One time a fellow intern and I were isolating single colonies of spirulina (many bright green algae* cells in a spiral [1], which is roughly 50 micron wide and

One time a fellow intern and I were isolating single colonies of spirulina (many bright green algae* cells in a spiral [1], which is roughly 50 micron wide and maybe 15 micron tall, if memory serves), and I got one colony on it's own in a drop of water under a microscope (using a special pipette & the wick effect for suction). I took my eyes off of the eyepiece, and looked at the drop of water. I could see a bright green dot in the middle, right where I'd left my spirulina. I asked the other intern if they saw it too; they did. It was a magical moment. I had a similar experience when I was doing something with H. pluvalis (an algae that turns bright red and forms a film under stress [2], you've likely seen it in a birdbath or shallow puddle) and I put this film under the microscope, looked at it, and saw it was 1 cell thick. I'm confident if I had gotten a single one of those cells on it's own, I could've seen it. Can't confidently remember how big they were, but large on the scale of cells you find in a drop of water (maybe 25 micron in diameter?), but smaller than most animal cells. * Technically a cyanobacteria and not an algae, but if a lay person looked at a pond of it they'd say to themselves, "that's a bunch of algae" [1] https://images.fineartamerica.com/images-medium-large/1-spirulina-cyanobacteria-light-micrograph-sinclair-stammers.jpg https://images.fineartamerica.com/images-medium-large/1-spir... [2] https://images.squarespace-cdn.com/content/51511761e4b0323b0cd00500/1497555135471-V5Q9LG80KNZGOHWTBCN4/DSC02300.JPG?format=1000w&content-type=image%2Fjpeg https://images.squarespace-cdn.com/content/51511761e4b0323b0...