This image, a recent Picture of the Day at NASA’s Earth Observatory, takes a big view of something very small – lots and lots and lots of single-celled organisms multiplying in the waters off northern Russia.
This is a bloom of phytoplankton, microscopic plants that float around all day turning sunlight into energy. This particular kind of phytoplankton does something else interesting – it creates calcium carbonate armor for itself. Coccolithophores do this by taking carbon dioxide out of the atmosphere. Since carbon dioxide is one of the main gases responsible for global warming, this could be a very useful trick indeed.
Especially when you get enough coccolithophores that you can see them from space.
It’s also where chalk comes from. Teeny-tiny limestone armor plates.