Let me share with you a difference dinoflagellates and diatoms.
| Aspect | Dinoflagellates | Diatoms |
| Cell organization | Unicellular | Unicellular |
| Composition of cell wall | Cellulose-based plates, often with additional components like cellulose and silica | Cell walls made of silica (glass-like) |
| Shape | Diverse shapes, including armored and unarmored forms | Typically have a symmetrical or radial shape, with intricate patterns |
| Flagella | Two flagella, one in a longitudinal groove and one trailing | Lack flagella |
| Photosynthetic Pigments | · Chlorophyll a and c · Fucoxanthin · Peridinin | · Chlorophylls a and c · Fucoxanthin |
| Type of storage product | Starch | Lipids and chrysolaminarin |
| Habitat | Marine, some are freshwater | Marine and freshwater |
| Ecological Role | · Important group of producers second only to diatoms | · Major producers in aquatic ecosystem(marine and freshwater phytoplankton) · Play a crucial role in carbon cycling |
| Type of reproduction | · Asexual reproduction (binary fission) · Sexual reproduction (both homothallic and heterothallic) | · Asexual reproduction (binary fission) · Sexual reproduction (auxospores and gametes) |
| Toxin Production | Some species produce toxins, leading to harmful algal blooms (HABs) known as red tides | Generally not associated with toxin production, but some diatoms can produce domoic acid |
| Motility | Some species exhibit rapid spinning movement (whirling) | Typically non-motile, rely on water currents for dispersal |