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1.
Oecologia ; 192(3): 671-685, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32052180

RESUMO

Warming-induced nutrient enrichment in the Arctic may lead to shifts in leaf-level physiological properties and processes with potential consequences for plant community dynamics and ecosystem function. To explore the physiological responses of Arctic tundra vegetation to increasing nutrient availability, we examined how a set of leaf nutrient and physiological characteristics of eight plant species (representing four plant functional groups) respond to a gradient of experimental nitrogen (N) and phosphorus (P) enrichment. Specifically, we examined a set of chlorophyll fluorescence measures related to photosynthetic efficiency, performance and stress, and two leaf nutrient traits (leaf %C and %N), across an experimental nutrient gradient at the Arctic Long Term Ecological Research site, located in the northern foothills of the Brooks Range, Alaska. In addition, we explicitly assessed the direct relationships between chlorophyll fluorescence and leaf %N. We found significant differences in physiological and nutrient traits between species and plant functional groups, and we found that species within one functional group (deciduous shrubs) have significantly greater leaf %N at high levels of nutrient addition. In addition, we found positive, saturating relationships between leaf %N and chlorophyll fluorescence measures across all species. Our results highlight species-specific differences in leaf nutrient traits and physiology in this ecosystem. In particular, the effects of a gradient of nutrient enrichment were most prominent in deciduous plant species, the plant functional group known to be increasing in relative abundance with warming in this ecosystem.


Assuntos
Ecossistema , Tundra , Alaska , Regiões Árticas , Nutrientes
2.
Nat Commun ; 11(1): 1001, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081890

RESUMO

Human activity has caused dramatic population declines in many wild species. The resulting bottlenecks have a profound impact on the genetic makeup of a species with unknown consequences for health. A key genetic factor for species survival is the evolution of deleterious mutation load, but how bottleneck strength and mutation load interact lacks empirical evidence. We analyze 60 complete genomes of six ibex species and the domestic goat. We show that historic bottlenecks rather than the current conservation status predict levels of genome-wide variation. By analyzing the exceptionally well-characterized population bottlenecks of the once nearly extinct Alpine ibex, we find genomic evidence of concurrent purging of highly deleterious mutations but accumulation of mildly deleterious mutations. This suggests that recolonization bottlenecks induced both relaxed selection and purging, thus reshaping the landscape of deleterious mutation load. Our findings highlight that even populations of ~1000 individuals can accumulate mildly deleterious mutations. Conservation efforts should focus on preventing population declines below such levels to ensure long-term survival of species.


Assuntos
Cabras/genética , Mutação , Animais , Animais Selvagens/classificação , Animais Selvagens/genética , Simulação por Computador , Conservação dos Recursos Naturais , Evolução Molecular , Variação Genética , Genética Populacional , Genoma , Cabras/classificação , Modelos Genéticos , Especificidade da Espécie , Tundra
3.
Ambio ; 49(3): 666-677, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31955396

RESUMO

Vegetation change has consequences for terrestrial ecosystem structure and functioning and may involve climate feedbacks. Hence, when monitoring ecosystem states and changes thereof, the vegetation is often a primary monitoring target. Here, we summarize current understanding of vegetation change in the High Arctic-the World's most rapidly warming region-in the context of ecosystem monitoring. To foster development of deployable monitoring strategies, we categorize different kinds of drivers (disturbances or stresses) of vegetation change either as pulse (i.e. drivers that occur as sudden and short events, though their effects may be long lasting) or press (i.e. drivers where change in conditions remains in place for a prolonged period, or slowly increases in pressure). To account for the great heterogeneity in vegetation responses to climate change and other drivers, we stress the need for increased use of ecosystem-specific conceptual models to guide monitoring and ecological studies in the Arctic. We discuss a conceptual model with three hypothesized alternative vegetation states characterized by mosses, herbaceous plants, and bare ground patches, respectively. We use moss-graminoid tundra of Svalbard as a case study to discuss the documented and potential impacts of different drivers on the possible transitions between those states. Our current understanding points to likely additive effects of herbivores and a warming climate, driving this ecosystem from a moss-dominated state with cool soils, shallow active layer and slow nutrient cycling to an ecosystem with warmer soil, deeper permafrost thaw, and faster nutrient cycling. Herbaceous-dominated vegetation and (patchy) bare ground would present two states in response to those drivers. Conceptual models are an operational tool to focus monitoring efforts towards management needs and identify the most pressing scientific questions. We promote greater use of conceptual models in conjunction with a state-and-transition framework in monitoring to ensure fit for purpose approaches. Defined expectations of the focal systems' responses to different drivers also facilitate linking local and regional monitoring efforts to international initiatives, such as the Circumpolar Biodiversity Monitoring Program.


