The impact of an asteroid that struck Earth 66 million years ago left a crater known as Chicxulub based on research. Photosynthesis shut down after a large amount of debris was projected into the atmosphere. The crater, which is about 20 miles deep, resulted in the formation of the Gulf of Mexico. Blue-green algae, otherwise known as cyanobacteria, were found dwelling within fossilized plants that were washed into the crater after the incident, and survived. Cyanobacteria live within plants’ cells and have the ability to generate food for the plants.

In 2016, geologists unearthed a foundation of rocks from Chicxulub and allowed scientists around the world to conduct research on how life returned from ground zero. A scientist from the Curtin University of Australia, Bettina Schaefer, along with her team, found preserved fats within the core of the rocks. This means that cyanobacteria and other living organisms in the water caused by a tsunami after the incident were present.