Pyrocystis fusiformis in the light microscope

Pyrocystis fusiformis imaged by light microscopy. Pyrocystis is a photosynthetic, bioluminescent, marine dinoflagellate. The cell is about half a millimeter long and contains chloroplasts (the green structures) that do the photosynthesis. In the dark phase (=night) the chloroplasts are concentrated around the cell nucleus (in the center of the cell) and the cell is bioluminescent. In the light phase (=day) the chloroplasts are spread throughout the cell and the bioluminescence is paused (waste of energy to light up in daylight). As you can see the sample was contaminated with marine ciliates (the little guys buzzing around) that ended up taking over the entire culture. Check out this page on marine organism identification http://species-identification.org/index.php This Oak Crest project on pyrocystis won an award at the 2019 California Science & Engineering Fair http://csef.usc.edu/Current/Awards/J15.html