Assuntos
Ecossistema , Tundra , Regiões Árticas , Mudança Climática , Solo , Svalbard
4.
Ambio ; 49(3): 732-748, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31955397

RESUMO

Tundra-breeding birds face diverse conservation challenges, from accelerated rates of Arctic climate change to threats associated with highly migratory life histories. Here we summarise the status and trends of Arctic terrestrial birds (88 species, 228 subspecies or distinct flyway populations) across guilds/regions, derived from published sources, raw data or, in rare cases, expert opinion. We report long-term trends in vital rates (survival, reproduction) for the handful of species and regions for which these are available. Over half of all circumpolar Arctic wader taxa are declining (51% of 91 taxa with known trends) and almost half of all waterfowl are increasing (49% of 61 taxa); these opposing trends have fostered a shift in community composition in some locations. Declines were least prevalent in the African-Eurasian Flyway (29%), but similarly prevalent in the remaining three global flyways (44-54%). Widespread, and in some cases accelerating, declines underscore the urgent conservation needs faced by many Arctic terrestrial bird species.


Assuntos
Aves , Tundra , Animais , Regiões Árticas , Mudança Climática , Reprodução
5.
Proc Natl Acad Sci U S A ; 117(6): 3026-3033, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31988125

RESUMO

The Arctic climate was warmer than today at the last interglacial and the Holocene thermal optimum. To reveal the impact of past climate-warming events on the demographic history of an Arctic specialist, we examined both mitochondrial and nuclear genomic variation in the collared lemming (Dicrostonyx torquatus, Pallas), a keystone species in tundra communities, across its entire distribution in northern Eurasia. The ancestral phylogenetic position of the West Beringian group and divergence time estimates support the hypothesis of continental range contraction to a single refugial area located in West Beringia during high-magnitude warming of the last interglacial, followed by westward recolonization of northern Eurasia in the last glacial period. The West Beringian group harbors the highest mitogenome diversity and its inferred demography indicates a constantly large effective population size over the Late Pleistocene to Holocene. This suggests that northward forest expansion during recent warming of the Holocene thermal optimum did not affect the gene pool of the collared lemming in West Beringia but reduced genomic diversity and effective population size in all other regions of the Eurasian Arctic. Demographic inference from genomic diversity was corroborated by species distribution modeling showing reduction in species distribution during past climate warming. These conclusions are supported by recent paleoecological evidence suggesting smaller temperature increases and moderate northward forest advances in the extreme northeast of Eurasia during the Late Pleistocene-to-Holocene warming events. This study emphasizes the importance of West Beringia as a potential refugium for cold-adapted Arctic species under ongoing climate warming.


Assuntos
Arvicolinae/genética , Variação Genética/genética , Aquecimento Global/história , Animais , Regiões Árticas , Ásia , Europa (Continente) , Genoma/genética , Genoma Mitocondrial/genética , Genômica , História Antiga , Refúgio de Vida Selvagem , Tundra
6.
Glob Chang Biol ; 26(3): 1908-1925, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31957145

