What distinguishes a diatom from other algae?

A diatom is distinguished from other algae primarily by its structured cell walls that contain silica, which is a characteristic feature. This silica composition leads to unique and intricate patterns in the cell walls that can influence the ecology of aquatic environments. Diatoms are often found in both marine and freshwater systems and play essential roles in these ecosystems, particularly in terms of primary production due to their ability to photosynthesize.

The presence of chlorophyll a and b is not exclusive to diatoms, as many other algae also possess these pigments, which are crucial for photosynthesis. The ability to survive in high salinity environments is not a distinguishing feature of diatoms, as many types of algae have adaptations that allow them to thrive in various salinity conditions. While rapid reproduction in freshwater can occur in different algal groups, it is not a unique feature of diatoms. Thus, the silica-containing cell walls are what specifically sets diatoms apart from other types of algae.