241, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31578526

RESUMO

Earth is heading towards a climate that last existed more than three million years ago (Ma) during the 'mid-Pliocene warm period'1, when atmospheric carbon dioxide concentrations were about 400 parts per million, global sea level oscillated in response to orbital forcing2,3 and peak global-mean sea level (GMSL) may have reached about 20 metres above the present-day value4,5. For sea-level rise of this magnitude, extensive retreat or collapse of the Greenland, West Antarctic and marine-based sectors of the East Antarctic ice sheets is required. Yet the relative amplitude of sea-level variations within glacial-interglacial cycles remains poorly constrained. To address this, we calibrate a theoretical relationship between modern sediment transport by waves and water depth, and then apply the technique to grain size in a continuous 800-metre-thick Pliocene sequence of shallow-marine sediments from Whanganui Basin, New Zealand. Water-depth variations obtained in this way, after corrections for tectonic subsidence, yield cyclic relative sea-level (RSL) variations. Here we show that sea level varied on average by 13 ± 5 metres over glacial-interglacial cycles during the middle-to-late Pliocene (about 3.3-2.5 Ma). The resulting record is independent of the global ice volume proxy3 (as derived from the deep-ocean oxygen isotope record) and sea-level cycles are in phase with 20-thousand-year (kyr) periodic changes in insolation over Antarctica, paced by eccentricity-modulated orbital precession6 between 3.3 and 2.7 Ma. Thereafter, sea-level fluctuations are paced by the 41-kyr period of cycles in Earth's axial tilt as ice sheets stabilize on Antarctica and intensify in the Northern Hemisphere3,6. Strictly, we provide the amplitude of RSL change, rather than absolute GMSL change. However, simulations of RSL change based on glacio-isostatic adjustment show that our record approximates eustatic sea level, defined here as GMSL unregistered to the centre of the Earth. Nonetheless, under conservative assumptions, our estimates limit maximum Pliocene sea-level rise to less than 25 metres and provide new constraints on polar ice-volume variability under the climate conditions predicted for this century.


Assuntos
Água do Mar/análise , Dióxido de Carbono/análise , Foraminíferos/química , Sedimentos Geológicos/química , História Antiga , Camada de Gelo/química , Nova Zelândia , Oceanos e Mares , Isótopos de Oxigênio/análise , Pressão Parcial
8.
Environ Sci Technol ; 53(21): 12565-12575, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31566955

RESUMO

Ice cores are climate archives suitable for the reconstruction of past atmospheric composition changes. Ice core analysis provides valuable insight into the chemical nature of aerosols and enables constraining emission inventories of primary emissions and of gas-phase precursors. Changes in the emissions of volatile organic compounds (VOCs) can affect formation rates and mechanisms as well as chemical composition of aerosols during the preindustrial era, key information for understanding aerosol climate effects. Here, we present an analytical method for the reconstruction of organic aerosol composition preserved in glacier ice cores. A solid-phase-extraction method, optimized toward oxidation products of biogenic VOCs, provides an enrichment factor of ∼200 and quantitative recovery for compounds of interest. We applied the preconcentration method on ice core samples from the high-alpine Fiescherhorn glacier (Swiss Alps), and used high-performance liquid chromatography coupled to high-resolution mass spectrometry as a sensitive detection method. We describe a nontarget analysis that screens for organic molecules in the ice core samples. We evaluate the atmospheric origin of the detected compounds in the ice by molecular-resolved comparison with airborne particulate matter samples from the nearby high-alpine research station Jungfraujoch. The presented method is able to shed light upon the history of the evolution of organic aerosol composition in the anthropocene, a research field in paleoclimatology with considerable potential.


Assuntos
Camada de Gelo , Compostos Orgânicos Voláteis , Aerossóis , Espectrometria de Massas , Material Particulado
9.
J Basic Microbiol ; 59(11): 1065-1081, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31556143

RESUMO

In the current study, psychrophilic, endolithic, and epilithic bacterial strains were isolated and characterized from the nonpolar Laohugou glacier (LHG) no. 12, the largest valley glacier in the western Qilian Mts. located on the northeastern edge of the Tibetan Plateau. Five different types of samples, rocks, soil, glacial water, ice/snow, and cryoconite, were collected. A total of 48 bacterial strains were isolated by using the R2A bacterial cultural medium. The findings revealed that the Gram-positive bacteria 41 (85.4%) dominated the Gram-negative bacteria 7 (14.6%) in this extremely harsh environment. Molecular characterization based on 16S ribosomal RNA gene sequencing exhibited that the obtained isolates belong to four phyla, among which the diversity of Firmicutes (58.33%) was higher followed by Actinobacteria (23.0%), Proteobacteria (14.6%), and least diversity was reported in Euryarchaeota (4.2%). The bacterial communities were most dominant in soil samples followed by cryoconite sample and least dominant in the ice and snow samples. Moreover, the obtained bacterial isolates were found resistant to high concentrations of heavy metals (Cr3+ , Cd2+ , Hg2+ , and Ar3+ ) and sodium chloride, and, therefore, exhibited polyextremophilic characteristics. LHG no. 12 is rich in bacterial and archaeal diversities and provides a potentially curious site for further in-depth exploration of microbial diversity and their biotechnological applications.


