How can algae help us investigate the past?

Imaging of organic signals in individual fossil diatom frustules with nanoSIMS and Raman spectroscopy

So basically…

Scientists can look at things trapped in the layers of rock known as sedimentary rock for clues about the conditions on Earth thousands and thousands of years ago. They find fossils in these rocks and one such type of fossil is called a diatom.

These are super prolific algae found everywhere even today but what’s important about these is that they have a special cell wall made out of silica, which researchers think can protect what’s inside the algae from disturbance over the millennia they’ve laid dead under a bunch of rock. In this case, the diatom fossils were over 12,000 years old!

Investigating what’s inside requires finding what’s inside, so a team of researchers has used powerful microscope imaging techniques to locate any organic matter like nitrogen inside the diatoms. They found high concentrations of this organic matter in the pores of the cell walls. Now they know where they can find it, they can get in there and find out precisely what it’s made of—using chemical analysis techniques—and get an accurate picture of the atmospheric and oceanic conditions of the time.

Interested? Read more here.