Interest in respiration in lakes has recently increased with the recognition that lakes can act as hot spots of carbon cycling, rapidly processing carbon and emitting CO2 into the atmosphere. Several ecosystem metabolism estimates and CO2 emission estimates from lakes are now available but temporal, in particular seasonal, variations are rarely considered. Most of the lakes in the northern hemisphere are, however, ice-covered during substantial portions of the year. Ice acts as a barrier to atmospheric exchange which often leads to an increase in water column CO2 (via respiration) and depletion in O2. Since the ice cover period is underrepresented in ecosystem metabolism estimates and CO2 emission estimates from lakes, using GLEON as a platform, we would like to synthesis temporally robust CO2 and O2 observations from the ice-covered period. In doing so we hope to establish the relationship between CO2/O2 and ice cover dynamics across climatic regions and lake ecosystem types. During the GLEON 16 meeting I will present a poster with conceptual hypotheses and initial analyses across a few ice-covered lakes to facilitate further discussions and ideas. If you are interested in contributing data or ideas to the project please get in touch with Blaize Denfeld by email (firstname.lastname@example.org) or at the GLEON 16 meeting.