Macroalgae at Gray's Reef National Marine Sanctuary, Georgia

Abstract

Macroalgal assemblages were described from Gray's Reef National Marine Sanctuary (GRNMS), GA and compared to records from 25 years ago. For quantitative comparisons in species richness and biomass, divers collected algae from Searle's four northern sites and another four southern sites (n = six 400-cm2 quadrats per site). To compare species richness among sites, algae were also collected across limestone reefs at each site, and any new species were added to those recorded from the quadrat samples. Of the 55 species identified, 8 were new GRNMS records, 4 were new records to Georgia, and 36 had been recorded previously. Nine species were present at all of the 8 sites. Although species richness per site was significantly greater in southern GRNMS, biomass and species richness per 400 cm2 were similar between northern and southern sites. Sediment movement likely contributed to variability in species composition across the reefs.