Evidence for the enhanced lability of dissolved organic matter following permafrost slope disturbance in the Canadian High Arctic

2011 ◽  
Vol 75 (22) ◽  
pp. 7226-7241 ◽  
Author(s):  
Gwen C. Woods ◽  
Myrna J. Simpson ◽  
Brent G. Pautler ◽  
Scott F. Lamoureux ◽  
Melissa J. Lafrenière ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
High Arctic ◽  
Canadian High Arctic

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

2018 ◽  
Vol 52 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jun-Jian Wang ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
André J. Simpson ◽  
Yves Gélinas ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Active Layer ◽  
Pond Water ◽  
High Arctic ◽  
Canadian High Arctic ◽  
Organic Matter Composition

scholarly journals Seasonal hydrology and permafrost disturbance impacts on dissolved organic matter composition in High Arctic headwater catchments

2017 ◽  
Vol 3 (2) ◽  
pp. 378-405 ◽  
Author(s):  
J. Fouché ◽  
M. J. Lafrenière ◽  
K. Rutherford ◽  
S. Lamoureux
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Active Layer ◽  
Climate Change Impacts ◽  
High Arctic ◽  
Low Molecular Weight ◽  
Headwater Catchments ◽  
Precipitation Regimes ◽  
Spring Freshet

Arctic landscapes are experiencing intense warming and modification of precipitation regimes with climate change. Permafrost disturbances and climate change impacts on hydrology of Arctic watersheds are likely to modify the quantity and composition of exported dissolved organic matter (DOM). In July 2007, intense rainfall and active layer thickening caused widespread active layer detachments at Cape Bounty, Melville Island (Canada). This study investigates the impacts of seasonal hydrology and permafrost disturbance on DOM composition exported from High Arctic headwater catchments. In 2012, streams were sampled from three disturbed catchments and one undisturbed catchment. The composition of DOM was characterized using absorbance and fluorescence spectroscopy. DOM was mostly exported during the spring freshet. Throughout this period, the undisturbed catchment exported humified DOM with high humic-like fluorescence that likely originated from runoff through shallow organic rich soil. In contrast, DOM exported from disturbed catchments was fresher, less humified with a high proportion of low molecular weight humic acid. We demonstrate that disturbed catchments delivered likely more labile DOM derived from either thawed permafrost or enhanced microbial activity. If this labile DOM comes from an ancient pool, as indicated by other studies at this site, disturbances may strengthen the permafrost carbon feedback on climate change.

scholarly journals Redistribution of soil organic matter by permafrost disturbance in the Canadian High Arctic

2016 ◽  
Vol 128 (3) ◽  
pp. 397-415 ◽  
Author(s):  
David M. Grewer ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
Myrna J. Simpson
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
High Arctic ◽  
Canadian High Arctic

scholarly journals Diverging pond dissolved organic matter characteristics yield similar CO2 flux potentials in a disturbed High Arctic landscape

2020 ◽  
Author(s):  
Joanne K. Heslop ◽  
Jacqueline K.Y. Hung ◽  
Huan Tong ◽  
Myrna J. Simpson ◽  
Fiona M. Chapman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Co2 Flux ◽  
High Arctic

Biomarker assessment of organic matter sources and degradation in Canadian High Arctic littoral sediments

2010 ◽  
Vol 100 (1-3) ◽  
pp. 75-87 ◽  
Author(s):  
Brent G. Pautler ◽  
Janice Austin ◽  
Angelika Otto ◽  
Kailey Stewart ◽  
Scott F. Lamoureux ◽  
...  
Keyword(s):  
Organic Matter ◽  
High Arctic ◽  
Canadian High Arctic ◽  
Organic Matter Sources ◽  
Littoral Sediments

scholarly journals Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments

2019 ◽  
Vol 16 (23) ◽  
pp. 4535-4553 ◽  
Author(s):  
Caroline Coch ◽  
Bennet Juhls ◽  
Scott F. Lamoureux ◽  
Melissa J. Lafrenière ◽  
Michael Fritz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
High Arctic ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Low Arctic ◽  
Arctic Rivers ◽  
Flow Pathways ◽  
Small Catchments

