from terrestrial sources such as freshwater runoff resulting in
elevated nutrient levels. This is particularly pronounced when the land is heavily forested. Islands or coastlines that are drier tend to show reef formations more like those found on oceanic reefs. Both stony and soft coral diversity tends to be lower on near-shore reefs
Intertidal mudflats
Along the coastline, one can often find extensive mangrove beds. These areas are home to many of the juvenile forms of creatures found on the nearby reef. It is not unusual to find some stony corals in this area as well, particularly Pocillopora spp., growing on the roots of the mangroves (Veron, 1986). As one moves seaward the water increases in depth, and coral cover begins to increase. Seagrasses may be encountered growing with the corals. Corals found in this area include Catalapbyllia, Goniopora, Euphyllia, Montipora and certain Acropora spp.
Sand Flats
Between the seagrass bed and the outer slope a broad sandy area may exist. In this area several mixed coral communities may occur composed of Acropora, Favia, Favites, Galaxea, Goniastrea, Platygyra, Plerogyra, Pocillopora, and Pontes. Soft corals include Heliopora, Lobopbytum, Sarcophyton and Sinularia, but Xenia and Cespitulana tend to be die most common soft coral genera (Dinesen, 1983).
Outer Slope
Near the upper edge of the reef one finds low encrusting corals, mostly Acropora, Pocillopora, and Millepora. Tubipora, Heliopora, Lobopbytum, Sarcophyton, Sinularia,, and Xenia are common soft corals in this zone, and the zoanthid Palytboa is also abundant here (Stoddart, 1973).
As the water deepens, the reef slopes down towrards the sea floor, which may be only 10 m (33 ft.) deep in some cases (Veron, 1986). These slopes usually have a wide variety of stony and soft corals, but few Acropora species are present. Most other stony coral genera are found, with Goniopora,, Pavona, Pontes, and Turbinaria being the most dominant (Veron, 1986). Free-living fungiids are not uncommon in cleaner waters and many shelf-forming species occur i.e. Turbinaria, Fcbinopora, and Montipora (Veron, 1986). Many of the corals collected for the aquarium trade occur in this region.
Acropora sp. with Green Chromis and Butterfly fish on back-reef flat, Fiji. B. Carlson.
Lagoon in New Guinea. S. W. Michael.
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Green water turbid lagoon at 12 m (40 ft.) in Palau. Pavona, Plerogyra, and Lobophyllia visible. B. Carlson.
Figure 1.1 Barrier Reef
Beach
Sand Flat
Fringing Reel
Lagoon
Fore Reef Slope Spur & Groove
Beach
Sand Flat
Fringing Reel
Lagoon
Fore Reef Slope Spur & Groove
Reef Flat
Back Reef Slope
Figure 1.2 Fringing Reef
Reef Flat
Back Reef Slope
Figure 1.2 Fringing Reef
Beach Back Reef Margin
Patch Reef Sand Flat
Lagoon Reef Flat
Spur & Groove Reef Crest Fore Reef Slope
Beach Back Reef Margin
Patch Reef Sand Flat
Lagoon Reef Flat
Spur & Groove Reef Crest Fore Reef Slope
Figure 1.3 Atoll Reef
Fringing Reef Outer Lagoon
Lagoon -
Reef Face Island with Sand Bank
Fringing Reef Outer Lagoon
Lagoon -
Reef Face Island with Sand Bank
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