RESUMO

Warming occurs in the Arctic twice as fast as the global average, which in turn leads to a large enhancement in terpenoid emissions from vegetation. Volatile terpenoids are the main class of biogenic volatile organic compounds (VOCs) that play crucial roles in atmospheric chemistry and climate. However, the biochemical mechanisms behind the temperature-dependent increase in VOC emissions from subarctic ecosystems are largely unexplored. Using 13 CO2 -labeling, we studied the origin of VOCs and the carbon (C) allocation under global warming in the soil-plant-atmosphere system of contrasting subarctic heath tundra vegetation communities characterized by dwarf shrubs of the genera Salix or Betula. The projected temperature rise of the subarctic summer by 5°C was realistically simulated in sophisticated climate chambers. VOC emissions strongly depended on the plant species composition of the heath tundra. Warming caused increased VOC emissions and significant changes in the pattern of volatiles toward more reactive hydrocarbons. The 13 C was incorporated to varying degrees in different monoterpene and sesquiterpene isomers. We found that de novo monoterpene biosynthesis contributed to 40%-44% (Salix) and 60%-68% (Betula) of total monoterpene emissions under the current climate, and that warming increased the contribution to 50%-58% (Salix) and 87%-95% (Betula). Analyses of above- and belowground 12/13 C showed shifts of C allocation in the plant-soil systems and negative effects of warming on C sequestration by lowering net ecosystem exchange of CO2 and increasing C loss as VOCs. This comprehensive analysis provides the scientific basis for mechanistically understanding the processes controlling terpenoid emissions, required for modeling VOC emissions from terrestrial ecosystems and predicting the future chemistry of the arctic atmosphere. By changing the chemical composition and loads of VOCs into the atmosphere, the current data indicate that global warming in the Arctic may have implications for regional and global climate and for the delicate tundra ecosystems.


Assuntos
Aquecimento Global , Compostos Orgânicos Voláteis , Regiões Árticas , Ecossistema , Tundra
7.
Ambio ; 49(3): 678-692, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30929249

RESUMO

Changes in Arctic vegetation can have important implications for trophic interactions and ecosystem functioning leading to climate feedbacks. Plot-based vegetation surveys provide detailed insight into vegetation changes at sites around the Arctic and improve our ability to predict the impacts of environmental change on tundra ecosystems. Here, we review studies of changes in plant community composition and phenology from both long-term monitoring and warming experiments in Arctic environments. We find that Arctic plant communities and species are generally sensitive to warming, but trends over a period of time are heterogeneous and complex and do not always mirror expectations based on responses to experimental manipulations. Our findings highlight the need for more geographically widespread, integrated, and comprehensive monitoring efforts that can better resolve the interacting effects of warming and other local and regional ecological factors.


Assuntos
Ecossistema , Tundra , Regiões Árticas , Mudança Climática , Plantas , Estações do Ano
8.
Glob Chang Biol ; 25(12): 4244-4256, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31603617

RESUMO

Arctic shrubification is an observable consequence of climate change, already resulting in ecological shifts and global-scale climate feedbacks including changes in land surface albedo and enhanced evapotranspiration. However, the rate at which shrubs can colonize previously glaciated terrain in a warming world is largely unknown. Reconstructions of past vegetation dynamics in conjunction with climate records can provide critical insights into shrubification rates and controls on plant migration, but paleoenvironmental reconstructions based on pollen may be biased by the influx of exotic pollen to tundra settings. Here, we reconstruct past plant communities using sedimentary ancient DNA (sedaDNA), which has a more local source area than pollen. We additionally reconstruct past temperature variability using bacterial cell membrane lipids (branched glycerol dialkyl glycerol tetraethers) and an aquatic productivity indicator (biogenic silica) to evaluate the relative timing of postglacial ecological and climate changes at a lake on southern Baffin Island, Arctic Canada. The sedaDNA record tightly constrains the colonization of dwarf birch (Betula, a thermophilous shrub) to 5.9 ± 0.1 ka, ~3 ka after local deglaciation as determined by cosmogenic 10 Be moraine dating and >2 ka later than Betula pollen is recorded in nearby lake sediment. We then assess the paleovegetation history within the context of summer temperature and find that paleotemperatures were highest prior to 6.3 ka, followed by cooling in the centuries preceding Betula establishment. Together, these molecular proxies reveal that Betula colonization lagged peak summer temperatures, suggesting that inefficient dispersal, rather than climate, may have limited Arctic shrub migration in this region. In addition, these data suggest that pollen-based climate reconstructions from high latitudes, which rely heavily on the presence and abundance of pollen from thermophilous taxa like Betula, can be compromised by both exotic pollen fluxes and vegetation migration lags.