Assuntos
Bactérias/classificação , Bactérias/efeitos dos fármacos , Biodiversidade , Camada de Gelo/microbiologia , Metais Pesados/metabolismo , Microbiologia do Solo , Archaea/classificação , Archaea/genética , Bactérias/genética , Meios de Cultura , Extremófilos , Metais Pesados/farmacologia , Filogenia , RNA Ribossômico 16S/genética , Tibet
11.
Environ Sci Technol ; 53(21): 12207-12217, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31525918

RESUMO

Globally, alpine glaciers hold a large quantity of dissolved organic matter (DOM) and are headwaters of numerous rivers supporting downstream heterotrophic metabolism. However, it remains unclear how glacial coverage and distance from the glacial terminus affect the fate of DOM. Here, we elucidate DOM variability in glacial-fed streams on the Tibetan Plateau using field sampling and bioincubation experiments and compare our findings with the existing literature. We found that dissolved organic carbon, DOM absorption a(254), DOM aromaticity, and the relative abundance of lignin compounds in glacial-fed streams and rivers all increased with increasing distance from the glacial terminus and with decreasing glacial coverage. We also found that contribution of protein-like components, the relative abundance of aliphatic compounds, and DOM biolability increased with increasing glacial coverage and with decreasing distance from the glacial terminus. The ratio of glacial coverage to the logarithmic transformed distance from the glacial terminus was better than that of actual glacial coverage and distance from the glacial terminus in tracing the variability of glacial-fed stream DOM. Microbes in surface ice can produce biolabile DOM that is exported downstream with meltwater. This glacial-fed stream and river DOM is an important source of the highly bioavailable material fueling downstream heterotrophic activity.


Assuntos
Ecossistema , Rios , Carbono , Camada de Gelo , Tibet
13.
Nature ; 574(7777): 233-236, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31471591

RESUMO

Reconstructing the evolution of sea level during past warmer epochs such as the Pliocene provides insight into the response of sea level and ice sheets to prolonged warming1. Although estimates of the global mean sea level (GMSL) during this time do exist, they vary by several tens of metres2-4, hindering the assessment of past and future ice-sheet stability. Here we show that during the mid-Piacenzian Warm Period, which was on average two to three degrees Celsius warmer than the pre-industrial period5, the GMSL was about 16.2 metres higher than today owing to global ice-volume changes, and around 17.4 metres when thermal expansion of the oceans is included. During the even warmer Pliocene Climatic Optimum (about four degrees Celsius warmer than pre-industrial levels)6, our results show that the GMSL was 23.5 metres above the present level, with an additional 1.6 metres from thermal expansion. We provide six GMSL data points, ranging from 4.39 to 3.27 million years ago, that are based on phreatic overgrowths on speleothems from the western Mediterranean (Mallorca, Spain). This record is unique owing to its clear relationship to sea level, its reliable U-Pb ages and its long timespan, which allows us to quantify uncertainties on potential uplift. Our data indicate that ice sheets are very sensitive to warming and provide important calibration targets for future ice-sheet models7.


Assuntos
Mudança Climática/história , Água do Mar/análise , Calibragem , Dióxido de Carbono/análise , Foraminíferos/química , História Antiga , Camada de Gelo/química , Ilhas , Mar Mediterrâneo , Isótopos de Oxigênio/análise , Espanha , Incerteza
14.
Ecology ; 100(12): e02885, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31498888

RESUMO

The study of community succession is one of the oldest pursuits in ecology. Challenges remain in terms of evaluating the predictability of succession and the reliability of the chronosequence methods typically used to study community development. The research of William S. Cooper in Glacier Bay National Park is an early and well-known example of successional ecology that provides a long-term observational data set to test hypotheses derived from space-for-time substitutions. It also provides a unique opportunity to explore the importance of historical contingencies and as an example of a revitalized historical study system. We test the textbook successional trajectory in Glacier Bay and evaluate long-term plant community development via primary succession through extensive fieldwork, remote sensing, dendrochronological methods, and newly discovered data that fills in data gaps (1940s to late 1980s) in continuous measurement over 100+ years. To date, Cooper's quadrats do not support the classic facilitation model of succession in which a sequence of species interacts to form predictable successional trajectories. Rather, stochastic early community assembly and subsequent inhibition have dominated; most species arrived shortly after deglaciation and have remained stable for 50+ years. Chronosequence studies assuming prior composition are thus questionable, as no predictable species sequence or timeline was observed. This underscores the significance of assumptions about early conditions in chronosequences and the need to defend such assumptions. Furthermore, this work brings a classic study system in ecology up to date via a plot size expansion, new baseline biogeochemical data, and spatial mapping for future researchers for its second century of observation.