Abstract. Climate change is affecting the rate of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances results in the release of carbon dioxide and methane to the atmosphere and to an increase in lateral dissolved organic matter (DOM) fluxes. Whereas riverine DOM fluxes of the large Arctic rivers are well assessed, knowledge is limited with regard to small catchments that cover more than 40 % of the Arctic drainage basin. Here, we use absorption measurements to characterize changes in DOM quantity and quality in a low Arctic (Herschel Island, Yukon, Canada) and a high Arctic (Cape Bounty, Melville Island, Nunavut, Canada) setting with regard to geographical differences, impacts of permafrost degradation, and rainfall events. We find that DOM quantity and quality is controlled by differences in vegetation cover and soil organic carbon content (SOCC). The low Arctic site has higher SOCC and greater abundance of plant material resulting in higher chromophoric dissolved organic matter (cDOM) and dissolved organic carbon (DOC) than in the high Arctic. DOC concentration and cDOM in surface waters at both sites show strong linear relationships similar to the one for the great Arctic rivers. We used the optical characteristics of DOM such as cDOM absorption, specific ultraviolet absorbance (SUVA), ultraviolet (UV) spectral slopes (S275–295), and slope ratio (SR) for assessing quality changes downstream, at base flow and storm flow conditions, and in relation to permafrost disturbance. DOM in streams at both sites demonstrated optical signatures indicative of photodegradation downstream processes, even over short distances of 2000 m. Flow pathways and the connected hydrological residence time control DOM quality. Deeper flow pathways allow the export of permafrost-derived DOM (i.e. from deeper in the active layer), whereas shallow pathways with shorter residence times lead to the export of fresh surface- and near-surface-derived DOM. Compared to the large Arctic rivers, DOM quality exported from the small catchments studied here is much fresher and therefore prone to degradation. Assessing optical properties of DOM and linking them to catchment properties will be a useful tool for understanding changing DOM fluxes and quality at a pan-Arctic scale.

scholarly journals Characterizing organic matter composition in small Low and High Arctic catchments using terrestrial colored dissolved organic matter (cDOM)

2019 ◽  
Author(s):  
Caroline Coch ◽  
Bennet Juhls ◽  
Scott F. Lamoureux ◽  
Melissa Lafrenière ◽  
Michael Fritz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
High Arctic ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Low Arctic ◽  
Arctic Rivers ◽  
Flow Pathways ◽  
Small Catchments

Abstract. Climate change is an important control of carbon cycling, particularly in the Arctic. Permafrost degradation through deeper thaw and physical disturbances result in the release of carbon dioxide and methane to the atmosphere and to an increase in riverine dissolved organic matter (DOM) fluxes. Whereas riverine DOM fluxes of the large Arctic rivers are well assessed, knowledge is limited with regard to small catchments that cover more than 40 % of the Arctic drainage basin. Here, we use absorption measurements to characterize changes in DOM quantity and quality in a Low Arctic (Herschel Island, Yukon, Canada) and a High Arctic (Cape Bounty, Melville Island, Nunavut, Canada) setting with regard to geographical differences, impacts of permafrost degradation and rainfall events. We find that DOM quantity and quality is controlled by differences in vegetation cover and soil organic carbon content. The Low Arctic site has higher SOCC and greater abundance of plant material introducing higher lignin concentrations into the aquatic system and resulting in a stronger color of DOM than in the High Arctic. There is a strong relationship between dissolved organic carbon (DOC) concentration and absorption characteristics (cDOM) for surface waters at both sites similar to the one for the great Arctic rivers. We used the optical characteristics of DOM such as cDOM absorption, Specific UltraViolet Absorbance SUVA, UltraViolet UV Slope, Slope Ratio for assessing quality changes downstream, at baseflow and stormflow conditions and in relation to permafrost disturbance. DOM in streams at both sites demonstrated optical signatures indicative of photodegradation downstream processes, even over short distances of 2000 m. It was determined that flow pathways and the connected hydrological residence time control DOM quality. Deeper flow pathways allow the export of permafrost-derived DOM, whereas shallow pathways with shorter residence times lead to the export of fresh near-surface derived DOM. Compared to the large Arctic rivers, DOM quality exported from the small catchments studied here is much fresher and therefore prone to degradation. This work shows that optical properties of DOM will be a useful tool for understanding DOM sources and quality at a pan-Arctic scale.

Structural variation in the songs of Atlantic walruses breeding in the Canadian High Arctic

2003 ◽  
Vol 29 (2) ◽  
pp. 297-318 ◽  
Author(s):  
Becky Sjare ◽  
Ian Stirling ◽  
Cheryl Spencer
Keyword(s):  
Structural Variation ◽  
High Arctic ◽  
Canadian High Arctic
Sign in / Sign up

Export Citation Format

Share Document