Together with heat and nutrients, light is one of the fundamental resources that regulate the productivity of aquatic ecosystems. However, compared with temperature and nutrients, data on light environment from aquatic systems, especially from lakes, are very scanty. Moreover, only few studies have considered the fact that light is also a very important top-down regulator due to its effect on the feeding efficiency of predators. The impacts of climate change on the structure and dynamics of aquatic food webs remain poorly understood. One reason for this is that most climate change scenarios have focused on the effects of rising water temperature and wind velocity and much less attention has been put to the fact that climate change will also affect the light environment of aquatic ecosystems, with fundamental effects on their food webs. In this application, research funds are applied to study the consequences of the forthcoming changes in the light climate of lakes. Moreover, changes in the light environment of lakes can also severely affect the success of lake restoration efforts. Several poorly known light-mediated regulatory mechanisms are studied. These are the effects of turbulence and light environment changes (including spectral variations) (1) on the feeding efficiency of fish and tactile invertebrate predators in the pelagic zone, (2) on the feeding efficiency of fish and visual invertebrate predators in the littoral zone. Additionally, as a novel approach in the second topic, the effects of littoral macrophytes on the feeding efficiency of planktivores via their effects on the light environment are taken into account. Each topic includes experimental studies and comparisons between different latitudes (Finland, Turkey, Argentina). With the collected new information, and by using a modelling approach, it is predicted how the light environment changes will affect the dominance relationships of visual and tactile predators in the food webs and how these changes are reflected in the possibilities of lake management.
|Effective start/end date||01/01/2010 → 31/12/2014|