Proteus (2004)
Proteus is an animated documentary film written and directed by David Lebrun in 2004. It depicts a Nineteenth-Century understanding of the sea with particular emphasis on the life and work of German biologist and researcher Ernst Haeckel. One-celled microorganisms known as radiolarians feature prominently in Haeckel's fascination with the observable natural world and the underlying guiding principles assumed to be implicit in its very existence.
More at Wikipedia.