Life under the ice: extreme conditions or oases? Hudsonie21 project on winter limnology of thermokarst lakes

Thermokarst lakes are widespread in subarctic regions and contribute to global carbon (C) cycling. The recent degradation of permafrost means that the basic limnological and biogeochemical properties of these lakes are in a state of flux. Critical ecological processes possibly take place under the ice, and winter trophic interactions may have year-round repercussions on primary productivity, food availability for higher trophic levels and greenhouse gas (GHG) emissions. In this project, we aim to improve our knowledge about the physical and biogeochemical conditions during late winter, and on their effects on microbial and planktonic life. We are particularly interested in thermal and mixing regimes, oxygen concentrations, type and lability of dissolved and particulate organic C and sulphur, which are linked to the sequestration or release of toxic heavy metals. Temperature, oxygen and conductivity were followed with overwintering instruments and discrete profiles. We measured GHG production and consumption with a focus on winter storage. These processes will be linked to surface sediment and planktonic microbial communities (heterotrophic protists, bacteria, Archaea and viruses), studied with microscopy and molecular tools. These data will help us to determine whether thermokarst lakes in the Hudsonie21 study region are extreme environments that are hostile to life, or oases and refuges where aquatic organisms survive and perhaps thrive throughout the northern winter. List of measured variables: Profiles of T, DO, pH, conductivity and ORP (Hydrolab); seasonal profiles of T and DO (thermistor and MiniDOT); DOC, CDOM spectral absorption, CDOM fluorescence EEMs; TP, TN, SRP, major anions, major cations; sulphur & carbon species (structural analysis from 13CssNMR, 33SssNMR and MS); labile and total trace-elements in water, lake sediment and surrounding soils (ICP-MS); Hg and metals in water, surface lake sediment and surrounding soils; dissolved CO2 and CH4 (headspace method); procaryote abundance (flow cytometry), bacterial activity (tritiated leucine), primary production (PE curves); DNA and RNA extraction (one pond) to describe the diversity of viruses (Myoviridae, Chlorovirus), archaea, bacteria and eukaryotes by Multiplex sequencing with MiSeq-Illumina© platform; pigments (HPLC); phytoplankton, heterotrophic nanoflagellates & zooplankton abundance; fatty acids; laboratory experiments to test microbial and photochemical degradation of CDOM.

Metadata Access
Creator Laurion, Isabelle; Canario, Joao; Culley, Alexander; Lovejoy, Connie; Pilote, Martin; Rautio, Milla; Vincent, Warwick; Centre for Northern Studies
Publisher Canadian Cryospheric Information Network
Contributor Polar Data Catalogue
Publication Year 2016
Rights Research programs, CCIN, or ArcticNet take no liability for the use or transmission of this data
OpenAccess true
Contact isabelle.laurion(at); pdc(at)
Language English
Format Computer file
Discipline Biogeochemistry
Spatial Coverage (-78.000W, 55.000S, -77.000E, 56.000N)
Temporal Coverage Begin 2016-03-19T00:00:00Z
Temporal Coverage End 2016-03-24T00:00:00Z