Assuntos
Ecologia , Ecossistema , Camada de Gelo , Plantas , Reprodutibilidade dos Testes
15.
Int J Syst Evol Microbiol ; 69(12): 3812-3817, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31483240

RESUMO

A Gram-stain-negative, aerobic, rod-shaped, devoid of flagella, orange-yellow-coloured bacterium (strain LB2P22T) was isolated from an ice sample collected from the Laigu glacier on the Tibetan Plateau, PR China. The results of 16S rRNA gene sequence analysis indicated that strain LB2P22T belongs to the genus Flavobacterium with highest similarity to Flavobacterium laiguense LB2P30T (98.14 %), Flavobacterium glaciei CGMCC 1.5380T (98.02 %), Flavobacterium psychroterrae CCM 8827T (97.94 %) and Flavobacterium granuli CGMCC 1.10125T (97.91 %). Strain LB2P22T had 77.99-84.99 % average nucleotide identity and 22.3-29.3 % digital DNA-DNA hybridization values with its closest relatives, indicating that it represents a novel species of the genus Flavobacterium. Strain LB2P22T grew at 0-25 °C, pH 7.0-8.0 and up to 1.0 % (w/v) NaCl. The main cellular fatty acids were iso-C15 : 0, summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) and anteiso-C15 : 0. The genomic DNA G+C content is 34.3 mol%. The predominant menaquinone was MK-6 and the polar lipids were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. Based on these data, a novel species, Flavobacteriumranwuense sp. nov., is proposed, with LB2P22T (=CGMCC 1.11361T=NBRC 113777T) as the type strain.


Assuntos
Flavobacterium/classificação , Camada de Gelo/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacterium/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfatidiletanolaminas/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
16.
Int J Syst Evol Microbiol ; 69(11): 3519-3523, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31483241

RESUMO

A Gram-stain-positive, rod-shaped and motile bacterium with lateral flagellum, designated T3246-1T, was isolated from an ice core, which was drilled from Hariqin Glacier on the Tibetan Plateau, PR China. It grew optimally at 20 °C, pH 7-8 and in the presence of 3 % (w/v) NaCl. The major fatty acid of strain T3246-1T was anteiso-C15 : 0. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. MK-8 was the dominant isoprenoid quinone. The whole-cell sugars were rhamnose, xylose and mannose. The major cell-wall peptidoglycan was lysine. The genomic DNA G+C content of the strain was 71.4 mol%. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain T3246-1T formed a lineage within the genus Haloactinobacterium and was closely related to Haloactinobacterium album YIM 93306T with 95.99 % similarity. The average nucleotide identity value between strain T3246-1T and Haloactinobacterium album YIM 93306T was 76.65 %. Based on phenotypic and chemotaxonomic characteristics, strain T3246-1T was considered to represent a novel species of the genus Haloactinobacterium, for which the name Haloactinobacterium glacieicola sp. nov. is proposed. The type strain is T3246-1T (=CGMCC 1.13535T=JCM 32923T).


Assuntos
Actinobacteria/classificação , Camada de Gelo/microbiologia , Filogenia , Actinobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , China , DNA Bacteriano/genética , Ácidos Graxos/química , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
17.
J Environ Radioact ; 208-209: 106039, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31491585

RESUMO

An alpine ice core, extracted from the Adamello glacier (Central Italian Alps), was analyzed in its entire length through low background γ-spectroscopy, for the detection of 137Cs. Our results show that in glacier ice 137Cs is tightly bound to insoluble particulate matter inside the ice core, and it is therefore possible to restrict γ-spectroscopy analysis to particulate matter only. We show how the sensibility of the detection limit can be improved by almost one order of magnitude by using a well-type detector instead of a coaxial one. Hypothesis on the dating of some radioactive layers are also hereby presented.


