LIMPETS: Long-term Monitoring Program and Experiential Training for Students

Student Scientists on our Sanctuary Shores

Species

Algae

Identifying algae is not always easy! Learn more about the algae monitored by the LiMPETS program. The list below includes:

  • 16 core taxa that are monitored at as many sites as possible
  • 3 other taxa (denoted with *) that are monitored at only one or two sites

Go to Datasheets and Forms to find out which species are monitored at your LiMPETS site of interest.

Tar Spot Algae (Mastocarpus spp./Ralfsia spp. and others)
Description:
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.
Distribution:
Alaska to Mexico.
Habitat:
Common on rocks throughout the intertidal.
Diet:
Sunlight and dissolved nutrients, which are required for photosynthesis.
Fun Fact:
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 depends 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.
Reason for Monitoring:
These encrusting forms are resistant to grazing, trampling, and pollution and can be the dominant species on primary substrate.
References:
Monterey Bay Aquarium Research Institute: Marine Botany
Abbott, I.A. and G.J. Hollenberg. 1976. Marine Algae of California. Stanford, University Press, Stanford, California.