XVI International Botanical Congess

A one-year study conducted in 1998 investigated macroalgal species composition, distribution and abundance at seven littoral zone sites in the lower St. Johns River. Macroalgal community structure and biomass varied seasonally and spatially, both between beds of submerged aquatic vegetation (SAV)and within individual SAV beds. Dominant macroalgae included Lyngbya wollei, Enteromorpha sp., Oedogonium spp. and Rhizoclonium sp. Both presence/absence and species composition of SAV were important factors in the distribution of macroalgae within a bed. Relationships between important water quality variables and macroalgal distribution and biomass will also be discussed.