ECOLAB > Agenda > The Cape Bounty Arctic Watershed Observatory: understanding the response of watersheds to climate and permafrost change

The Cape Bounty Arctic Watershed Observatory: understanding the response of watersheds to climate and permafrost change

Séminaire le 09 mars 2018 à 11h00

Intervenant : LAFRENIERE Melissa

Queen's University, Canada

Toulouse Campus ENSAT Toulouse Campus ENSAT

 

The Cape Bounty Arctic Watershed Observatory: understanding the response of watersheds to climate and permafrost change

 

LAFRENIERE Melissa

Queen's University, Canada

Vendredi 9 mars 2018, 11h00

ENSAT, Bâtiment C, salle 701

The Cape Bounty Arctic Watershed Observatory (CBAWO) was established in 2003 to investigate the hydrological processes and impacts associated with climate and permafrost change in the Canadian High Arctic.  Comprehensive data collection at the paired watersheds has spanned 2003 to 2017, a period containing both the coldest and warmest melt season conditions, including the warmest decade on record.  Through this period, the hydrological regime has transitioned from one that is predominantly nival (snowmelt) to one in which rainfall runoff and baseflow are increasingly important. This hydrological shift along with associated environmental changes have altered the seasonality and magnitude of material fluxes from these High Arctic watersheds.  Both localized physical permafrost disturbances and catchment-wide thermal permafrost disturbance (deep thaw) have resulted in soil and runoff perturbations, broadly increasing solute and nutrient flushing, with more intense sediment and solute impacts where physical disturbances have occurred.  The long-term nature of the research at CBAWO has also allowed us to investigate the recovery time to perturbations, which reveals that the recovery times diverge depending on the material. Where as sedimentary systems appear to recover in ~5 years, the dissolved fluxes can remain high for more than 5 years, due to repeated thermal perturbations. Our research also demonstrates that permafrost carbon in this setting is relatively old and labile, both in particulate and dissolved phases. Permafrost degradation has altered microbial activity in soils, and increased nitrification in disturbed settings, which points to complex biogeochemical responses to climate and permafrost change. Overall the sustained research activity at CBAWO has revealed new complexity in the hydrological and biogeochemical functioning of High Arctic watersheds.  Long term observatories like CBAWO provide critical context to place observations in, especially during periods of change and are necessary to develop a comprehensive understanding of hydrological change and water security in the region.

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