- Kingdom: Plantae
- Phylum: Rhodophyta
- Norwegian: rødalger
There are 7000, mainly marine, species in the world. Approximately 220 different red algae, in a addition to a few fresh-water species, are known from Norwegian waters. Many of them prefer temperate waters, and have a northern distribution limit somewhere along the coast of Norway.
The red color is produced by certain light-absorbing proteins that works in conjunction with the chlorophyll. The red algae come in a wide range of appearances. Some "chalky reds" forms calcareous sheets, nodules or branched structures. Others are branched and shaped like fans, feathers or more irregular structures. They live from the tidal zone and as deep as 250 meters, deeper than any green or brown algae.