Characterization of Macroalgal Epiphytes on Thalassia Testudinum in Tampa Bay, Florida

Blooms of seagrass epiphytes have potentially important economic and ecological consequences in Tampa Bay, one of the Gulf of Mexico's largest estuaries. As part of a Tampa Bay pilot study to monitor the impact of environmental stresses, precise characterization of epiphyte diversity is required for efficient management of affected resources, and thus may be used as a rational basis for assessment of ecosystem health. Fixed monitoring sites were selected north of Port Manatee, composed of dense and sparse Thalassia testudinum seagrass sites. A total of 13 epiphytic species encompassing green, brown and red macroalgae were manually collected in May 2001 from dense seagrass beds versus nine species from sparse beds. Epiphytes only collected in the dense beds were Enteromorpha flexuosa, Sphacelaria rigidula, Ceramium byssoideum, and Herposiphonia tenella; epiphytes only occurring in the sparse beds were Griffithsia and Stylonema alsidii. A correlation seems to emerge among attachment mode of epiphyte to host, presence of cortication and epiphyte length. A main goal of this ongoing study is the determination of indicator species for both healthy and stressed seagrass bed environments using both taxonomic and gene‐sequencing techniques.