Seems like this article is more full of holes than a Swiss cheese factory...
Bad Astronomy's take on this. Lots and lots and lots of problems with every part of the paper.
Just one of the issues is about the "meteorite", and that is particularly illuminating - neither does the rock look like a meteorite, nor is any verifiable provenance information supplied.
They found an ordinary rock on the ground containing modern Earthly, non-fossilised diatoms and published a paper claiming it's diatoms from space! Looks like a junk paper IMHO.