If a lake never turns over what happens to the surface dwelling organisms

The answer is it reduces their food supply. A lake is a body of water surrounded by land and not part of the ocean and larger than ponds. Most of the lakes are being drained by streams as well as the rivers.

If water in the lake never turns over, the surface dwelling organisms will have a reduce food supply. Most wildlife in the basin especially fish spend their entire life cycle in or near the lakes so they are the most affected. In addition, a lake is a body of fresh water surrounded by land and drained by rivers and streams.