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Late Holocene climatic variability in Subarctic Canada: Insights from a high-resolution lake record from the central Northwest Territories.

https://arctichealth.org/en/permalink/ahliterature292541
Source
PLoS One. 2018; 13(6):e0199872
Publication Type
Journal Article
Date
2018
Author
April S Dalton
R Timothy Patterson
Helen M Roe
Andrew L Macumber
Graeme T Swindles
Jennifer M Galloway
Jesse C Vermaire
Carley A Crann
Hendrik Falck
Author Affiliation
Ottawa-Carleton Geoscience Centre and Department of Earth Sciences, Carleton University, Ottawa, Canada.
Source
PLoS One. 2018; 13(6):e0199872
Date
2018
Language
English
Publication Type
Journal Article
Abstract
We examined late Holocene (ca. 3300 yr BP to present-day) climate variability in the central Northwest Territories (Canadian Subarctic) using a diatom and sedimentological record from Danny's Lake (63.48ºN, 112.54ºW), located 40 km southwest of the modern-day treeline. High-resolution sampling paired with a robust age model (25 radiocarbon dates) allowed for the examination of both lake hydroecological conditions (30-year intervals; diatoms) and sedimentological changes in the watershed (12-year intervals; grain size records) over the late Holocene. Time series analysis of key lake ecological indicators (diatom species Aulacoseira alpigena, Pseudostaurosira brevistriata and Achnanthidium minutissimum) and sedimentological parameters, reflective of catchment processes (coarse silt fraction), suggests significant intermittent variations in turbidity, pH and light penetration within the lake basin. In the diatom record, we observed discontinuous periodicities in the range of ca. 69, 88-100, 115-132, 141-188, 562, 750 and 900 years (>90% and >95% confidence intervals), whereas the coarse silt fraction was characterized by periodicities in the >901 and 95% confidence interval). Periodicities in the proxy data from the Danny's Lake sediment core align with changes in total solar irradiance over the past ca. 3300 yr BP and we hypothesize a link to the Suess Cycle, Gleissberg Cycle and Pacific Decadal Oscillation via occasional inland propagation of shifting air masses over the Pacific Ocean. This research represents an important baseline study of the underlying causes of climate variability in the Canadian Subarctic and provides details on the long-term climate variability that has persisted in this region through the past three thousand years.
Notes
Cites: Biol Rev Camb Philos Soc. 2015 May;90(2):522-41 PMID 24917134
Cites: Proc Natl Acad Sci U S A. 2005 Mar 22;102(12):4397-402 PMID 15738395
Cites: Ann Rev Mar Sci. 2010;2:115-43 PMID 21141660
Cites: Proc Natl Acad Sci U S A. 2004 Mar 23;101(12):4136-41 PMID 15016919
Cites: Sci Rep. 2014 Jan 09;4:3611 PMID 24402348
PubMed ID
29953559 View in PubMed
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Late Holocene climatic variability in Subarctic Canada: Insights from a high-resolution lake record from the central Northwest Territories.

https://arctichealth.org/en/permalink/ahliterature296859
Source
PLoS One. 2018; 13(6):e0199872
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
2018
Author
April S Dalton
R Timothy Patterson
Helen M Roe
Andrew L Macumber
Graeme T Swindles
Jennifer M Galloway
Jesse C Vermaire
Carley A Crann
Hendrik Falck
Author Affiliation
Ottawa-Carleton Geoscience Centre and Department of Earth Sciences, Carleton University, Ottawa, Canada.
Source
PLoS One. 2018; 13(6):e0199872
Date
2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Canada
Climate change
Diatoms
Fossils
Lakes
Abstract
We examined late Holocene (ca. 3300 yr BP to present-day) climate variability in the central Northwest Territories (Canadian Subarctic) using a diatom and sedimentological record from Danny's Lake (63.48ºN, 112.54ºW), located 40 km southwest of the modern-day treeline. High-resolution sampling paired with a robust age model (25 radiocarbon dates) allowed for the examination of both lake hydroecological conditions (30-year intervals; diatoms) and sedimentological changes in the watershed (12-year intervals; grain size records) over the late Holocene. Time series analysis of key lake ecological indicators (diatom species Aulacoseira alpigena, Pseudostaurosira brevistriata and Achnanthidium minutissimum) and sedimentological parameters, reflective of catchment processes (coarse silt fraction), suggests significant intermittent variations in turbidity, pH and light penetration within the lake basin. In the diatom record, we observed discontinuous periodicities in the range of ca. 69, 88-100, 115-132, 141-188, 562, 750 and 900 years (>90% and >95% confidence intervals), whereas the coarse silt fraction was characterized by periodicities in the >901 and 95% confidence interval). Periodicities in the proxy data from the Danny's Lake sediment core align with changes in total solar irradiance over the past ca. 3300 yr BP and we hypothesize a link to the Suess Cycle, Gleissberg Cycle and Pacific Decadal Oscillation via occasional inland propagation of shifting air masses over the Pacific Ocean. This research represents an important baseline study of the underlying causes of climate variability in the Canadian Subarctic and provides details on the long-term climate variability that has persisted in this region through the past three thousand years.
PubMed ID
29953559 View in PubMed
Less detail

