This image, a recent Picture of the Day at NASA’s Earth Observatory [1], 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 [2] 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 [3]. Teeny-tiny limestone armor plates.