Two coleps ciliates engaged in a conversation. Music by Andrew Keoghan.

A single cellular predator, Collodictyon triciliatum, finds and engulfs two green algae cells. These microscopic predators are common in freshwater. I isolated this strain from Central Park in New York City. It’s now growing happily in the laboratory on a steady diet of greens. This video is sep up six times for your viewing pleasure.

This little character is an amoeba. It's shaped like a blob. Amoebas are predators, they need to eat to survive. In this clip, you can see it trying to eat a long alga. The alga is far too long to fit inside the amoeba, and sure enough (after a thorough investigation) the amoeba gives up on its lunch. This clip is sped up four times, so covers about four minutes in real-time. Amoebas are slow.

Lacrymaria olar means tear of the swan. It's a ciliate with unusual properties. It has a "head" that sits atop an extendable "neck". The neck can extend to several times the length of the body. L. olar uses this useful neck to explore its environment, looking for food to eat.

Those tiny little strands you can see darting around in this video are filamentous bacteria. Filamentous bacteria are bacteria that grow in long, very thin, chains. You can spot them because they are much longer than they are wide. Different species of filamentous bacteria occur just about everywhere; in water, soil, and inside your own body. These ones were living in a pond in the Brooklyn Botanical Gardens. They are thriving amongst a bloom of a green alga.

The big green colonies are a green alga called pandorina. The colonies get bigger as they get older, and you can see a whole range of sizes here. The small brownish cells are algae called cryptomonads. These two types of algae are different colors because they contain plastids with different pigments. They both originally came from the lake in Central Park.