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Arctic permafrost active layer detachments stimulate microbial activity and degradation of soil organic matter.

https://arctichealth.org/en/permalink/ahliterature97020
Source
Environ Sci Technol. 2010 Jun 1;44(11):4076-82
Publication Type
Article
Date
Jun-1-2010
Author
Brent G Pautler
André J Simpson
David J McNally
Scott F Lamoureux
Myrna J Simpson
Author Affiliation
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
Source
Environ Sci Technol. 2010 Jun 1;44(11):4076-82
Date
Jun-1-2010
Language
English
Publication Type
Article
Keywords
Arctic Regions
Bacteria - metabolism
Fatty Acids - metabolism
Magnetic Resonance Spectroscopy
Nunavut
Soil Microbiology
Abstract
Large quantities of soil organic carbon in Arctic permafrost zones are becoming increasingly unstable due to a warming climate. High temperatures and substantial rainfall in July 2007 in the Canadian High Arctic resulted in permafrost active layer detachments (ALDs) that redistributed soils throughout a small watershed in Nunavut, Canada. Molecular biomarkers and NMR spectroscopy were used to measure how ALDs may lead to microbial activity and decomposition of previously unavailable soil organic matter (SOM). Increased concentrations of extracted bacterial phospholipid fatty acids (PLFAs) and large contributions from bacterial protein/peptides in the NMR spectra at recent ALDs suggest increased microbial activity. PLFAs were appreciably depleted in a soil sample where ALDs occurred prior to 2003. However an enrichment of bacterial derived peptidoglycan was observed by (1)H-(13)C heteronuclear multiple quantum coherence (HMQC) and (1)H diffusion edited (DE) NMR and enhanced SOM degradation was observed by (13)C solid-state NMR. These data suggest that a previous rise in microbial activity, as is currently underway at the recent ALD site, led to degradation and depletion of labile SOM components. Therefore, this study indicates that ALDs may amplify climate change due to the release of labile SOM substrates from thawing High Arctic permafrost.
PubMed ID
20459054 View in PubMed
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Broad-scale lake expansion and flooding inundates essential wood bison habitat.

https://arctichealth.org/en/permalink/ahliterature295933
Source
Nat Commun. 2017 02 23; 8:14510
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
02-23-2017
Author
Jennifer B Korosi
Joshua R Thienpont
Michael F J Pisaric
Peter deMontigny
Joelle T Perreault
Jamylynn McDonald
Myrna J Simpson
Terry Armstrong
Steven V Kokelj
John P Smol
Jules M Blais
Author Affiliation
Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N6N5.
Source
Nat Commun. 2017 02 23; 8:14510
Date
02-23-2017
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Bison - physiology
Climate
Conservation of Natural Resources
Ecosystem
Floods
Geography
Geologic sediments
Lakes
Lignin - chemistry
Northwest Territories
Phenols - chemistry
Abstract
Understanding the interaction between the response of a complex ecosystem to climate change and the protection of vulnerable wildlife species is essential for conservation efforts. In the Northwest Territories (Canada), the recent movement of the Mackenzie wood bison herd (Bison bison athabascae) out of their designated territory has been postulated as a response to the loss of essential habitat following regional lake expansion. We show that the proportion of this landscape occupied by water doubled since 1986 and the timing of lake expansion corresponds to bison movements out of the Mackenzie Bison Sanctuary. Historical reconstructions using proxy data in dated sediment cores show that the scale of recent lake expansion is unmatched over at least the last several hundred years. We conclude that recent lake expansion represents a fundamental alteration of the structure and function of this ecosystem and its use by Mackenzie wood bison, in response to climate change.
Notes
Cites: Proc Natl Acad Sci U S A. 2015 Sep 22;112(38):11789-94 PMID 26351688
Cites: Can J Vet Res. 1993 Oct;57(4):231-5 PMID 8269360
Cites: Proc Natl Acad Sci U S A. 2007 Jul 24;104(30):12395-7 PMID 17606917
Cites: Conserv Biol. 2009 Oct;23(5):1080-9 PMID 19549219
Cites: Science. 2005 Jun 3;308(5727):1429 PMID 15933192
PubMed ID
28230049 View in PubMed
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Broad-scale lake expansion and flooding inundates essential wood bison habitat.

https://arctichealth.org/en/permalink/ahliterature280321
Source
Nat Commun. 2017 Feb 23;8:14510
Publication Type
Article
Date
Feb-23-2017
Author
Jennifer B Korosi
Joshua R Thienpont
Michael F J Pisaric
Peter deMontigny
Joelle T Perreault
Jamylynn McDonald
Myrna J Simpson
Terry Armstrong
Steven V Kokelj
John P Smol
Jules M Blais
Source
Nat Commun. 2017 Feb 23;8:14510
Date
Feb-23-2017
Language
English
Publication Type
Article
Abstract
Understanding the interaction between the response of a complex ecosystem to climate change and the protection of vulnerable wildlife species is essential for conservation efforts. In the Northwest Territories (Canada), the recent movement of the Mackenzie wood bison herd (Bison bison athabascae) out of their designated territory has been postulated as a response to the loss of essential habitat following regional lake expansion. We show that the proportion of this landscape occupied by water doubled since 1986 and the timing of lake expansion corresponds to bison movements out of the Mackenzie Bison Sanctuary. Historical reconstructions using proxy data in dated sediment cores show that the scale of recent lake expansion is unmatched over at least the last several hundred years. We conclude that recent lake expansion represents a fundamental alteration of the structure and function of this ecosystem and its use by Mackenzie wood bison, in response to climate change.
PubMed ID
28230049 View in PubMed
Less detail

