reefal

Reefal refers to coral reef–dominated communities and the carbonate frameworks they build. The term is used in modern reef ecology and in paleoecology to distinguish reef-building assemblages from non-reefal marine communities. In living systems, reefals form the physical backbone of coral reef ecosystems; in the fossil record, reefal facies are limestone rocks that record ancient reef structures.

Key features of reefal systems include a calcium carbonate framework produced primarily by scleractinian corals, often with contributions from coralline algae, bryozoans, and other calcifying organisms. This framework creates a three‑dimensional habitat that supports a diverse array of fishes, invertebrates, and algae. Structural complexity influences local hydrodynamics, sediment retention, and nutrient cycling. Growth and persistence depend on adequate light, suitable temperatures, stable salinity, and appropriate wave energy; substantial disturbances can reduce live coral cover and slow or reverse framework accretion.

Geographically, reefals occur in shallow, sunlit tropical and subtropical seas where seawater chemistry permits calcification. Typical reefal environments display vertical zonation, including crest, fore-reef slope, and back-reef zones, each hosting characteristic communities.

Ecological importance and threats: reefals provide habitat complexity, support high biodiversity, and offer ecosystem services such as fisheries, coastal protection, and tourism. They are sensitive to climate change and ocean acidification, which can impair calcification and lead to structural decline. Local stressors—overfishing, pollution, and sedimentation—can compound global pressures. Conservation and management efforts, including marine protected areas and restoration projects, aim to promote resilience and slow reefal degradation.