climate (e.g., Blanchon et al., 1997; Braithwaite et al.,
2000) (see Tropical Cyclone/Hurricane). These factors
combine to produce fringing reefs that may on the surface
appear simple (as described by Stoddart and Steers, 1977),
but which morphostratigraphic and geochronological
investigations of a broad sample of fringing reefs from
around the world show may be produced by a variety of
different growth models. The aims of this short review
are to examine the main factors that control fringing reef
development in its various modes and to describe the main
features common to most fringing reefs.
Fringing reefs and terrestrial influence
By definition fringing reefs are closely associated with
adjacent landmasses. These landmasses fundamentally
influence fringing reef development by providing the
substrate on which most develop. Another consequence
of this relationship is, however, that fringing reefs are
more directly exposed to freshwater, nutrients, and sediments – natural and anthropogenic – shed from coastal
catchments, which may inhibit coral growth (e.g., Cortes
et al., 1994; Furnas, 2003; McCulloch et al., 2003;
Fabricius, 2005) and influence reef development (e.g.,
Bellwood et al., 2004). The nature of these interactions
is outlined below.
Fringing reef substrates
Many fringing reefs do grow over rocky substrates as
suggested in classic models of fringing reef development.
In mid-ocean settings, drilling (see Drilling) through the
entire reef sequence has, for example, established volcanic
foundations for the fringing reef at Hanauma Bay, Oahu,
Hawaii (Easton and Olson, 1976) and at Pointe-au-Sable
Reef, Mauritius (Montaggioni and Faure, 1997). On high
islands and mainland coasts bedrock foundations for
fringing reefs have similarly been established (e.g., at the
north and northeastern end of Grand Terre, New
Caledonia [Cabioch et al., 1999], at Phuket [Scoffin and
Le Tissier, 1998], and at Punta Islotes, Costa Rica [Cortes
et al., 1994]). The suitability of these stable substrates for
coral colonization and reef growth is demonstrated by the
rapidity with which reefs form on recent volcanic islands;
Umbgrove (1930) described incipient fringing reef growth
at Krakatoa less than 50 years after its catastrophic eruption (see Volcanic Disturbances and Coral Reefs).
Although rock substrates are widely perceived as optimal
for reef initiation and growth due to their stability and elevation above the sea floor (Veron, 1995), on the GBR
where more than 25 fringing reefs have been cored – only
at Scawfell Island on the southern GBR is the possibility
of a bedrock foundation suggested, despite the widespread
availability of headlands (Kleypas, 1991).
As additional coring data from fringing reefs have
become available it is evermore apparent that fringing
reefs can rise from a variety of foundations. Although
fringing reefs less commonly develop over Last Interglacial (LIG) or older reefs (see Last Interglacial and Reef
Development) than barrier reefs or atolls, drilling
has confirmed a pre-Holocene reefal basement for many
fringing reefs including Australia’s largest fringing reef –
Ningaloo Reef, Western Australia (Collins et al., 2004),
fringing reefs in the Ryukyu Islands of Japan (Kan et al.,
1995; Webster et al., 1998), those on the south and southwestern shores of Grande Terre, New Caledonia (Cabioch
et al., 1999), and for many fringing reefs throughout the
Caribbean (e.g., Milliman, 1973; Hubbard et al., 2005).
Different carbonate deposits of varying age underlie other
fringing reefs, including Miocene calcareous siltstones at
Galeta Point, Panama (Macintyre and Glynn, 1976), and
eolianites at Lord Howe Island (Woodroffe et al., 2005)
(see Eolianite).
The occurrence of unconsolidated sediments, often
very fine, on the seafloor in nearshore environments is
not unexpected given the proximity to fluvial and other
sources. However, the frequency with which fringing reefs
have grown over these foundations is more surprising
given the difficulties that such substrates present for coral
settlement and growth (see Corals: Environmental Controls on Growth). Nonetheless cores through many Holocene fringing reef sequences terminate in either
Holocene siliciclastic deposits, sometimes mixed with
reefal carbonates (Perry, 2003; Perry and Smithers,
2006), or in Pleistocene clays (Hopley et al., 1983; Perry
and Smithers, 2010). In several instances fringing reefs
have established on deltaic deposits of alluvial cobbles
(Partain and Hopley, 1989) where fluvial discharge of
water and sediments have clearly in the past been significant (see Turbid Zone and Terrigenous SedimentInfluenced Reefs), and at others Pleistocene boulder
beaches appear to have been colonized by reefs in the
Holocene (Hopley and Barnes, 1985; Perry and Smithers,
2009) (see Boulder Beaches).
The topography and spatial extent of the substrate can
exert considerable influence on fringing reef morphology
and geometry (Davies and Marshall, 1979), although the
effects of both usually diminish with time (Macintyre
and Glynn, 1976). At the most basic, on steep shorelines
the extent to which the fringing reef may prograde seaward is limited by the depth of the foundations so that
typically narrow reefs develop – vigorous reef growth is
restricted to within 50 m or so of the surface (see Corals:
Environmental Controls on Growth). In contrast, where
the substrate is more gently sloping, the reef may construct
a broad reef flat extending hundreds of meters offshore. As
discussed in section “Fringing reef structure and growth
models,” particularly on shallow gradient substrates fringing reefs may grow in complex ways and diverge significantly from the Darwin’s classic simple model of
seaward progradation from the shore. On more gently
sloping coasts fringing reefs may initiate over
a relatively broad area if suitable substrate is available,
so that a diffuse “incipient reef ” comprised initially of
separate patch reefs may coalesce to form a more substantial fringing reef structure (Figure 1b). Chappell et al.