Assuntos
Lagos , Tundra , Regiões Árticas , Canadá , Mudança Climática
9.
J Microbiol ; 57(10): 865-873, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31571125

RESUMO

Lignocellulose composed of complex carbohydrates and aromatic heteropolymers is one of the principal materials for the production of renewable biofuels. Lignocellulose-degrading genes from cold-adapted bacteria have a potential to increase the productivity of biological treatment of lignocellulose biomass by providing a broad range of treatment temperatures. Antarctic soil metagenomes allow to access novel genes encoding for the cold-active lignocellulose-degrading enzymes, for biotechnological and industrial applications. Here, we investigated the metagenome targeting cold-adapted microbes in Antarctic organic matter-rich soil (KS 2-1) to mine lignolytic and celluloytic enzymes by performing single molecule, real-time metagenomic (SMRT) sequencing. In the assembled Antarctic metagenomic contigs with relative long reads, we found that 162 (1.42%) of total 11,436 genes were annotated as carbohydrate-active enzymes (CAZy). Actinobacteria, the dominant phylum in this soil's metagenome, possessed most of candidates of lignocellulose catabolic genes like glycoside hydrolase families (GH13, GH26, and GH5) and auxiliary activity families (AA7 and AA3). The predicted lignocellulose degradation pathways in Antarctic soil metagenome showed synergistic role of various CAZyme harboring bacterial genera including Streptomyces, Streptosporangium, and Amycolatopsis. From phylogenetic relationships with cellular and environmental enzymes, several genes having potential for participating in overall lignocellulose degradation were also found. The results indicated the presence of lignocellulose-degrading bacteria in Antarctic tundra soil and the potential benefits of the lignocelluolytic enzymes as candidates for cold-active enzymes which will be used for the future biofuel-production industry.


Assuntos
Bactérias/enzimologia , Bactérias/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Lignina/metabolismo , Metagenoma , Microbiologia do Solo , Regiões Antárticas , Bactérias/classificação , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Biocombustíveis/análise , Temperatura Baixa , Filogenia , Solo/química , Tundra
10.
Environ Sci Technol ; 53(21): 12835-12845, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31589028

RESUMO

Arctic-breeding seabirds contain high levels of many anthropogenic contaminants, which they deposit through guano to the tundra near their colonies. Nutrient-rich soil in vicinity to seabird colonies are favorable habitats for soil invertebrates, such as springtails (Collembola), which may result in exposure to seabird-derived contaminants. We quantified a wide range of lipid-soluble and protein-associated environmental contaminants in two springtail species (Megaphorura arctica and Hypogastrura viatica) and their respective habitats (soil/moss) collected underneath seabird cliffs. Although springtails are commonly used in laboratory toxicity tests, this is the first study to measure concentrations of persistent organic pollutants (POPs) and mercury (Hg) in springtails from the field, and to study biotransportation of contaminants by seabirds to soil fauna. We categorized the sites a priori as of low, medium, or high seabird influence, based on the seabird abundance and species composition. This ranking was reflected in increasing δ15N values in soil/moss and springtails with increasing seabird influence. We found clear indications of seabirds impacting the terrestrial soil environments with organic contaminants, and that concentrations were higher in soil and moss close to the bird cliff, compared to farther away. However, we did not find a relationship between contaminant concentration in springtails and the concentrations in soil/moss, or with level of seabird influence. Our study indicates a low uptake of contaminants in the soil fauna, despite seabird-derived contamination of their habitat.


Assuntos
Artrópodes , Solo , Animais , Regiões Árticas , Monitoramento Ambiental , Tundra
11.
Int J Syst Evol Microbiol ; 69(12): 3710-3715, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31665101

