As our water temperatures start to rise, especially in water less than 20′, it’s common for algae to start multiplying in the upper part of the water column. When this happens it’s called an “algaee-bloom”. Many anglers move away from these turbid water areas, but I know that some fish, like walleye, will actually move into these areas because less light penetrates the water and they can feed more effectively often cruising into shallow water even on a bright sunny day to feed.
This screen-grab from the Raymarine HybridTouch with CHIRP DownVision shows clearly the thicker algae on the surface going even down to almost 6′, and as we move deeper, the algae only blossoming closer to the surface. In this situation we came out of a warmer creek mouth which you can see on the C-Map chart (left-side of screen), where the water was warmer than the main lake.
In the above screen-grab you can see the algae particles are larger and suspended throughout the water column.