(1983) suggested these models could accommodate many
fringing reefs of the GBR, but they clearly have wider
432
FRINGING REEFS
2000) (see Tropical Cyclone/Hurricane). These factors
combine to produce fringing reefs that may on the surface
appear simple (as described by Stoddart and Steers, 1977),
but which morphostratigraphic and geochronological
investigations of a broad sample of fringing reefs from
around the world show may be produced by a variety of
different growth models. The aims of this short review
are to examine the main factors that control fringing reef
development in its various modes and to describe the main
features common to most fringing reefs.
Fringing reefs and terrestrial influence
By definition fringing reefs are closely associated with
adjacent landmasses. These landmasses fundamentally
influence fringing reef development by providing the
substrate on which most develop. Another consequence
of this relationship is, however, that fringing reefs are
more directly exposed to freshwater, nutrients, and sediments – natural and anthropogenic – shed from coastal
catchments, which may inhibit coral growth (e.g., Cortes
et al., 1994; Furnas, 2003; McCulloch et al., 2003;
Fabricius, 2005) and influence reef development (e.g.,
Bellwood et al., 2004). The nature of these interactions
is outlined below.
Fringing reef substrates
Many fringing reefs do grow over rocky substrates as
suggested in classic models of fringing reef development.
In mid-ocean settings, drilling (see Drilling) through the
entire reef sequence has, for example, established volcanic
foundations for the fringing reef at Hanauma Bay, Oahu,
Hawaii (Easton and Olson, 1976) and at Pointe-au-Sable
Reef, Mauritius (Montaggioni and Faure, 1997). On high
islands and mainland coasts bedrock foundations for
fringing reefs have similarly been established (e.g., at the
north and northeastern end of Grand Terre, New
Caledonia [Cabioch et al., 1999], at Phuket [Scoffin and
Le Tissier, 1998], and at Punta Islotes, Costa Rica [Cortes
et al., 1994]). The suitability of these stable substrates for
coral colonization and reef growth is demonstrated by the
rapidity with which reefs form on recent volcanic islands;
Umbgrove (1930) described incipient fringing reef growth
at Krakatoa less than 50 years after its catastrophic eruption (see Volcanic Disturbances and Coral Reefs).
Although rock substrates are widely perceived as optimal
for reef initiation and growth due to their stability and elevation above the sea floor (Veron, 1995), on the GBR
where more than 25 fringing reefs have been cored – only
at Scawfell Island on the southern GBR is the possibility
of a bedrock foundation suggested, despite the widespread
availability of headlands (Kleypas, 1991).
As additional coring data from fringing reefs have
become available it is evermore apparent that fringing
reefs can rise from a variety of foundations. Although
fringing reefs less commonly develop over Last Interglacial (LIG) or older reefs (see Last Interglacial and Reef
Development) than barrier reefs or atolls, drilling
has confirmed a pre-Holocene reefal basement for many
fringing reefs including Australia’s largest fringing reef –
Ningaloo Reef, Western Australia (Collins et al., 2004),
fringing reefs in the Ryukyu Islands of Japan (Kan et al.,
1995; Webster et al., 1998), those on the south and southwestern shores of Grande Terre, New Caledonia (Cabioch
et al., 1999), and for many fringing reefs throughout the
Caribbean (e.g., Milliman, 1973; Hubbard et al., 2005).
Different carbonate deposits of varying age underlie other
fringing reefs, including Miocene calcareous siltstones at
Galeta Point, Panama (Macintyre and Glynn, 1976), and
eolianites at Lord Howe Island (Woodroffe et al., 2005)
(see Eolianite).
The occurrence of unconsolidated sediments, often
very fine, on the seafloor in nearshore environments is
not unexpected given the proximity to fluvial and other
sources. However, the frequency with which fringing reefs
have grown over these foundations is more surprising
given the difficulties that such substrates present for coral
settlement and growth (see Corals: Environmental Controls on Growth). Nonetheless cores through many Holocene fringing reef sequences terminate in either
Holocene siliciclastic deposits, sometimes mixed with
reefal carbonates (Perry, 2003; Perry and Smithers,
2006), or in Pleistocene clays (Hopley et al., 1983; Perry
and Smithers, 2010). In several instances fringing reefs
have established on deltaic deposits of alluvial cobbles
(Partain and Hopley, 1989) where fluvial discharge of
water and sediments have clearly in the past been significant (see Turbid Zone and Terrigenous SedimentInfluenced Reefs), and at others Pleistocene boulder
beaches appear to have been colonized by reefs in the
Holocene (Hopley and Barnes, 1985; Perry and Smithers,
2009) (see Boulder Beaches).
The topography and spatial extent of the substrate can
exert considerable influence on fringing reef morphology
and geometry (Davies and Marshall, 1979), although the
effects of both usually diminish with time (Macintyre
and Glynn, 1976). At the most basic, on steep shorelines
the extent to which the fringing reef may prograde seaward is limited by the depth of the foundations so that
typically narrow reefs develop – vigorous reef growth is
restricted to within 50 m or so of the surface (see Corals:
Environmental Controls on Growth). In contrast, where
the substrate is more gently sloping, the reef may construct
a broad reef flat extending hundreds of meters offshore. As
discussed in section “Fringing reef structure and growth
models,” particularly on shallow gradient substrates fringing reefs may grow in complex ways and diverge significantly from the Darwin’s classic simple model of
seaward progradation from the shore. On more gently
sloping coasts fringing reefs may initiate over
a relatively broad area if suitable substrate is available,
so that a diffuse “incipient reef ” comprised initially of
separate patch reefs may coalesce to form a more substantial fringing reef structure (Figure 1b). Chappell et al.
(1983) suggested these models could accommodate many
fringing reefs of the GBR, but they clearly have wider
432
FRINGING REEFS