Planktonic protists

The word "plankton" shares a Greek root with "planet" (πλαγκτός, meaning drifting or wandering)-- an etymological link which seems particularly appropriate for these drifting microbes, spherical or stellate in form: 

Protists - Cells in the Sea from Parafilms on Vimeo.

This beautiful clip is one of a series called Plankton Chronicles, found via The Book of Barely Imagined Beings.

Dinoflagellates

These strange marine microbes are related to those which cause red tide. 

Characodictyon

This is an electron microscope image of a tiny fossil from the Precambrian era, the shell of a microbe (somewhat resembling modern radiolaria). It may be the oldest example of armor on a living creature. 

Image from Live Science. 

Diatom mandala

This beautiful design fits on a microscope slide, and the jewel-like objects that compose it are the shells of tiny marine microbes.

Image from Klaus Kemp's diatom art site. Diatom arrangements like these, along with similar arrangements of butterfly scales, were popular in the Victorian era.

Infusorial Animalcules

Plate from Pritchard's 'Infusorial Animalcules' 1852 showing illustrations of freshwater microscopic organisms.

Foraminifera

These are the shells of marine protists, each as small as a grain of sand. They are abundant in the fossil record, showing smooth transitions from stratum to stratum.

Xiphostylus and Saturnalis

 

Drawings from Report on the Radiolaria collected by H.M.S. Challenger during the years 1873-76. From Scientific Illustration.

Sticholonche

A marine microbe, one of the Radiolaria, which moves by "rowing" with its spines

Diatoms

Though these (more images here) look like glass beads or jewels-- and can likewise be used to make artistic designs-- they're actually the shells of  microscopic, unicellular marine algae.

Subdivided Platonic solids

We aim to show that a single deterministic process can generate a heterogeneous set of forms with an astounding degree of complexity.

Some of these forms resemble Ernst Haeckel's drawings of the marine protozoa called radiolaria:

They also look like less-chaotic versions of another beautiful 3D fractal, the Mandelbulb.