The rest of it

Strands of Spirogyra, a green algae. They are among the myriads algae species which together are a major contributor of oxygen to Earth's atmosphere. The chlorophyl helices in charge are visible inside.

The 3d-appearance is due to a special microscopic technique, Differential Interference Contrast, DIC. The colors are just a play - a digital simulation of another technique, the Jamin-Lebedeff interference.