Limnology in the 21st century: the importance of freshwater ecosystems as model systems in ecology and evolution

In 1990, in order to celebrate the 50^th anniversary of the former Italian Institute of Hydrobiology, now Institute of Ecosystem Study, a special issue summarising the advances in limnology was published by Memorie dell’Istituto Italiano di Idrobiologia, now Journal of Limnology. After 25 years, it is time again for a synthesis of what limnology did in the past, but mostly for suggestions on widening the horizon of the discipline, by including new tools and techniques. We hope that limnology will live long, and we celebrate the 75^th anniversary of the Institute with this special issue, containing manuscripts on the advances in the field and introducing recent and new lines of research in lentic waters studies.