Chaetoceros is a genus of diatoms where cells are interconnected to create extended chains. These individual cells appear elliptical to circular when viewed from the valve, which classifies them as centric diatoms. In girdle view, they take on a rectangular shape. Similar to other diatoms, Chaetoceros cells are encased in siliceous cell walls known as frustules. Each frustule includes four hollow structures known as setae or spines, which facilitate the connection of adjacent cells to form colonies. These colonies can adopt various shapes, such as coiled, straight, or curved chains. The size of these cells can vary, spanning from less than 10 micrometers to 50 micrometers. Certain Chaetoceros species can produce robust resting spores that are exceptionally resilient in challenging environmental conditions.