reedman
Well-known member
Alright, I did a bit more research and I will retract several of my statements that Mike had rebuttals for. All of the images of reefs that I have seen have visible algae, but I guess they are all in decline (I was born too late to see the pristine reefs 
).
On the shrimps...I have no scientific evidence, but I have observed cleaner shrimp in tanks that appear much happier in a stand of macro algae than on the rocks.
I found the following info on a NOAA site:
Functional algal groups
Tropical reef algae can be divided into three key functional algal groups: crustose coralline algae, algal turfs, and macroalgae. Using a functional grouping approach is useful for understanding broader generalizations on the ecology of algae as well as predicting changes in algal community structure. Crustose coralline algae are often calcified, usually pink in color and adhere to the substrate; although some species have different characteristics. Algal turfs consist mostly of tiny filaments with canopy heights of less than 10 mm. Macroalgae are usually larger, canopy-formers, including brown algae (Dictyota, Sargassum), red algae (Gracilaria, Laurencia); green algae (Caulerpa, Microdictyon) and can be either fleshy (e.g., Lobophora) or calcareous (e.g., Halimeda).
Crustose coralline
Crustose corallines are calcified, often encrusting algae usually pink to dark burgundy in color (e.g., Porolithon, Peyssonnelia, Lithophyllum). Crustose coralline algae play two important roles in the coral reef community, first by contributing calcium carbonate to reef structure and second by possibly facilitating settlement of coral recruits. The ecology of crustose corallines is complex often interrelated with the presence of macro and turf algae, grazing intensity by herbivores, and productivity.
Turf algae
Turf algae are a multispecific assemblage of diminutive, often filamentous, algae that attain a canopy height of only 1 to 10 mm (see Steneck 1988 for review). These microalgal species have a high diversity (>100 species in western Atlantic), although only 30 to 50 species commonly occur at one time. There is a high turnover of individual turf algal species seasonally and only a few species are able to persist or remain abundant throughout the year. But turf algae, when observed as a functional group, remain relatively stable year round (Steneck and Dethier 1994). They are often able to recovery rapidly after being partially consumed by herbivores. Turfs are capable of trapping ambient sediment and kill corals by gradual encroachment.
Macroalgae
Macroalgae are larger (canopy height usually >10mm) erect algae often with anatomically complex forms. Most macroalgae possess some from of deterrent against herbivory, either through chemical deterrents or structural resistance. Although macroalgae are often more resistant to physical and biological disturbances than corallines and turfs, grazing by certain herbivores and high wave action can inhibit macroalgal growth. High macroalgal biomass can interfere with coral recruitment and reduce coral survival.
). On the shrimps...I have no scientific evidence, but I have observed cleaner shrimp in tanks that appear much happier in a stand of macro algae than on the rocks.
I agree. I would never use macros as an export because I wouldn't want the maintainence. I was thinking purely of a natural food source. Many fishes naturally graze, and providing an alternate food source that allows grazing might be difficult.
I found the following info on a NOAA site:
Functional algal groups
Tropical reef algae can be divided into three key functional algal groups: crustose coralline algae, algal turfs, and macroalgae. Using a functional grouping approach is useful for understanding broader generalizations on the ecology of algae as well as predicting changes in algal community structure. Crustose coralline algae are often calcified, usually pink in color and adhere to the substrate; although some species have different characteristics. Algal turfs consist mostly of tiny filaments with canopy heights of less than 10 mm. Macroalgae are usually larger, canopy-formers, including brown algae (Dictyota, Sargassum), red algae (Gracilaria, Laurencia); green algae (Caulerpa, Microdictyon) and can be either fleshy (e.g., Lobophora) or calcareous (e.g., Halimeda).
Crustose coralline
Crustose corallines are calcified, often encrusting algae usually pink to dark burgundy in color (e.g., Porolithon, Peyssonnelia, Lithophyllum). Crustose coralline algae play two important roles in the coral reef community, first by contributing calcium carbonate to reef structure and second by possibly facilitating settlement of coral recruits. The ecology of crustose corallines is complex often interrelated with the presence of macro and turf algae, grazing intensity by herbivores, and productivity.
Turf algae
Turf algae are a multispecific assemblage of diminutive, often filamentous, algae that attain a canopy height of only 1 to 10 mm (see Steneck 1988 for review). These microalgal species have a high diversity (>100 species in western Atlantic), although only 30 to 50 species commonly occur at one time. There is a high turnover of individual turf algal species seasonally and only a few species are able to persist or remain abundant throughout the year. But turf algae, when observed as a functional group, remain relatively stable year round (Steneck and Dethier 1994). They are often able to recovery rapidly after being partially consumed by herbivores. Turfs are capable of trapping ambient sediment and kill corals by gradual encroachment.
Macroalgae
Macroalgae are larger (canopy height usually >10mm) erect algae often with anatomically complex forms. Most macroalgae possess some from of deterrent against herbivory, either through chemical deterrents or structural resistance. Although macroalgae are often more resistant to physical and biological disturbances than corallines and turfs, grazing by certain herbivores and high wave action can inhibit macroalgal growth. High macroalgal biomass can interfere with coral recruitment and reduce coral survival.
