cyclone impacts (see Tropical Cyclone/Hurricane). It has
been argued that rates of sea level rise of $0.5 m by AD
2100 might create new accommodation space and switch
reef vertical accretion back on, with carbonate production
for the entire Great Barrier Reef rising from the current estimated 50 Mt a
À1 to 70 Mt a
À1 (Kinsey and Hopley, 1991).
Bibliography
Cowell, P. J., and Thom, B. G., 1994. Morphodynamics of coastal
evolution. In Carter, R. W. G., and Woodroffe, C. D., (eds.),
Coastal Evolution: late Quaternary shoreline morphodynamics.
Cambridge: Cambridge University Press, pp. 33–86.
Cowell, P. J., and Kench, P. S., 2002. The morphological response
of atoll islands to sea-level rise. Part 1: modifications to the
shoreface translation model. Journal of Coastal Research, ICS
2000, 633–644.
Gray, S. C., Hein, J. R., Hausmann, R., and Radtke, U., 1992. Geochronology and subsurface stratigraphy of Pukapuka and
Rakahanga atolls, Cook Islands: Late Quaternary reef growth
and sea level history. Palaeogeography, Palaeoclimatology,
Palaeoecology, 91, 377–394.
Grigg, R. W., 1998. Holocene coral reef accretion in Hawaii: a function
of wave exposure and sea level history. Coral Reefs, 17, 263–272.
Kennedy, D. M., and Woodroffe, C. D., 2002. Fringing reef growth
and morphology: a review. Earth Science Reviews, 57, 255–277.
Kinsey, D. W., and Hopley, D., 1991. The significance of coral reefs as
global carbon sinks – response to greenhouse. Palaeogeography,
Palaeoclimatology, Palaeoecology, 89, 363–377.
Quinn, T. M., and Matthews, R. K., 1990. Post-Miocene diagenetic
and eustatic history of Enewetak Atoll: Model and data comparison. Geology, 18, 942–945.
Smithers, S. G., Hopley, D., and Parnell, K. E., 2006. Fringing and
nearshore coral reefs of the Great Barrier Reef: episodic Holocene development and future prospects. Journal of Coastal
Research, 22, 175–187.
ACROPORA
Carden C. Wallace
Museum of Tropical Queensland, Townsville, QLD,
Australia
Synonyms
Arborescent corals; Axial branching corals; Midori ishi
(Japan); Staghorn corals; Table corals
Definition
Acropora (Oken, 1815) is the type genus of the hard coral
family Acroporidae (class Anthozoa, order Scleractinia
of the phylum Cnidaria). Currently, around 120–140 living species are recognized in this genus, but new species
are still being discovered in both living and fossil coral
assemblages. The Latin name derives from the growth
mode, where branches are formed by a central or axial
polyp, which buds off numbers of a second kind, the
radial polyps, from around its tip as it extends. New
branches are formed by the development of new axial
polyps along the branch. This mode of growth, which
is similar to the axial mode in flowing plants, allows
many variations on a branching theme (Figure 1). It is
thought to have been a key character in the evolution
of a diverse array of species in Acropora, although other
processes are also proposed, such as hybridization and
reticulate evolution facilitated by the mass spawning of
related species.
Introduction
Six coral families (Acroporidae, Faviidae, Mussidae,
Poritidae, Fungiidae, and Pocilloporidae) dominate modern world reef composition, in terms of diversity, abundance, geographic range, and contribution to accretion of
reef carbonates. Of these, Acroporidae is arguably the
most successful, as the two most species-rich genera,
Acropora and Montipora, allow it to dominate the species
diversity and coral cover of most Indo-Pacific reef locations. Acropora the “staghorn” corals have played a role
in the biodiversity, ecology, and structure of coral reefs
for almost 60 million years (Schuster, 2003; Wallace and
Rosen, 2006). Their mode of skeletal construction, where
polyps are supported within an open “synapticular” framework (Figure 2), allow for rapid growth with efficient use
of calcium carbonate (Gladfelter, 2008) and provide habitat complexity for other reef biota (Munday, 2002). Strong
representation in mass coral spawning and recruitment
events, and rapid recolonization after destructive natural
events are the characteristics of Acropora (e.g., Babcock
et al., 1986; Connell et al., 2004): however, this genus
may experience severe localized or widespread loss of
diversity from major perturbations such as coral bleaching
due to elevated seawater temperature, cold-water events,
tsunamis, cyclone damage, and predator population outbreaks, particularly of Acanthaster planci, the crown-ofthorns sea star (Wilkinson, 1998–2008; Berklemans
et al., 2004; Marshall and Baird, 2006). Chronic anthropogenic impacts such as nutrient and sediment run-off,
Accommodation Space, Figure 1 Different models of fringing reef development show different modes of accommodation space
filling. (a): accommodation space is filled by corals showing catch-up or keep-up behavior. (b): reef accretion is lateral, having
established at a level with little or no vertical accommodation space. Isochrons are in thousands of radiocarbon years BP (From
Kennedy and Woodroffe, 2002).
