1. Lake outlets are formed where streams become impounded by natural processes, or as the result of human activities. Water can drain from the surface of the lake, or from lower in the water column and the physico-chemical, and biotic, characteristics of these two types of lake outlets are very different during lake stratification.2. Temperature will have effects on the lake water and on the lake-outlet community. The effect of temperature on the surface waters of the lake will be of special importance since this is the region where the influence of solar radiation is at its highest. Warming of the surface waters of lakes will have many direct, and indirect effects, on the lake-outlet communities.3. Increasing temperature above levels currently found will have both advantages, and disadvantages for components of the lake-outlet communities.