Differences in Riverine and Pond Water Dissolved Organic Matter Composition and Sources in Canadian High Arctic Watersheds Affected by Active Layer Detachments.

https://arctichealth.org/en/permalink/ahliterature287995
Source
Environ Sci Technol. 2018 Feb 06;52(3):1062-1071
Publication Type
Article
Date
Feb-06-2018
Author
Jun-Jian Wang
Melissa J Lafrenière
Scott F Lamoureux
André J Simpson
Yves Gélinas
Myrna J Simpson
Source
Environ Sci Technol. 2018 Feb 06;52(3):1062-1071
Date
Feb-06-2018
Language
English
Publication Type
Article
Abstract
Regional warming has caused permafrost thermokarst and disturbances, such as active layer detachments (ALDs), which may alter carbon feedback in Arctic ecosystems. However, it is currently unclear how these disturbances alter DOM biogeochemistry in rivers and ponds in Arctic ecosystems. Water samples from the main river channel, ALD-disturbed/undisturbed tributaries, and disturbed/undisturbed ponds within a catchment in the Canadian High Arctic were collected and analyzed using carbon isotopes and spectroscopic methods. Both river and pond samples had large variations in dissolved organic carbon (DOC) concentrations. Ponds, particularly ALD-disturbed ponds, had much older 14C DOC ages than rivers. Results from d13C and absorption and fluorescence analyses indicate higher autochthonous contributions in ponds than rivers and increasing autochthonous contributions from upper to lower reaches of the main channel. The disturbed samples had less carbohydrates but more carboxyl-rich alicyclic molecules in 1H nuclear magnetic resonance spectra than undisturbed samples. These ALD-impacted samples also contained less terrestrial-humic-like but more oxidized-quinone-like components in the fluorescence spectra. Interestingly, the disturbed pond DOM displayed the greatest DOM oxidation with ALDs compared to undisturbed areas. Compared to Arctic rivers, small Arctic ponds have DOM predominantly from permafrost and microbial sources and may have a disproportionally stronger positive feedback on climate warming.
PubMed ID
29301070 View in PubMed
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Molecular-level methods for monitoring soil organic matter responses to global climate change.

https://arctichealth.org/en/permalink/ahliterature101780
Source
J Environ Monit. 2011 May;13(5):1246-54
Publication Type
Article
Date
May-2011
Author
Xiaojuan Feng
Myrna J Simpson
Author Affiliation
Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario M1C 1A4, Canada. xfeng@erdw.ethz.ch
Source
J Environ Monit. 2011 May;13(5):1246-54
Date
May-2011
Language
English
Publication Type
Article
Keywords
Air Pollutants - analysis
Atmosphere - chemistry
Carbon Dioxide - analysis
Climate change
Environmental Monitoring - methods
Magnetic Resonance Spectroscopy
Nitrogen - analysis
Organic Chemicals - chemistry
Soil - analysis - chemistry
Temperature
Abstract
Soil organic matter (SOM) is one of the most complex natural mixtures on earth. It plays a critical role in many ecosystem functions and is directly responsible for sustaining life on our planet. However, due to its chemical heterogeneity, SOM composition at molecular-level is still not completely clear. Consequently, the response of SOM to global climate change is difficult to predict. Here we highlight applications of two complementary molecular-level methods (biomarkers and nuclear magnetic resonance (NMR)) for ascertaining SOM responses to various environmental changes. Biomarker methods that measure highly specific molecules determine the source and decomposition stage of SOM components. However, biomarkers only make up a small fraction of SOM components because much of SOM is non-extractable. By comparison, (13)C solid-state NMR allows measurement of SOM in its entirety with little or no pretreatment but suffers from poor resolution (due to overlapping of SOM components) and insensitivity, and thus subtle changes in SOM composition may not always be detected. Alternatively, (1)H solution-state NMR methods offer an added benefit of improved resolution and sensitivity but can only analyze SOM components that are fully soluble (humic type molecules) in an NMR compatible solvent. We discuss how these complementary methods have been employed to monitor SOM responses to: soil warming in a temperate forest, elevated atmospheric CO(2) and nitrogen fertilization in a temperate forest, and permafrost thawing in the Canadian High Arctic. These molecular-level methods allow some novel and important observations of soil dynamics and ecosystem function in a changing climate.
PubMed ID
21416081 View in PubMed
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