Poster: Ecophysiology

Abs # 56: Photosynthesis - nitrogen relationship in five Hawaiian reef algae

Presenter:	Iriondo, Maya , simek@hawaii.edu
Authors	Iriondo, Maya  (A)   Smith, C. M.  (A)
Affiliations:	(A): Dept. of Botany, University of Hawaii at Manoa

The relationship between photosynthetic capacity (P_max) and total tissue nitrogen contents was examined in five taxonomically unrelated species of marine algae – two brown, two red, and one nitrogen-fixing cyanophyte - that are common on Hawaiian reefs. There was a positive linear relationship between tissue N contents and P_max for all five species examined. The cyanophyte showed the highest values of P_max, followed by the two brown, and red algae, respectively. However, the two brown species had the highest nitrogen use efficiency (P _max / total tissue nitrogen), followed by the blue-green and red alga, respectively. In a nitrogen-limited environment, plants with higher nitrogen use efficiency may have a competitive advantage over their neighbors. The relatively lower nitrogen use efficiency of the blue-green alga could be associated to its capacity to fix nitrogen.