I attended a bridal shower Saturday afternoon that was held for a geology friend. Everyone at the shower was either a geologist or worked with geologists. The hostess wanted to create something that reminded the bride-to-be of her home and went with a stromatolite cake! Now, the geologists in the room don’t blog, so I’ve taken it upon myself to post pictures of her cake as a tease for the Accretionary Wedge #30. I’ll post my own creation later in the week.
ok, so what is a stromatolite and why on earth is this cake a weird blue-green color?
Stromatolites are some of the earliest forms of life that have been found on Earth. They are comprised on microbial mats within water that trap sediments into layers. The microbes are made up of cyanobacteria, which are also known as blue-green algae (hence the food coloring choice!). There may also be non-bacterial stromatolites, but we’ll avoid that topic for the moment.
The oldest preserved stromatolites at the current moment are somewhere between 2.7 and 3.5 billions of years old (I’m not getting into that uncertainty right now), which considering we don’t get hard parts until the Cambrian explosion ~580 million years ago is quite amazing.
Australian stromatolite (note the layering):
Some of widest arrays of types of stromatolites can be seen at Glacier National Park (~800 million years old):
Cambrian stomatolites in Sarasota Springs, NY:
The great thing is that unlike many organisms that have come & gone on the planet, we can still go and see live versions (they dominated in the Proterozoic, but are relatively rare now). Here are some modern examples in Shark Bay off of Australia: