Zone Types

Thirteen mutually exclusive zones were identified from land to open water corresponding to typical insular shelf and coral reef geomorphology (Fig. 1-3). These zones include: shoreline intertidal, vertical wall, lagoon, back reef, reef flat, reef crest, fore reef, bank/shelf, bank/shelf escarpment, channel, dredged (since this condition eliminates natural geomorphology), unknown, and land. Zone refers only to each benthic community's location and does not address substrate or cover types within. For example, the lagoon zone may include patch reefs, sand, and seagrass beds; however, these are considered structural elements that may or may not occur within the lagoon zone and therefore, are not used to define it.

Figure 1. Barrier reef cross-section. Reef separated from the shore by a relatively wide, deep lagoon.

Figure 2. Fringing reef cross-section. Reef platform is continuous with the shore.

Figure 3. Atoll cross-section. Reef surrounding a lagoon.