Fringing reefs

Abstract

Fringing reefs are shore-attached and are exposed to a variety of pressures and processes related to this association that can affect their development. Although most fringing reefs are morphologically simple, their morphologies may become more complex where they incorporate reef flats formed at higher mid-Holocene sea levels, and where terrestrial inputs and processes affect them. The apparent geomorphological simplicity of many fringing reefs masks development histories and internal structures that can be complex and diverse – fringing reefs develop over a range of foundations and are constructed of a variety of materials deposited in numerous arrangements (Figure 5). Of course, reefs are three-dimensional structures, and structural variation may occur within a single fringing reef. Although geographical variation exists due to differences in Holocene sea-level history and substrate availability, most fringing reefs experienced a period of active growth from 7,000 to 5,000 years ago when they produced most of their structure. On many fringing reefs living coral is now restricted to a narrow band near the seaward reef edge.