Last year marked the 125th anniversary of Stephen A. Forbes’ classic paper “The Lake as a Microcosm” (Forbes 1887): “A lake is a little world within itself—a microcosm within which all the elemental forces are at work and the play of life goes on in full but on so small a scale as to bring it easily within the mental grasp.” In his essay, Forbes foreshadowed the ecosystem concept, and, for many, “The Lake as a Microcosm” marks the beginning of ecology as a science. Lakes are one of several types of aquatic ecosystems that have been the focus of ecological research since. While none of these are now viewed as “little worlds within themselves” and are clearly embedded in the surrounding landscape, Forbes’ view that lakes function as isolated and simplified (hence understandable) systems provided encouragement to early limnologists and continues to inspire the (aquatic) ecologists of today.

The subject editors of Aquatic Ecology wanted to commemorate the 125th anniversary of “The Lake as a Microcosm” and are convinced that, 125 years later, aquatic ecosystems still have much to offer to ecology. Lakes played a key role in the development of the concept of alternative stable states in ecosystems (Scheffer et al. 1993) and are valued as sentinels of climate change (Adrian et al. 2009). We invited Lars-Anders Hansson and colleagues to review how the concepts and ideas formulated by Forbes more than a century ago are reflected in their work on Lake Krankesjön in southern Sweden (Hansson et al. 2013). Aquatic Ecology has always published conceptual research on lakes and will continue to do so in the future.