Benthic marine algae for assessing and monitoring coral reefs
Robert S. Steneck
University of Maine, Darling Marine Center, Walpole, ME, 04573, U.S.A.
Algal assemblages such as“crustose corallines”, “turfs” and “macroalgae” are good indicators of reef condition. Macroalgae are often deleterious to scleractinian corals and when at high biomass, reefs become degraded. Encrusting coralline algae are abundant in shallow heavily grazed zones and often indicate conditions favorable to reef development. Algal turfs are complex. Low canopy turfs devoid of sediment are abundant on reefs in good condition. High canopy, dense turfs that trap sediment can form occlusive mats that smother corallines and may impede settling corals.
I will review patterns of distribution and abundance of algal assemblages on Caribbean reefs relative to their environmental conditions. I will illustrate the talk with examples of natural and artificial experiments that demonstrate herbivore control of algal assemblages. Finally I will show how the Atlantic and Gulf Rapid Reef Assessment protocol (http://coral.aoml.noaa.gov/agra/) describes a rapid and efficient way to rapidly assess algal assemblages and major groups of herbivores.
