October 17th, 2007 | | By Ken Mankoff

Last week was the first time I'd ever looked through a microscope, (which I prefer to think of as a 1/telescope), and so I don't know much about diatoms, but I do know they are beautiful.
Diatoms are single celled phytoplankton (very small floating plants). There are lots of different species of them, and they exist both in the water today and have in the past. When they die, they sink to the bottom and become part of the geologic record as they get covered, and preserved, by new layers.
They are useful in two primary ways. First, certain types and species existed at different points in the past, so they can be used to age-date the geologic record. In addition, diatom growth is a function of the climate at the time they were alive. So we can look at the diatoms in the core and based on the number of frustules we can infer the amount of sunlight they received. (Think of tree rings, only really really small.) The amount of sunlight can be used to infer whether there was an ice sheet over the water where the diatoms, and that part of the core, existed.
So far, in the top twenty or so meters of core, we have seen very few diatoms. Here are two images, one of a partial diatom and one complete.

Tags:
ANDRILL,
Antarctica,
fauna,
flora