The long-term fate of permafrost peatlands under rapid climate warming.

https://arctichealth.org/en/permalink/ahliterature268091
Source
Sci Rep. 2015;5:17951
Publication Type
Article
Date
2015
Author
Graeme T Swindles
Paul J Morris
Donal Mullan
Elizabeth J Watson
T Edward Turner
Thomas P Roland
Matthew J Amesbury
Ulla Kokfelt
Kristian Schoning
Steve Pratte
Angela Gallego-Sala
Dan J Charman
Nicole Sanderson
Michelle Garneau
Jonathan L Carrivick
Clare Woulds
Joseph Holden
Lauren Parry
Jennifer M Galloway
Source
Sci Rep. 2015;5:17951
Date
2015
Language
English
Publication Type
Article
Abstract
Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms.
PubMed ID
26647837 View in PubMed
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Organic matter control on the distribution of arsenic in lake sediments impacted by ~65years of gold ore processing in subarctic Canada.

https://arctichealth.org/en/permalink/ahliterature286986
Source
Sci Total Environ. 2017 Oct 27;
Publication Type
Article
Date
Oct-27-2017
Author
Jennifer M Galloway
Graeme T Swindles
Heather E Jamieson
Michael Palmer
Michael B Parsons
Hamed Sanei
Andrew L Macumber
R. Timothy Patterson
Hendrik Falck
Source
Sci Total Environ. 2017 Oct 27;
Date
Oct-27-2017
Language
English
Publication Type
Article
Abstract
Climate change is profoundly affecting seasonality, biological productivity, and hydrology in high northern latitudes. In sensitive subarctic environments exploitation of mineral resources led to contamination and it is not known how cumulative effects of resource extraction and climate warming will impact ecosystems. Gold mines near Yellowknife, Northwest Territories, subarctic Canada, operated from 1938 to 2004 and released >20,000t of arsenic trioxide (As2O3) to the environment through stack emissions. This release resulted in elevated arsenic concentrations in lake surface waters and sediments relative to Canadian drinking water standards and guidelines for the protection of aquatic life. A meta-analytical approach is used to better understand controls on As distribution in lake sediments within a 30-km radius of historic mineral processing activities. Arsenic concentrations in the near-surface sediments range from 5mg·kg(-1) to over 10,000mg·kg(-1) (median 81mg·kg(-1); n=105). Distance and direction from the historic roaster stack are significantly (p
PubMed ID
29111252 View in PubMed
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Spheroidal carbonaceous particles are a defining stratigraphic marker for the Anthropocene.

https://arctichealth.org/en/permalink/ahliterature263087
Source
Sci Rep. 2015;5:10264
Publication Type
Article
Date
2015
Author
Graeme T Swindles
Elizabeth Watson
T Edward Turner
Jennifer M Galloway
Thomas Hadlari
Jane Wheeler
Karen L Bacon
Source
Sci Rep. 2015;5:10264
Date
2015
Language
English
Publication Type
Article
Abstract
There has been recent debate over stratigraphic markers used to demarcate the Anthropocene from the Holocene Epoch. However, many of the proposed markers are found only in limited areas of the world or do not reflect human impacts on the environment. Here we show that spheroidal carbonaceous particles (SCPs), a distinct form of black carbon produced from burning fossil fuels in energy production and heavy industry, provide unambiguous stratigraphic markers of the human activities that have rapidly changed planet Earth over the last century. SCPs are found in terrestrial and marine sediments or ice cores in every continent, including remote areas such as the high Arctic and Antarctica. The rapid increase in SCPs mostly occurs in the mid-twentieth century and is contemporaneous with the 'Great Acceleration'. It therefore reflects the intensification of fossil fuel usage and can be traced across the globe. We integrate global records of SCPs and propose that the global rapid increase in SCPs in sedimentary records can be used to inform a Global Standard Stratigraphic Age for the Anthropocene. A high-resolution SCP sequence from a lake or peatland may provide the much-needed 'Golden Spike' (Global Boundary Stratotype Section and Point).
PubMed ID
26020614 View in PubMed
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