Thalassiosira pseudonana

Thalassiosira pseudonana, or Thaps, is a unicellular diatom with silica cell walls. The organism is predicted to be a "winner" in the struggle for survival caused by Ocean Acidification. As the first eukaryotic marine phytoplankton to have its whole genome sequenced, the diatom is widely used in oceanic research.


Growth in Ocean Water

We cultured Thaps in samples of water from several locations around Puget Sound to determine whether it would be feasible for teachers to use the ocean water they have on hand for growing this model organism in their classrooms. We found that, although Thaps will grow in most ocean water, samples taken from choppy, moving waters work the best. We also found that filtering the ocean water with a high quality filter increases the rate and duration of growth in the culture.

When we tested the growth of Thaps in both unfiltered and filtered Puget Sound water, we found that the cultures grew significantly better in filtered water. Nalgene filters were able to get rid of most of the contamination in the Puget Sound water, allowing for the cultures to flourish. Note that our control culture was Thaps grown in ESAW. ESAW is a solution that is known to have all the nutrients Thaps need to grow successfully.