Environmental risk about water quality of lakes in Kurtna landscape reserve (Estonia) by the study of water temperature and dissolved oxygen.

• Main Authors: Touchart, Laurent, Millot, Camille, Maleval, Véronique, Koff, Tiiu, Kapanen, Galina, Terasmaa, Jaanus, Vandel, Egert, Vainu, M., Nedjaï, Rachid, Bartout, Pascal, Azaroual, Abdelhamid
• Other Authors: Centre d'Etudes pour le Développement des Territoires et l'Environnement (CEDETE), Université d'Orléans (UO), Laboratoire de Géographie Physique et Environnementale (GEOLAB), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Université Clermont Auvergne (UCA)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Institute of Ecology, Tallinn University, Pacte, Laboratoire de sciences sociales (PACTE), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Sciences Po Grenoble - Institut d'études politiques de Grenoble (IEPG)-Centre National de la Recherche Scientifique (CNRS), PHC PARROT
• Format: Article in Journal/Newspaper
• Language: French
• Published: HAL CCSD 2013
• Subjects: ice-covered lake; water temperature; inverse stratification; dissolved oxygen; Estonia; Estonie; oxygène dissous; stratification inverse; banquise lacustre; température de l'eau; geo; envir; banquise
• Online Access: https://hal.archives-ouvertes.fr/hal-00933395v2/file/TAP%20Risque%20Kurtna%202013.pdf; https://hal.archives-ouvertes.fr/hal-00933395

International audience Environmental risk about water quality of lakes in Kurtna landscape reserve (Estonia) by the study of water temperature and dissolved oxygen. The Kurtna reserve (North-Eastern Estonia) includes about forty lakes of hydro-glacial origin, among which the most are kettle hole lakes. Their level and the quality of water are conditioned by aquifers, which are threatened by industrial activities (sand quarry, peat production and oil shale excavation). The paper presents results of a field campaign in March 2013, for measuring water temperature, dissolved oxygen and salinity in two ice-covered lakes (Martiska and Nõmme). Martiska is a closed lake. A large (from 0 °C to 4 °C) inverse thermal stratification takes place under the ice. The very thick anoxic layer may be caused by the cumulating effect of the ice barrier and the consumption in a rich in organic matter lake. Nõmme fits in a hydrographical chain with tributaries and an emissary. The inverse thermal stratification is disturbed by a well delimited mid-layer. Temperature, dissolved oxygen and salinity show that it is probably the fluvial water body, which has entered the lake. The hypothesis is confirmed by the study of the river plume. This inflow is rich in dissolved oxygen. We may suggest, that the lakes with an affluent are less threatened by the winter lack of oxygen than the closed lakes of the region.