Drake, L. A. Old Dominion University, ldrake@odu.edu
Zimmerman, R. C. Moss Landing Marine Laboratories, RZimmer197@aol.com
Cummings, M. E. University of California at Santa Barbara, cummings@lifesci.ucsb.edu
Dobbs, F. C. Old Dominion University, fdobbs@odu.edu

 
EPIPHYTE LOAD ON SEAGRASS LEAVES: EFFECTS OF LEAF AGE AND INFLUENCE ON INHERENT OPTICAL PROPERTIES
 
Epiphytes play a critical role in seagrass ecosystems, providing as much as 50 percent of the primary production in healthy environments. Eutrophication, however, can cause overgrowth and smothering of seagrasses by epiphytes. This study quantified the abundance of epiphytes growing on leaves of Thalassia testudinum (turtlegrass) at Lee Stocking Island, Bahamas, and measured the inherent optical properties of the intact epiphyte biofilm on turtlegrass leaves. Differences in epiphyte load were determined quantitatively by removing the epiphytes and measuring their lipid biomass. Qualitative characterization of the colonizing organisms was performed using scanning electron microscopy. Each method indicated an increase in epiphyte biomass with increasing age of the leaves. Likewise, light absorption and backscattering of the epiphyte layer were determined spectrophotometrically on intact leaves. Those data were incorporated into a model that can predict the biomass-dependent light attenuation of the epiphyte community and its impact on light-dependent photosynthesis of seagrass leaves. These results are useful for determining quantitative and qualitative impacts of epiphyte loading on the photosynthetic performance of seagrass leaves. This investigation was sponsored by the Office of Naval Research, Coastal Benthic Optical Properties (CoBOP) program.
 
Day: Tuesday, Feb. 2
Time:
Location: Sweeney Center
 
Code: SS17TU0308S