Lakes Ladoga and Onego are the greatest lakes in Europe. With a surface area of 17891 km² and a volume of 902 km³, the former is one of the top fifteen world's freshwater lakes and is only slightly smaller than Lake Ontario. Lake Onego's surface area is 9600 km² and it has a volume of 292 km³. The watershed of Lake Ladoga (258000 km²) extends through Northwestern European Russia and the eastern part of Finland, including the large Lakes Ilmen and Saimaa, and together these Great European Lakes are an important link in the Caspian-Baltic-White Sea waterway system. Their ecological state affects the water quality of the Neva River, the Gulf of Finland and the Baltic Sea. Thus any changes affect the operational use, environmental protection and management of water resources of a wide area and concern such issues as drinking, recreation, transport and energy.

The anthropogenic impact on the Lake Onego ecosystem is mostly determined by the sewage waters of the Petrozavodsk and Kondopoga industrial centres, while the river inflow makes the most impact on Lake Ladoga. Although the anthropogenic stress on the water ecosystems of the Great European Lakes has decreased over the last 15 years, there has been some simultaneous evidence of global warming. There is not enough current data to identify the climate-induced changes in lake ecosystems, but there is proof that the main cause of lacustrine ecosystem changes is determined by anthropogenic factors.

Coupled thermohydrodynamic and ecosystem models for Lakes Ladoga and Onego have been developed to study the contemporary situation, to understand the main mechanisms of the ecosystem transformation, and to learn what may happen in future under the varying antropogenic impact and climate changes. Lake Ladoga preserves its weak mesotrophic status while Lake Onego can be characterized as oligotrophic. Economic growth during the last seven years has led to the increasing anthropogenic impact on both their ecosystems.

The Great European Lakes are attracting the increasing attention of both researchers and end-users. This book is a synthesis of multifaceted interdisciplinary studies conducted by a team of experts in limnology, geography, biology, mathematical modeling and economy. The editors, Professors Rukhovets and Filatov, are the authors of numerous articles and books and are recognized as the foremost experts in their fields. Professor Rukhovets has been Director of the Institute of Economy and Mathematics in Saint-Petersburg and head of the laboratory of mathematical modeling since 1998 while Professor Filatov is currently Director of the Northern Water Problems Institute in Petrozavodsk, Russia.

Leond Aizikovich Rukhovets, professor, Doctor of Sciences, he started to work in Leningradean Branch of Steklov Mathematical Institute, USSR Academy of Sciences in 1959. In this Branch he worked during the period 1959-1965. The next periods 1965-1975,1975-1985 he was the scientific researcher in Lenigradean Branch of Central Institute of Mathematics and Economics, USSR Academy of Scieces and Leningradean Institute of Social and Economical Problems, USSR Academy of Sciences correspondingly. During period 1986-1990 he worked in Limnological Institute, USSR Academy of Sciences at Leningrad. He received his doctor's degree in computational mathematics in 1970 from Leningradean Branch of Steklov Mathematical Institute of USSR Academy of Sciences. His dissertation was devoted to study the finite element method (FEM) for solution boudary value problems for differential equations with partial derivatives. Later the interest of his investigations was focused upon the computational geophysicalhydrodynamics, models of large lakes circulation, ecosystem models and its implementation in conservation and managemtnt of water resources. In 1990 he was awarded a Doctor of Sciences degree in physics and mathematics. Leonid Rukhovets is the author more than 130 scientific articles and eight books. He took part in conferences and was visiting scientist in Oceanology Institute of Poland Academy of Sciences (Poland,1989), in Finland (1995, 1996, 1998, 2003,2006), USA(1999), Danmark (1999), Estonia (2006), Canada (2007). From 1998 to present Leonid Rukhovets is working in Institute for Economics and Mathematics at St.Petersburg, RAS as Director of Instirute and a head of the laboratory of mathematical modelling. He is a professor of State Marine Technical University.

Nikolai Nikolaevich Filatov, professor, Ph.D., He start work in limnilogical institute, Academy of Sc. and received his doctorate in geography in 1975 from the State University in Leningrad, where he conducted investigations of currents in Large Lakes. He are working in the Institute for Lakes Research of the Russian (then USSR) Academy of Sciences from 1971-1988 y., where his research interests become focused upon limnological, hydrophisics, and remote sensing.. He was awarded a D.Sc. degree in 1991. He has authored more than 300 scientific articles and 10 books. Now he is working in Nortern Water Problems Instittute as Director of the institute and head of laboratory of Geographical. His research activities continue to be directed toward the remote sensing, limnology and phisics of inland waters. He was visiting scientist in Canada (1979,1990), Austria, in International institute for Applied system analysis(1977), Finland (1983,1990,1993,1995-2002), Sweden (1992,1996, 2001, 2004).He is proffesor of State Pedagogical university (Petrozavodsk), President of Karelian Geographical society.