Base de données de recherche des TNO

étiquettes: physical sciences, limnology, food web, glaciology

Objectif(s): The overall objective of this research component is to improve knowledge on lake ice and its effect on food webs/productivity in small Arctic lake systems in order to better predict changes that could occur under changing climate.

Description du projet: The overall objective of this research component is to improve knowledge on lake ice and its effect on food webs/productivity in small Arctic lake systems in order to better predict changes that could occur under changing climate. All other research activities related to this work have been reviewed/approved/fully-licensed as part the overall research project “Hydro-ecological Responses of Arctic Tundra Lakes to Climate Change and Landscape Perturbation” (ARI Scientific Research Licences 14502 & 14559; ILA Right Number ILA05IN009; DFO Licence to Fish for Scientific Purposes; AUP Number FWI-ACC-2009-034). In this new research component, the researcher will install an automated ice buoy and subsurface mooring system for continuous monitoring of weather conditions, lake ice cover (formation, growth over winter, breakup in spring), light penetration into the lake (through ice in winter), and water quality in Noell Lake. Description of the Ice Buoy and Mooring System The ice buoy and mooring system is composed of two parts: (i) a lake buoy with weather instruments on top (to measure sunlight, windspeed, wind direction, air temperature, relative humidity, and air pressure), and sensors along its length below the waterline to measure light penetration into the lake water (through ice in winter) and to measure water quality information near the lake surface (temperature, dissolved oxygen, and water chemistry); (ii) a subsurface mooring which includes a tethered array of water quality probes to measure temperature, dissolved oxygen, and water chemistry at a variety of depths down to the lake bottom, and an Ice Profiler Sensor (IPS) to measure the development, growth and decay of the lake ice cover through the cold season. Data collected by the subsurface mooring system are transmitted to the adjacent Ice Buoy using acoustic modems located at the base of the mooring and on top of the buoy. These data are added to the data collected by the instruments on the buoy by way of on-board computer software. The buoy then transmits all the data to a satellite which, in turn, transmits to a base station located at the Water & Climate Impacts Research Centre (W-CIRC) located at the University of Victoria (or other location). There is a 2-way capability using the satellite telemetry which allows the researcher to manage remotely both the ice buoy and subsurface mooring components. The system is designed for year round deployment and due to an acoustic release on the subsurface mooring, all components are recoverable and will be removed from the lake at the end of the research project. Installation of the Ice Buoy and Mooring System The Ice Buoy and Mooring System will be pre-assembled and then deployed by helicopter, either in September prior to freeze-up of the lake (to capture lake ice formation this year), or during the cold season after the lake ice has formed and using the ice cover as a platform to assist in the installation. A location in Noell Lake for installation of the buoy system will be selected to ensure that the buoy placement will not interfere with the use of the lake for ice fishing, transportation (e.g. snowmobile trails), local hunting and harvesting activities, etc. The buoy will be clearly marked with reflective tape, and once the lake ice has formed we will surround the location with bright orange pylons/floats, to prevent people from accidentally running into the buoy (by boat in summer or by snowmobile in winter) at night or during the dark winter months. Data Collection and Analysis Data collected using the buoy system will be used to monitor lake ice development through the entire ice season (initial freeze-up in the fall, its growth through winter to its maximum thickness, and breakup in spring). Lake water quality measurements collected continuously through the entire year will be used along with other field observations for analyses related to food webs/productivity as described in the previously approved/licensed project description. The entire dataset including new information on lake ice will allow the researcher to look at the effects that lake ice has on food webs/productivity. Computer modeling activities will be conducted to validate lake ice models using new information on lake ice. To communicate results to individuals and communities in the North, the researcher plans to hold annual community-based meetings and consultations in northern communities to inform local residents in the region of the nature and significance of the research, and to provide updates on what they have learned (key findings) as the work progresses. The researchers also plan to visit the schools to reach out to the youth. Information will also be made available through a project website, posters, brochures, fact sheets, etc. The fieldwork for this study will be conducted from September 22, 2009 to December 31, 2009.