Life under ice in Lake Onego (Russia) – an interdisciplinary winter limnology study

This special issue of Inland Waters focuses on recent under-ice research in Lake Onego, Russia. Compared to open waters, research on ice-covered lakes is sparse because of the demanding work environment and logistics in the field (Kirillin et al. 2012). In the past, large lakes in particular, such as the European Lakes Onego (61°36′10.52″N, 35°34′22.42″E) and Ladoga (61°00′0.00″N, 31°00′0.00″E), were not typically studied during their ice-cover periods. Today, however, substantial concerns exist about the potential effects of rapid climate warming and the resulting reduction in ice cover in high latitude lakes. Subsequently, scientific interest in boreal lakes has strongly increased (Brown and Duguay 2010). At the same time, these lakes are important for drinking water, transport, hydropower, and recreation (Rukhovets and Filatov 2010, Magnuson and Lathrop 2014) and represent outstanding biological resources. Therefore, the sustainable use of water and conservation of biodiversity in Lakes Ladoga and Onego were declared a high priority in 2013 by the Russian Security Council (http://kremlin.ru/events/president/news/19655). Given these circumstances, a better understanding of the role of ice cover on ecological characteristics of these large lakes is required. Lake Onego, a lake of glacial-tectonic origin located in Karelia (Russia), offers a fascinating place for such studies. As the second largest lake on the European continent (9600 km2, 292 km3; Filatov and Rukhovets 2012), Lake Onego is ice covered for several months each winter, which strongly influences its characteristics, including the occurrence of endemic species. Excellent research infrastructure, collaboration opportunities, and expertise in winter limnology (Jonas et al. 2003) are available from the Northern Water Problems Institute, Karelian Research Center of the Russian Academy of Sciences (NWPI-KRC-RAS; http://nwpi.krc.karelia.ru/e/), located on the shore of Lake Onego in Petrozavodsk. The Limnology Center of the Swiss Federal Institute of Technology Lausanne (LIMNC-EPFL; https://www.epfl.ch/research/domains/limnc/) was proposed to launch a research initiative supported by the Fondation pour l’Etude des Eaux du Leman (FEEL). Hence, we designed a multidisciplinary project on Lake Onego during late winter and spring from 2015 to 2017 to investigate physical, geochemical, and biological under-ice processes in this seasonally ice-covered lake. Additional fields of research included hydrology, paleolimnology, and remote sensing. The LIMNC-EPFL and the NWPI-KRC-RAS jointly implemented this project. The following 7 publications on Lake Onego are the outcome of this multidisciplinary project. We consider this contribution a first step toward a more integrated understanding of winter limnological processes and hope to stimulate follow-up investigations on these fascinating aquatic systems.