The thing in the centre is the centric diatom. The scaley things around are the coccoliths, or calcified scales, of the haptophytes Reticulofenestra clustering around it. The exact nature of this relationship is unknown...
No, I don't know what's going on - but it's a very cool scanning EM (actually, everything is cool when you view it with an electron microscope).
Also, note the interference contrast micrograph below: "Trichodina is a cute little peritrich (group that includes the coiled-stemmed-trumpet Vorticella)... the creature is like a miniature robotic vacuum cleaner, vacuuming fish gills..."
Both images found at Skeptic Wonder, via Uncertain Times.