Turf and encrusting algae
Turf algae and encrusting coralline algae occur throughout Cook Island Aquatic Reserve.
Turf algae dominate shallow areas of bedrock and boulder habitat, as well as deeper areas (>10 m) where there is a suitable place to attach and grow.
While less abundant, patches of encrusting coralline algae can be seen on rocks among the turfing algae.
Crustose coralline algae have a strong influence on the composition of marine sediment in the aquatic reserve, contributing calcium carbonate (limestone or chalk) to the sand as they decompose.
Marine life
Turf algae provide habitat for microscopic invertebrates, which are preyed upon by many species including dwarf hawkfish and leatherjackets.
Some herbivores, like sea urchins and some snails, also feed directly on the algae, rasping it off the rocks.
Coral rockcod, eastern pomfred and blacktip bullseye swimming above
turf and encrusting algae and orange-spouted seasquirts
(Photo: Gary Shuttleworth)
Dwarf hawkfish live on the reef, and feed on tiny crustaceans found among the turfing algae (Photo: Ecological Service Professionals)
Kuiter’s nudibranch searching through turfing and articulate coralline algae for sponges to eat (Photo: Ecological Service Professionals)
Lamington (left) and collector (right) sea urchins grazing on turfing algae while decorated with foliose macroalgae (Photo: Ecological Service Professionals)
Juvenile blue angelfish feeding on turf and encrusting algae amongst boulders (Photo: Gary Shuttleworth)
Eastern blue groper visiting a cleaning station, with common cleaner fish, amongst boulders in turf and encrusting algae (Photo: Gary Shuttleworth)
Papua scorpionfish (Scorpaenopsis papuensis) in turf and encrusting algae habitat (some hard corals) (Photo: Rudi Vir)
Gloomy nudibranch (Tambja morosa) in turf and encrusting algae habitat (Photo: Rudi Vir)
Obscure nudibranch (Hypselodoris obscura) in turf and encrusting algae habitat (Photo: Rudi Vir)
Day octopus sliding across turf algae (Photo: Gary Shuttleworth)
