Odonthalia washingtoniensis Kylin

Type locality: Cattle Point, San Juan Island, WA

Etymology: Odonthalia (Greek= toothed branch) washingtoniensis (from Washington state)

Common name: Sea brush

1. Taxonomy

Florideophyceae: Rhodymeniophycidae: Ceramiales: Rhodomelaceae


Fig. 1. Odontalia washingtoniensis in the intertidal of Eagle Cove. Scale bar= 2 cm.

2. Identification.

Odonthalia species are mostly freely branched, having a distinctive bushy appearance. Some species may be partially flattened. The branch tis are sharp and often tightly clustered. Their color ranges from brown to dark red to almost black. In tide pools and the mid-and lower intertidal regions, these plants take on a bewildering range of morphologies. However, the clustering of sharp-tipped braches seems consistent for the group. Mature plants may be small, from a few cm long to 50 cm long (Druehl, 1936).


3. Distribution.

North America: Alaska (Lindstrom 1977, Scagel et al. 1989), British Columbia (Scagel et al. 1989), California (Abbott & Hollenberg 1976, Scagel et al. 1989, Miller 2012), Oregon (Hansen 1997, Zuccarello, Moon & Goff 2004), Washington (Scagel et al. 1989, Murru & Sandgren 2004).

Regional Distribution (based on FHL Herbarium Collection): Salmon bank, San Juan Island, dredged, 1904, 1947, 1953, 1963, 1965 and 1969; Partridge bank, Whidbey Island, 1966; Davis Bay, 1925; Hein Bank, San Juan Island, dredged, 1964; Cattle Point, intertidal, 1964 and 1966; Between American Camp and Eagle Cove, intertidal, 1966; Whiffin Spit, Vancouver Island, 1989.

4. Vouchers.

Herbarium species housed at FHL Herbarium (under the PHYKOS number 00144).

5. Research Notes. 

This species was firstly described in the publication “The marine red algae in the vicinity of the Biological Station at Friday Harbor”, by Kylin (1925), and therefore the type locality is very closer to the site we found this specimen (fig. 1). When observed at low tide on moderate wave-exposed shores, Odonthalia forms dense mats, which when parted are seen to cover an array of less conspicuous plnt and animal life. The matted plants also house many zooplankton (floating animals). These small animals may use the seaweed mat for protection from drying during times of low tide or they may live in the mat, acquriring theis food from the microscopic plant living attached to Odontalia. Tomar Probyn and Tony Chapman, Dalhouse Unversity researchers, described a potentially mutualistic association between zooplankton and a bushy brown seaweed whereby the seaweed-inhabiting zooplankton nurture the plants with their excrement when nutrients are seasonally poor, thereby enhancing their home (Druehl, 1936).

Bromophenols isolated from the red alga Odonthalia were tested as a ICL (grisea isocitrate lyase) inhibitory activity, which is a key enzyme in the glyoxylate cycle, and is highly expressed during appressorium-mediated plant infection by fungal pathogen, and the data suggest that bromophenols have protective effects and act as a strong inhibitior of appressorium formation on rice plants (Lee et al. 2007).

An important ecological study on Odonthalia about the epiphyte-host interactions between this genus and the diatom Isthmia nervosa have revealed that negative effects of epiphytism  were retricted to physiologically individual, but not at population level. Spatial heterogeneity and food web complexity may attenuate the signal of epiphyte effects from individual to population levels. Because of the seasonal breakage colonization of Odonthalia after tetraspore development, and changes in this timing could affect community dynamics.

6. Literature Cited.

Druehl, L. D. 1936. Pacific seaweeds : a guide to common seaweeds of the West Coast.

Kylin, H. (1925). The marine red algae in the vicinity of of the Biological Station at Friday Harbor, Wash. Lunds Universitets Årsskrift, Ny Följd, Andra Afdelningen21(9): 1-87.

Lee, H., Lee, T., Lee, J. H.,  Chae, C., Chung, S., Shin, D., Shin, J. & Oh, K. 2007. Inhibition of the Pathogenicity of Magnaporthe grisea by Bromophenols, Isocitrate Lyase Inhibitors, from the Red Alga Odonthalia corymbifera. J. Agric. Food Chem. 2007, 55, 6923−6928.

7. Links to additional resources.

For molecular data available: http://www.ncbi.nlm.nih.gov/nuccore/?term=Odonthalia%20washingtoniensis

More informations about Florideophyceae: http://tolweb.org/Florideophyceae

More informations about Rhodomelaceae: http://tolweb.org/Rhodomelaceae/23531

8. Page Authors & Affiliations.

Talita Vieira-Pinto, Ph.D. student, Instituto de Biociências, Universidade de São Paulo. Rua do Matão, travessa 14, nº 321, Cidade Universitária, São Paulo – SP, Brazil.