RESUMO

A pale-yellow bacterial strain, designated S14-144T, was isolated from tundra soil sampled near the Antarctic Peninsula, South Shetland Islands (62° 22' 34″ S, 59° 42' 34″ W). The cells were strictly aerobic, Gram-stain-positive, non-motile and coccoid-shaped. Growth occurred at 4-28 °C, at pH 5.0-9.0 and in the presence of 0-5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S14-144T formed a lineage within the genus Nakamurella and shared the highest 16S rRNA gene sequence similarity with Nakamurella deserti 12Sc4-1T (96.5 %) and Nakamurella silvestrisS20-107T (96.4 %). The average nucleotide identity value between the genomes of strain 14-144T and the type strain of the species, N. deserti, was 72.0 % . The DNA G+C content of strain S14-144T was 61.6 mol% . The major cellular fatty acids of strain S14-144T were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C16 : 0. The strain contained MK-8(H4) as the predominant respiratory quinone, phosphatidylethanolamine and diphosphatidylglycerol as the major polar lipids, rhamnose, ribose and glucose as the major whole-cell sugars, and meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. On the basis of the phylogenetic, phenotypic and chemotaxonomic analysis, strain S14-144T is considered to represent a novel species of the genus Nakamurella, for which the name Nakamurella antarctica sp. nov. is proposed. The type strain is S14-144T (=CCTCC AB 2015345T=KCTC 39796T).


Assuntos
Actinobacteria/classificação , Filogenia , Microbiologia do Solo , Actinobacteria/isolamento & purificação , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Ilhas , Peptidoglicano/química , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tundra
12.
Environ Sci Process Impacts ; 21(10): 1699-1712, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31549133

RESUMO

To simulate global mercury (Hg) dynamics in chemical transport models (CTMs), surface-atmosphere exchange of gaseous elemental mercury, Hg0, is often parameterized based on resistance-based dry deposition schemes coupled with a re-emission function, mainly from soils. Despite extensive use of this approach, direct evaluations of this implementation against field observations of net Hg0 exchange are lacking. In this study, we evaluate an existing net exchange parameterization (referred to here as the base model) by comparing modeled fluxes of Hg0 to fluxes measured in the field using micrometeorological techniques. Comparisons were performed in two terrestrial ecosystems: a grassland site in Switzerland and an Arctic tundra site in Alaska, U.S., each including summer and winter seasons. The base model included the dry deposition and soil re-emission parameterizations from Zhang et al. (2003) and the global CTM GEOS-Chem, respectively. Comparisons of modeled and measured Hg0 fluxes showed large discrepancies, particularly in the summer months when the base model overestimated daytime net deposition by approximately 9 and 2 ng m-2 h-1 at the grassland and tundra sites, respectively. In addition, the base model was unable to capture a measured nighttime net Hg0 deposition and wintertime deposition. We conducted a series of sensitivity analyses and recommend that Hg simulations using CTMs: (i) reduce stomatal uptake of Hg0 over grassland and tundra in models by a factor 5-7; (ii) increase nighttime net Hg0 deposition, e.g., by increasing ground and cuticular uptake by reducing the respective resistance terms by factors of 3-4 and 2-4, respectively; and (iii) implement a new soil re-emission parameterization to produce larger daytime emissions and lower nighttime emissions. We also compared leaf Hg0 uptake over the growing season estimated by the dry deposition model against foliar Hg measurements, which revealed good agreement with the measured leaf Hg concentrations after adjusting the base model as suggested above. We conclude that the use of resistance-based models combined with the new soil re-emission flux parameterization is able to reproduce observed diel and seasonal patterns of Hg0 exchange in these ecosystems. This approach can be used to improve model parameterizations for other ecosystems if flux measurements become available.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Mercúrio/análise , Solo/química , Poluentes Atmosféricos/química , Alaska , Ecossistema , Monitoramento Ambiental/métodos , Pradaria , Mercúrio/química , Estações do Ano , Suíça , Tundra
13.
J Helminthol ; 94: e87, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31514757

RESUMO

The supralittoral amphipod Traskorchestia ditmari (Derzhavin, 1923) was identified as the intermediate host for Antechiniella septentrionalis Ivanova, Dokuchaev & Spiridonov, 2019, a parasite of the tundra vole Microtus oeconomus and Skrjabinocerca sp. (both Spirurida: Acuariidae) in Magadan Oblast in north-eastern Russia. Joint infection by both larval spirurids was not observed. The infective stage of A. septentrionalis was the encysted larvae, while larvae of Skrjabinocerca sp. were free in the amphipod's coelom. The identity of A. septentrionalis was confirmed using cox1 mtDNA gene analysis, performed on adult stages from a tundra vole and on larvae from amphipods. Possible transmission routes of A. septentrionalis are discussed.


