Thalassiosirales is an order of centric diatoms.

[1] Species in the order Thalassiosirales are common in brackish, nearshore, and open-ocean habitats, with approximately the same number of freshwater and marine species.

[2] The Thalassiosirales species Thalassiosira pseudonana was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing.

[3] T. pseudonana was selected for this study because it is a model for diatom physiology studies, belongs to a genus widely distributed throughout the world's oceans, and has a relatively small genome at 34 mega base pairs.

Scientists are researching on diatom light absorption, using the marine diatom Thalassiosira.