It's baitfish from what I can see on your graphs pictures, the last 2 show this very well.
Skiatook Lake this week looks like alien blob forms all over the lake with the small bait forms everywhere.
Wish i would have saved some screen grabs of it. Was very crazy and cool looking.

Thermocline is much easier to see with your 83z 2d. You will see a faint to aggressive line at certain depths. We were seeing a temp change around 25' at Skiatook this week.
Plankton will cause your 2d 83z graph to a blur up a solid color. if you get up to Colorado on Blue Mesa Reservoir or one of those lakes with heavy zooplankton, you can actually see the plankton at top 10-20 feet this time of year with your eyes snd it looks like little white-green teeny dots everywhere in the water and both your sidescan/downsan and 2d 83z will be a blur in this area. It's kinda freaky looking in the water seeing the plankton everywhere on surface.

FYI for the Hybrid fishermen. Hit Skiatook from sunup too around 9:30 or so and watch for schoolers splashing on top.