Skip header and navigation

3 records – page 1 of 1.

Distinctive microbial communities in subzero hypersaline brines from Arctic coastal sea ice and rarely sampled cryopegs.

https://arctichealth.org/en/permalink/ahliterature308589
Source
FEMS Microbiol Ecol. 2019 12 01; 95(12):
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
12-01-2019
Author
Zachary S Cooper
Josephine Z Rapp
Shelly D Carpenter
Go Iwahana
Hajo Eicken
Jody W Deming
Author Affiliation
School of Oceanography, University of Washington, P.O. Box 357940 Seattle, WA 98195, USA.
Source
FEMS Microbiol Ecol. 2019 12 01; 95(12):
Date
12-01-2019
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Alaska
Arctic Regions
Bacteria - classification - genetics - isolation & purification
Cold Temperature
Ice Cover - microbiology
Microbiota
Permafrost - microbiology
Phylogeny
RNA, Ribosomal, 16S - genetics
Salinity
Salts
Seawater - microbiology
Temperature
Abstract
Hypersaline aqueous environments at subzero temperatures are known to be inhabited by microorganisms, yet information on community structure in subzero brines is very limited. Near Utqiagvik, Alaska, we sampled subzero brines (-6°C, 115-140 ppt) from cryopegs, i.e. unfrozen sediments within permafrost that contain relic (late Pleistocene) seawater brine, as well as nearby sea-ice brines to examine microbial community composition and diversity using 16S rRNA gene amplicon sequencing. We also quantified the communities microscopically and assessed environmental parameters as possible determinants of community structure. The cryopeg brines harbored surprisingly dense bacterial communities (up to 108 cells mL-1) and millimolar levels of dissolved and particulate organic matter, extracellular polysaccharides and ammonia. Community composition and diversity differed between the two brine environments by alpha- and beta-diversity indices, with cryopeg brine communities appearing less diverse and dominated by one strain of the genus Marinobacter, also detected in other cold, hypersaline environments, including sea ice. The higher density and trend toward lower diversity in the cryopeg communities suggest that long-term stability and other features of a subzero brine are more important selective forces than in situ temperature or salinity, even when the latter are extreme.
PubMed ID
31626297 View in PubMed
Less detail

Future projection of greenhouse gas emissions due to permafrost degradation using a simple numerical scheme with a global land surface model.

https://arctichealth.org/en/permalink/ahliterature304451
Source
Prog Earth Planet Sci. 2020; 7(1):56
Publication Type
Journal Article
Date
2020
Author
Tokuta Yokohata
Kazuyuki Saito
Akihiko Ito
Hiroshi Ohno
Katsumasa Tanaka
Tomohiro Hajima
Go Iwahana
Author Affiliation
Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan.
Source
Prog Earth Planet Sci. 2020; 7(1):56
Date
2020
Language
English
Publication Type
Journal Article
Abstract
The Yedoma layer, a permafrost layer containing a massive amount of underground ice in the Arctic regions, is reported to be rapidly thawing. In this study, we develop the Permafrost Degradation and Greenhouse gasses Emission Model (PDGEM), which describes the thawing of the Arctic permafrost including the Yedoma layer due to climate change and the greenhouse gas (GHG) emissions. The PDGEM includes the processes by which high-concentration GHGs (CO2 and CH4) contained in the pores of the Yedoma layer are released directly by dynamic degradation, as well as the processes by which GHGs are released by the decomposition of organic matter in the Yedoma layer and other permafrost. Our model simulations show that the total GHG emissions from permafrost degradation in the RCP8.5 scenario was estimated to be 31-63 PgC for CO2 and 1261-2821 TgCH4 for CH4 (68th percentile of the perturbed model simulations, corresponding to a global average surface air temperature change of 0.05-0.11 °C), and 14-28 PgC for CO2 and 618-1341 TgCH4 for CH4 (0.03-0.07 °C) in the RCP2.6 scenario. GHG emissions resulting from the dynamic degradation of the Yedoma layer were estimated to be less than 1% of the total emissions from the permafrost in both scenarios, possibly because of the small area ratio of the Yedoma layer. An advantage of PDGEM is that geographical distributions of GHG emissions can be estimated by combining a state-of-the-art land surface model featuring detailed physical processes with a GHG release model using a simple scheme, enabling us to consider a broad range of uncertainty regarding model parameters. In regions with large GHG emissions due to permafrost thawing, it may be possible to help reduce GHG emissions by taking measures such as restraining land development.
PubMed ID
33088673 View in PubMed
Less detail

Permafrost ice caves: an unrecognized microhabitat for Arctic wildlife.

https://arctichealth.org/en/permalink/ahliterature303863
Source
Ecology. 2020 Dec 22; :e03276
Publication Type
Journal Article
Date
Dec-22-2020
Author
Thomas W Glass
Greg A Breed
Go Iwahana
Matthew C Kynoch
Martin D Robards
Cory T Williams
Knut Kielland
Author Affiliation
Wildlife Conservation Society, 3550 Airport Way Suite 5, Fairbanks, Alaska, 99709, USA.
Source
Ecology. 2020 Dec 22; :e03276
Date
Dec-22-2020
Language
English
Publication Type
Journal Article
PubMed ID
33351185 View in PubMed
Less detail