In this episode of Pondlife, Cyanobacteria from Pond to Lab, microbiologist Sally Warring hunts for cyanobacteria in New York City’s Central Park. Then she takes the samples back to her lab at the American Museum of Natural History to grow and study her lab cultures. Plus: Watch a ciliate eat a cyanobacterium like a strand of spaghetti. She explains:
We are surrounded by hidden microscopic worlds filled with fascinating life forms… Today I’m out looking for a group of organisms that evolved over two billion years ago. These organisms were the first to live by photosynthesis. That’s the process of using sunlight to make sugars and then those sugars are used to power the cell.
A byproduct of photosynthesis is oxygen, and two billion years ago these organisms became so abundant that they completely changed the Earth’s atmosphere. It went from one that was very oxygen-poor, to the oxygen-rich atmosphere that we live in today. These microbes are called cyanobacteria and lucky for me, they are just as abundant today as they were two billion years ago.
Two examples, the genera dolichospermum and aphanizomenon:
Cyanobacteria blooms look like blue-green paint or scum, thriving in calm, warmer waters. The blooms can be toxic to animals, and there’s “evidence indicating that cyanobacterial blooms are increasing in frequency, magnitude and duration globally” and that climate change is a factor. Warring explains:
The cyanobacterium blooming in the Lake belongs to the genus Microcystis. Microcystis colonies are made up of many individual cells suspended in a clear mucus. A colony may start as one cell… which divides to become two cells… then four… and so on until some colonies are large enough to see with the naked eye.
The colonies grow fast in warm summer waters, and when their numbers get dense enough, we call this a bloom. Many cyanobacterial species are bloom-forming, and you can distinguish each species by their unique colony shapes. One advantage of living as a colony is that when many individuals live together, tasks can be divided among the members.