Assuntos
Anfípodes/parasitologia , Arvicolinae/parasitologia , Infecções por Spirurida/veterinária , Espirurídios/fisiologia , Animais , Feminino , Larva , Masculino , Federação Russa , Espirurídios/crescimento & desenvolvimento , Tundra
14.
Oecologia ; 191(3): 601-608, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31522244

RESUMO

The functional composition of plant communities is a critical modulator of climate change impacts on ecosystems, but it is not a simple function of regional climate. In the Arctic tundra, where climate change is proceeding the most rapidly, communities have not shifted their trait composition as predicted by spatial temperature-trait relationships. Important causal pathways are thus missing from models of trait composition change. Here, we study causes of plant community functional variation in an oroarctic tundra landscape in Kilpisjärvi, Finland. We consider the community-weighted means of plant vegetative height, as well as two traits related to the leaf economic spectrum. Specifically, we model their responses to locally measured summer air temperature, snow conditions, and soil resource levels. For each of the traits, we also quantify the importance of intraspecific trait variation (ITV) for between-community functional differences and trait-environment matching. Our study shows that in a tundra landscape (1) snow is the most influential abiotic variable affecting functional composition, (2) vegetation height is under weak local environmental control, whereas leaf economics is under strong local environmental control, (3) the relative magnitude of ITV differs between traits, and (4) ITV is not very consequential for community-level trait-environment relationships. Our analyses highlight the importance of winter conditions for community functional composition in seasonal areas. We show that winter climate change can either amplify or counter the effects summer warming, depending on the trait.


Assuntos
Ecossistema , Neve , Finlândia , Plantas , Tundra
15.
Sci Total Environ ; 694: 133684, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31398651

RESUMO

Paleolimnology uses sedimentary biomarkers as proxies to reconstruct long-term changes in environmental conditions from lake sediment cores. This work describes an untargeted metabolomics-based approach and uniquely applies it to the field of paleolimnology to identify novel sediment biomarkers to track long-term patterns in treeline dynamics. We identified new potential biomarkers across the Canadian northern Arctic, non-alpine, treeline using high-resolution accurate mass spectrometry, and pattern recognition analysis. This method was applied to 120 sediment core extracts from 14 boreal, 25 forest-tundra, and 21 tundra lakes to assess long-term fluctuations in treeline position. High resolution accurate mass spectrometry resolved many compounds from complex mixtures with low mass accuracy errors. This generated a large dataset that required metabolomics styled statistical analyses to identify potential biomarkers. In total, 29 potential biomarkers discriminated between boreal and tundra lakes. Tetrapyrrole-type phorbides and squalene derivatives dominated in boreal regions, while biohopane-type lipids were in the tundra regions. Tetrapyrroles were in both surface and subsurface sediments of boreal lakes indicating these compounds can survive long-term burial in sediments. At the ecozone level, tetrapyrroles were more abundant in boreal Taiga Shield, and Taiga Plains. Boreal plant extracts belonging to Pinaceae and Ericaceae also contained tetrapyrroles. Squalene derivatives demonstrated long-term preservation, but wider distribution than tetrapyrroles. Hopanoids were present in tundra and forest-tundra lake regions, specifically the Low Arctic and Taiga Shield, and were absent in all boreal lake sediments. Herein, we describe a method that can systematically identify new paleolimnological biomarkers. Novel biomarkers would facilitate multi-proxy paleolimnological studies and potentially lead to more accurate paleoenvironmental reconstructions.


