Publication Date

Fall 2014

Degree Type


Degree Name

Master of Science (MS)


Moss Landing Marine Laboratories


Michael H. Graham


Calliarthron, Monterey Peninsula, phenotypic variation

Subject Areas



Coralline algae are ubiquitous in near-shore marine environments. In particular, geniculate corallines occur in intertidal and subtidal habitats with abundances typically higher at shallow depths. Due to the high abundance of Calliarthron tuberculosum in Monterey kelp beds, this species was chosen to study effects of depth, site, and season on morphology and physiology. To further understand this pattern, populations from 3 and 10 m depth were sampled at two sites to examine morphometric variables including total length, total width, and number of branch tips as well as, physiological variables including respiration, photosynthetic, and calcification rates. Growth rates were also quantified spatially and temporally. The number of branch tips found on shallow individuals was double that of the individuals found at deeper depths while there were no apparent differences in total length and total width with depth. Physiological variables differed but generally were higher in shallow individuals and greater during winter months. There was a depth effect found for growth with shallow individuals generally growing faster than deep individuals. The density of branch tips may facilitate coralline dominance at shallower depths and have implications on the ecology of these near-shore environments.