Assuntos
Radioisótopos de Césio/análise , Camada de Gelo/química , Monitoramento de Radiação , Poluentes Radioativos/análise , Itália
18.
Environ Pollut ; 254(Pt A): 112974, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31376600

RESUMO

Moss is usually as an initial colonizer in alpine glacier retreated regions. We hypothesized that moss can significantly facilitate the toxic metals accumulation in alpine ecosystems based on its strong ability of absorption and the role in soil development. Hence, we investigated the trace element pool sizes and enrichment factors, especially for mercury (Hg) by using the Hg isotopic compositions to determine the source contributions in a moss-dominated ecosystem over glacial erratic in Eastern Tibetan Plateau. Results show that Hg, lead (Pb) and cadmium (Cd) are highly enriched in organic soils. Specifically, Cd concentration is 5-20 times higher than the safety limit of the acid soil (pH ≤ 5.5) in China. Atmospheric depositions dominantly contribute to the Pb and Cd sources in organic soils, and followed by the moraine particles influences. The lowering pH in organic soils increasing with glacial retreated time results in the desorption of Cd in organic soils. Atmospheric Hg0 uptake by moss predominantly contributes to the Hg sources in organic soils. The average Pb accumulation rate over last 125-year is about 5.6 ±â€¯1.0 mg m-2 yr-1, and for Cd is 0.4 ±â€¯0.1 mg m-2 yr-1, and for Hg0 is 27.6 ±â€¯3.2 µg m-2 yr-1. These elevated accumulation rates are caused by the high moss biomass and elevated atmospheric Hg, Pb and Cd pollution levels in China and neighbouring regions. Our study indicates that the moss not only as the bioindicator, but also plays an important role in the hazardous metal biogeochemical cycling in alpine regions.


Assuntos
Briófitas/metabolismo , Cádmio/análise , Monitoramento Ambiental/métodos , Chumbo/análise , Mercúrio/análise , Poluentes do Solo/análise , Biodegradação Ambiental , China , Ecossistema , Poluição Ambiental/análise , Camada de Gelo/química , Metais Pesados/análise , Solo/química , Oligoelementos/análise
19.
J Basic Microbiol ; 59(9): 879-889, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31339587

RESUMO

Metallothionein (MT) is a low-molecular-weight protein with a high metal binding capacity and plays a key role in organism adaptation to heavy metals. In this study, a metallothionein gene was successfully cloned and sequenced from Antarctic sea-ice yeast Rhodotorula mucilaginosa AN5. Nucleotide sequencing and analysis revealed that the gene had four exons interrupted by three introns. MTs complementary DNA (named as RmMT) had an open reading frame of 321 bp encoding a 106 amino acid protein with a predicted molecular weight of 10.3 kDa and pI of 8.49. The number of amino acids and distribution of cysteine residues indicated that RmMT was a novel family of fungal MTs. Quantitative real-time polymerase chain reaction analysis showed that RmMT expression was elevated under copper-induced stress. The RmMT gene was transferred into E. coli and the RmMT expressing bacteria showed improved tolerance to copper ion and increased accumulation of heavy metals, such as Cu2+ , Pb2+ , Zn2+ , Cd2+ , and Ag+ . Moreover, in vitro studies, purified recombinant RmMT demonstrated that it could be used as a good scavenger of superoxide anion, hydroxyl, and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals. In summary, these results demonstrate that RmMT plays a key role in the tolerance and bioaccumulation of heavy metals.


Assuntos
Camada de Gelo/microbiologia , Metalotioneína/genética , Metalotioneína/metabolismo , Metais Pesados/metabolismo , Rhodotorula/genética , Adaptação Fisiológica/genética , Regiões Antárticas , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Sequência de Bases , Clonagem Molecular , Cobre/metabolismo , Escherichia coli/genética , Escherichia coli/fisiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/metabolismo , Expressão Gênica , Metalotioneína/isolamento & purificação , Fases de Leitura Aberta , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Rhodotorula/fisiologia
20.
Environ Pollut ; 253: 297-301, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323612

RESUMO

Contamination by plastic debris has been documented in most regions of the world, but their occurrence in high mountain areas has not been investigated to date. Here we present the first report of the occurrence and amount of microplastic in any terrestrial glacier environment. In the supraglacial debris of the Forni Glacier (Italian Alps), we observed the occurrence of (mean ±â€¯standard error) 74.4 ±â€¯28.3 items kg-1 of sediment (dry weight). This amount is within the range of variability of microplastic contamination observed in marine and coastal sediments in Europe. Most plastic items were made by polyesters, followed by polyamide, polyethylene and polypropylene. We estimated that the whole ablation area of Forni Glacier should host 131-162 million plastic items. Microplastic can be released directly into high elevation areas by human activities in the mountain or be transported by wind to high altitude. The occurrence of microplastic on Forni Glacier may be due to the gathering of debris coming from the large accumulation area into the relatively smaller ablation area of the glacier, as a consequence of its flow and melting.


Assuntos
Monitoramento Ambiental , Camada de Gelo , Plásticos/análise , Poluentes Químicos da Água/análise , Europa (Continente) , Polietileno , Resíduos/análise , Vento
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