Tar Spot Algae
Mastocarpus spp./Ralfsia spp. and others
Description 2
These algae are dark brown to black crusts that grow on rocks. They are smooth or have prominent radial and concentric ridges. There are many nearly indistinguishable crust forms of several species of red and brown algae. Species of Ralfsia (brown algae) are nearly indistinguishable from the sporophyte crust of Mastocarpus spp. (red algae), so they are counted together, along with other less abundant species of encrusting red and brown algae, as tar spot algae for the purpose of LiMPETS monitoring.
References 3
Monterey Bay Aquarium Research Institute: Marine Botany
Abbott, I.A. and G.J. Hollenberg. 1976. Marine Algae of California. Stanford, University Press, Stanford, California.
Fun Fact 3
At least one “species” of Ralfsia is a growth form of an upright, thin blade-like brown algal species, Petalonia fascia. Whether it is a crust or blade may depend on temperature and photoperiod; warm temperature and long day lengths lead to the crust form. On the other hand, the tar-spot forms of Mastocarpus spp. are separate parts of the life cycle of those species, which are monitored as Stunted Turkish Towel algae by LiMPETS.
Sources and Credits
- (c) Cassie Milam, all rights reserved, uploaded by Cassie Milam
- Adapted by Cassie Milam from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Rhytisma_punctatum
- (c) Cassie Milam, some rights reserved (CC BY-SA)