Assuntos
Biomarcadores Ambientais , Monitoramento Ambiental , Regiões Árticas , Canadá , Sedimentos Geológicos/química , Lagos/química , Taiga , Tundra
16.
Int J Syst Evol Microbiol ; 69(11): 3437-3442, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31385781

RESUMO

A Gram-stain-negative, non-motile, aerobic, short rod-shaped bacterium, designated OD32T, was isolated from a soil sample taken from the rhizosphere of Silene acaulis collected from the Arctic tundra. The novel strain, OD32T, was able to grow at 15-37 °C (optimum, 33 °C), pH 6.5-9.5 (pH 7.5-8.0) and 0-0.5 % NaCl (0 %, w/v). A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain OD32T was most closely related to the genus Deinococcus; it shared the highest sequence similarity (95.7 %) with Deinococcus grandis ATCC 43672T. Genomic DNA G+C content of the strain OD32T was 68.2 mol%. The predominant respiratory quinone was menaquinone 8 (MK-8). The major fatty acids were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C15 : 1 ω6c, C17 : 1 ω6c, C17 : 0, C16 : 0 and iso-C17 : 0. Based on phylogenetic inference and genotypic characteristics, strain OD32T represents a novel species of the genus Deinococcus, for which the name Deinococcus arcticus sp. nov. is proposed. The type strain is OD32T (=KCTC 33972T=CICC 24671T).


Assuntos
Deinococcus/classificação , Filogenia , Rizosfera , Silene/microbiologia , Microbiologia do Solo , Tundra , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Deinococcus/isolamento & purificação , Ácidos Graxos/química , Genótipo , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Svalbard
17.
Int J Syst Evol Microbiol ; 69(12): 3745-3750, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31433290

RESUMO

In the present paper, we describe a new species of the genus Flavobacterium, designated as strain 1E403T, which was isolated from a soil sample collected from the Arctic. Strain 1E403T was Gram-stain-negative, yellow-pigmented, rod-shaped, gliding and aerobic. Growth occurred at 4-37 °C (optimum, 28 °C), pH 6.0-9.0 (pH 7.0) and with 0-2 % (w/v) NaCl (0 %) on modified marine agar 2216. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that strain 1E403T was affiliated with the genus Flavobacterium and was more closely related to Flavobacterium subsaxonicum DSM 21790T (96.6 %) than to other species. In silico genomic comparisons, including average nucleotide identity and the digital DNA-DNA hybridization values, showed 73.9 % and 18.8 % identity to the closest relative Flavobacterium subsaxonicum DSM 21790T, respectively. The average amino acid identity value between strain 1E403T and Flavobacterium aquatile DSM 1132T was 63.8 %. The DNA G+C content of the strain was 36.8 %, while the sole respiratory quinone was menaquinone-6. Iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) were the major fatty acids (>10 %) of strain 1E403T. The polar lipid profile of strain 1E403T contained phosphatidylethanolamine, four unidentified aminolipids and two unidentified phospholipids. Based on the phenotypic characteristics, chemotaxonomic characteristics and phylogenetic inference, strain 1E403T represents a novel species of the genus Flavobacterium, and we propose the name Flavobacterium cerinum sp. nov. The type strain of Flavobacterium cerinum sp. nov. is 1E403T (=KCTC 62960T=MCCC 1H00356T).


Assuntos
Flavobacterium/classificação , Filogenia , Microbiologia do Solo , Tundra , Regiões Árticas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacterium/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
18.
PLoS One ; 14(7): e0216966, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291259

RESUMO

Larix populations at the tundra-taiga ecotone in northern Siberia are highly under-represented in population genetic studies, possibly due to the remoteness of these regions that can only be accessed at extraordinary expense. The genetic signatures of populations in these boundary regions are therefore largely unknown. We aim to generate organelle reference genomes for the detection of single nucleotide polymorphisms (SNPs) that can be used for paleogenetic studies. We present 19 complete chloroplast genomes and mitochondrial genomic sequences of larches from the southern lowlands of the Taymyr Peninsula (northernmost range of Larix gmelinii (Rupr.) Kuzen.), the lower Omoloy River, and the lower Kolyma River (both in the range of Larix cajanderi Mayr). The genomic data reveal 84 chloroplast SNPs and 213 putatively mitochondrial SNPs. Parsimony-based chloroplast haplotype networks show no spatial structure of individuals from different geographic origins, while the mitochondrial haplotype network shows at least a slight spatial structure with haplotypes from the Omoloy and Kolyma populations being more closely related to each other than to most of the haplotypes from the Taymyr populations. Whole genome alignments with publicly available complete chloroplast genomes of different Larix species show that among official plant barcodes only the rcbL gene contains sufficient polymorphisms, but has to be sequenced completely to distinguish the different provenances. We provide 8 novel mitochondrial SNPs that are putatively diagnostic for the separation of L. gmelinii and L. cajanderi, while 4 chloroplast SNPs have the potential to distinguish the L. gmelinii/L. cajanderi group from other Larix species. Our organelle references can be used for a targeted primer and probe design allowing the generation of short amplicons. This is particularly important with regard to future investigations of, for example, the biogeographic history of Larix by screening ancient sedimentary DNA of Larix.


