Dataset Information

Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord.

ABSTRACT: Kongsfjorden is a glacial fjord in the Arctic that is influenced by both Atlantic and Arctic water masses. In the present report retrievable heterotrophic bacteria isolated from two distinct zones (outer and inner fjord) of Kongsfjorden was studied during summer to fall of 2012. 16S rRNA gene sequences of the retrievable heterotrophic bacteria corresponded to γ-proteobacteria (13 phylotypes), α-proteobacteria (3 phylotypes), Bacteroidetes (4 phylotypes) and Actinobacteria (2 phylotypes). The heterotrophic bacterial community structure was fundamentally different in different months which could be linked to changes in the water masses and/or phytoplankton bloom dynamics. It is hypothesized that monitoring the retrievable heterotrophic bacterial assemblage in the fjord would give valuable insights into the complex ecological role they play under extreme and dynamic conditions.

SUBMITTER: Sinha RK

PROVIDER: S-EPMC5243246 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord.

Sinha Rupesh Kumar RK Krishnan K P KP Kerkar Savita S Divya David T T

Indian journal of microbiology 20160922 1

Kongsfjorden is a glacial fjord in the Arctic that is influenced by both Atlantic and Arctic water masses. In the present report retrievable heterotrophic bacteria isolated from two distinct zones (outer and inner fjord) of Kongsfjorden was studied during summer to fall of 2012. 16S rRNA gene sequences of the retrievable heterotrophic bacteria corresponded to γ-proteobacteria (13 phylotypes), α-proteobacteria (3 phylotypes), Bacteroidetes (4 phylotypes) and ...[more]

PMID: 28148988

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Project description:Fjords and continental shelves represent distinct marine ecosystems in the pan-arctic region. Kongsfjorden is a glacial fjord that is located on the west coast of Svalbard, and is influenced by both Atlantic and Arctic water masses. The Bering Sea consists of a huge continental shelf in the northeast and a deep ocean basin in the southwest, and is influenced by Pacific water. Microbial community compositions of Arctic sediment samples BJ4 from outer basin and BJ36 from inner basin of Kongsfjorden and sub-Arctic samples NEC5 from shallow shelf and DBS1 from deep basin region of the northern Bering Sea were investigated using 454 pyrosequencing of archaeal and bacterial 16S rRNA genes. Most archaeal sequences in the sediments were related to Thaumarchaeota, though Euryarchaeota were more abundant in the Arctic glacier-influencing inner basin sediment BJ36. Thaumarchaeota Group C3 was the dominant archaeal population in all samples. Proteobacteria and Bacteroidetes dominated the sediment bacterial communities. Acidobacteria and Actinobacteria were also dominant in the northern Bering Sea samples. Alphaproteobacteria and Epsilonproteobacteria were the two main classes in Kongsfjorden sediment bacterial communities while Deltaproteobacteria and Gammaproteobacteria were dominant in the northern Bering Sea sediments. Differences in the presence and abundance of other dominant archaeal and bacterial populations were observed among sediment samples. In contrast to archaeal community differences that the Arctic BJ36 archaeal community was distinct from the sub-Arctic sediments and the Arctic outer basin sediment BJ4, cluster analysis based on bacterial OTU (operational taxonomic unit) distributions indicated that the Arctic and sub-Arctic bacterial communities segregated from one another. These results suggest that the sediment archaeal and bacterial community compositions can be driven by different environmental factors. Differences in the presence and abundance of particular archaeal species (e.g., Candidatus Nitrosopumilus and Methanococcoides) or bacterial species (e.g., Sulfurimonas, Sulfurovum, and Desulfobulbaceae) involved in biogeochemical cycles were also observed among sediment samples. At the same time, despite the community variation, some phylotypes (e.g., Marinicella) were dominant in all sediments. This study indicates diverse microbial communities inhabiting pan-arctic marine sediments, and highlights potential roles for Archaea and Bacteria in global biogeochemical cycles in these environments.

Project description:Understanding individual-level variation in response to the environment is fundamental to understanding life-history evolution and population dynamics. Telomeres, the protective caps at the ends of chromosomes, shorten in response to oxidative stress, and telomere shortening is correlated with reduced survival and life span. Investigating telomere dynamics may help us quantify individual variation in the costs experienced from social and ecological factors, and enhance our understanding of the dynamics of natural populations. Here, we study spatio-temporal variation in lifelong telomere dynamics in the Seychelles warbler, Acrocephalus sechellensis. We combine long-term life history and ecological data with a large longitudinal dataset of mean telomere lengths, consisting of 1,808 samples from 22 cohorts born between 1993 and 2014. We provide a detailed analysis of how telomere dynamics vary over individual life spans and cohorts, and with spatio-temporal variation in the social and ecological environment. We found that telomere length decreases with cross-sectional and longitudinal measures of age, and most rapidly very early in life. However, both cross-sectional and longitudinal data suggested that against this overall pattern of shortening, bouts of telomere length increase occur in some individuals. Using a large number of repeated measurements we show statistically that these increases are unlikely to be explained solely by qPCR measurement error. Telomere length varied markedly among cohorts. Telomere length was positively associated with temporal variation in island-wide insect abundance-a key resource for the insectivorous Seychelles warbler-suggesting that the costs associated with living in harsher environments can be studied by investigating telomere dynamics. We also found evidence for sex-specific relationships between telomeres and tarsus length, potentially reflecting differential costs of growth. Our long-term data show that in a natural population, telomere dynamics vary in a complex manner over individual life spans, and across space and time. Variance in telomere dynamics among individuals is the product of a wide array of genetic, parental and environmental factors. Explaining this variation more fully will require the integration of comprehensive long-term ecological and genetic data from multiple populations and species.

Dataset Information

Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord.

Publications

Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord.

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