Chrysolaminarin is a storage polysaccharide typically found in photosynthetic heterokonts.

It is used as a carbohydrate food reserve by phytoplankton such as Bacillariophyta (similar to the use of laminarin by brown algae).

In addition, heterokont algae use oil as a storage compound.

Besides energy reserve, oil helps the algae to control their buoyancy.

[4] Chrysolaminarin is also the major storage polysaccharide of most haptophyte algae.