ACROPORA
3
been argued that rates of sea level rise of $0.5 m by AD
2100 might create new accommodation space and switch
reef vertical accretion back on, with carbonate production
for the entire Great Barrier Reef rising from the current estimated 50 Mt a
À1 to 70 Mt a
À1 (Kinsey and Hopley, 1991).
Bibliography
Cowell, P. J., and Thom, B. G., 1994. Morphodynamics of coastal
evolution. In Carter, R. W. G., and Woodroffe, C. D., (eds.),
Coastal Evolution: late Quaternary shoreline morphodynamics.
Cambridge: Cambridge University Press, pp. 33–86.
Cowell, P. J., and Kench, P. S., 2002. The morphological response
of atoll islands to sea-level rise. Part 1: modifications to the
shoreface translation model. Journal of Coastal Research, ICS
2000, 633–644.
Gray, S. C., Hein, J. R., Hausmann, R., and Radtke, U., 1992. Geochronology and subsurface stratigraphy of Pukapuka and
Rakahanga atolls, Cook Islands: Late Quaternary reef growth
and sea level history. Palaeogeography, Palaeoclimatology,
Palaeoecology, 91, 377–394.
Grigg, R. W., 1998. Holocene coral reef accretion in Hawaii: a function
of wave exposure and sea level history. Coral Reefs, 17, 263–272.
Kennedy, D. M., and Woodroffe, C. D., 2002. Fringing reef growth
and morphology: a review. Earth Science Reviews, 57, 255–277.
Kinsey, D. W., and Hopley, D., 1991. The significance of coral reefs as
global carbon sinks – response to greenhouse. Palaeogeography,
Palaeoclimatology, Palaeoecology, 89, 363–377.
Quinn, T. M., and Matthews, R. K., 1990. Post-Miocene diagenetic
and eustatic history of Enewetak Atoll: Model and data comparison. Geology, 18, 942–945.
Smithers, S. G., Hopley, D., and Parnell, K. E., 2006. Fringing and
nearshore coral reefs of the Great Barrier Reef: episodic Holocene development and future prospects. Journal of Coastal
Research, 22, 175–187.
ACROPORA
Carden C. Wallace
Museum of Tropical Queensland, Townsville, QLD,
Australia
Synonyms
Arborescent corals; Axial branching corals; Midori ishi
(Japan); Staghorn corals; Table corals
Definition
Acropora (Oken, 1815) is the type genus of the hard coral
family Acroporidae (class Anthozoa, order Scleractinia
of the phylum Cnidaria). Currently, around 120–140 living species are recognized in this genus, but new species
are still being discovered in both living and fossil coral
assemblages. The Latin name derives from the growth
mode, where branches are formed by a central or axial
polyp, which buds off numbers of a second kind, the
radial polyps, from around its tip as it extends. New
branches are formed by the development of new axial
polyps along the branch. This mode of growth, which
is similar to the axial mode in flowing plants, allows
many variations on a branching theme (Figure 1). It is
thought to have been a key character in the evolution
of a diverse array of species in Acropora, although other
processes are also proposed, such as hybridization and
reticulate evolution facilitated by the mass spawning of
related species.
Introduction
Six coral families (Acroporidae, Faviidae, Mussidae,
Poritidae, Fungiidae, and Pocilloporidae) dominate modern world reef composition, in terms of diversity, abundance, geographic range, and contribution to accretion of
reef carbonates. Of these, Acroporidae is arguably the
most successful, as the two most species-rich genera,
Acropora and Montipora, allow it to dominate the species
diversity and coral cover of most Indo-Pacific reef locations. Acropora the “staghorn” corals have played a role
in the biodiversity, ecology, and structure of coral reefs
for almost 60 million years (Schuster, 2003; Wallace and
Rosen, 2006). Their mode of skeletal construction, where
polyps are supported within an open “synapticular” framework (Figure 2), allow for rapid growth with efficient use
of calcium carbonate (Gladfelter, 2008) and provide habitat complexity for other reef biota (Munday, 2002). Strong
representation in mass coral spawning and recruitment
events, and rapid recolonization after destructive natural
events are the characteristics of Acropora (e.g., Babcock
et al., 1986; Connell et al., 2004): however, this genus
may experience severe localized or widespread loss of
diversity from major perturbations such as coral bleaching
due to elevated seawater temperature, cold-water events,
tsunamis, cyclone damage, and predator population outbreaks, particularly of Acanthaster planci, the crown-ofthorns sea star (Wilkinson, 1998–2008; Berklemans
et al., 2004; Marshall and Baird, 2006). Chronic anthropogenic impacts such as nutrient and sediment run-off,
Accommodation Space, Figure 1 Different models of fringing reef development show different modes of accommodation space
filling. (a): accommodation space is filled by corals showing catch-up or keep-up behavior. (b): reef accretion is lateral, having
established at a level with little or no vertical accommodation space. Isochrons are in thousands of radiocarbon years BP (From
Kennedy and Woodroffe, 2002).
ACROPORA
3