Assuntos
Larix/genética , Mapeamento Cromossômico , DNA Antigo , DNA de Cloroplastos/genética , DNA Mitocondrial/genética , DNA de Plantas/genética , Variação Genética , Genética Populacional , Genoma de Cloroplastos , Genoma Mitocondrial , Genoma de Planta , Haplótipos , História Antiga , Larix/classificação , Polimorfismo de Nucleotídeo Único , Sibéria , Taiga , Tundra
19.
Nat Plants ; 5(6): 568-574, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31182843

RESUMO

Plant-emitted volatile organic compounds (VOCs) play fundamental roles in atmospheric chemistry and ecological processes by contributing to aerosol formation1 and mediating species interactions2. Rising temperatures and the associated shifts in vegetation composition have been shown to be the primary drivers of plant VOC emissions in Arctic ecosystems3. Although herbivorous insects also strongly alter plant VOC emissions2, no studies have addressed the impact of herbivory on plant VOC emissions in the Arctic. Here we show that warming dramatically increases the amount, and alters the blend, of VOCs released in response to herbivory. We observed that a tundra ecosystem subjected to warming, by open-top chambers, for 8 or 18 years showed a fourfold increase in leaf area eaten by insect herbivores. Herbivory by autumnal moth (Epirrita autumnata) larvae, and herbivory-mimicking methyl jasmonate application, on the widespread circumpolar dwarf birch (Betula nana) both substantially increased emissions of terpenoids. The long-term warming treatments and mimicked herbivory caused, on average, a two- and fourfold increase in monoterpene emissions, respectively. When combined, emissions increased 11-fold, revealing a strong synergy between warming and herbivory. The synergistic effect was even more pronounced for homoterpene emissions. These findings suggest that, in the rapidly warming Arctic, insect herbivory may be a primary determinant of VOC emissions during periods of active herbivore feeding.


Assuntos
Betula/parasitologia , Aquecimento Global , Herbivoria , Insetos/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Animais , Betula/imunologia , Ecossistema , Tundra
20.
Int J Syst Evol Microbiol ; 69(7): 1926-1933, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31157612

RESUMO

A novel bacterial strain, JDX94T, was isolated from tundra soil sampled north of the Yellow River station, Arctic. Cells were Gram-stain-negative, non-spore-forming, short rod-shaped and aerobic. The strain displayed growth at 4-37 °C with an optimum at 28 °C, with 0-1.0 % (w/v) NaCl (optimum, 0%) and at pH 6.0-9.0 (optimum, pH 7.0-7.5). Cells contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 and iso-C17 : 0 3-OH as its major cellular fatty acids and menaquinone-7 as the only respiratory quinone. The polar lipid profile of strain JDX94T consisted of phosphatidylethanolamine, two unidentified aminolipids and four unknown polar lipids. The DNA G+C content was 37.5 mol%. On the basis 16S rRNA gene sequence comparison, strain JDX94T showed the highest sequence similarity (96.7 %) to Pedobacteragri JCM 15120T, followed by Pedobacteralluvionis DSM 19624T (96.3 %). Furthermore, the average nucleotide identity and digital DNA-DNA hybridization values between strain JDX94T and related species of the genus Pedobacter were 74.6-79.2 % and 18.9-24.5 %, respectively. Based on the presented results, we propose a novel species for which the name Pedobacterchinensis sp. nov. is suggested, with the type strain JDX94T (=MCCC 1H00335T= KCTC 62850T).


Assuntos
Celulose/metabolismo , Pedobacter/classificação , Filogenia , Microbiologia do Solo , Tundra , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Pedobacter/isolamento & purificação , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Svalbard , Vitamina K 2/análogos & derivados , Vitamina K 2/química
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