Encyclopedia of Modern Coral Reefs Structure Form and Process, Poradniki, ! Akwarystyka, akwarystyka morska, ...
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A
Outbreaks were first observed in the 1960s. The
geographical extent (two oceans) and impact (an ecosys-
tem changed from one dominated by hard corals to one
dominated by algae), shocked scientists. A key manage-
ment issue was whether human activity had somehow
precipitated the population outbreaks. Two main hypoth-
eses have been developed that implicate anthropogenic
factors. The first is
ACANTHASTER PLANCI
Ian Miller
Australian Institute of Marine Science, Townsville,
QLD, Australia
Acanthaster planci (Class Asteroidea; Order Spinulosida;
“
crown-of-thorns sea star or starfish
”
) is a large (up to
70 cm), mobile, multi-armed (7
–
23) sea star covered in
sharp, toxic spines. It feeds almost exclusively on hard
corals and is found on coral reefs throughout the Indo-
Pacific. No other reef sea stars remotely resemble its
appearance, nor possess comparable life-history traits as
a predator on corals.
Crown-of-thorns are prone to population outbreaks,
with aggregations of thousands or more adults per hectare
not uncommon (
Figure 1
). Such populations often
advance in fronts through coral habitat, leaving formerly
luxuriant coral areas dead in their wake. The sea star
has a number of life history traits that predisposes
these destructive population outbreaks: absence of any
equivalent coral predator (little competition for food);
a large stomach (that is pushed out through the mouth
to digest coral tissue externally); a high fecundity
(a mature female can produce some 50 million eggs);
planktonic larvae (that can feed in the water column and
disperse over long distances); rapid growth (
”
(Endean,
1969
), which holds that overfishing (in partic-
ular sweetlips (Family Lethrinidae), some wrasses (Fam-
ily Labridae) and some triggerfish (Family Balistidae))
and collecting of predators of the sea star (notably
a large Gastropod mollusc the giant triton Charonia
tritonis), allow crown-of-thorns to build up in numbers
on a reef. On reaching a critical abundance, their repro-
duction and larval dispersal leads to successful recruit-
ment of larvae on reefs downstream in prevailing
currents. A cascade of outbreaks across tracts of neigh-
boring reefs ensues. The second hypothesis (possibly
synergistic with the first) is
“
the nutrient enrichment
hypothesis
”
(Birkeland,
1982
, Lucas,
1982
). In this sce-
nario, river runoff from human-modified catchments
enhances nutrients in coastal waters, resulting in an
increase in phytoplankton upon which the sea star larvae
feed. Because crown-of-thorns produce such a vast
quantity of eggs even a small increase in survivorship
leads to larger settlement of larvae onto a reef, which
in turn leads to a primary outbreak.
Today, despite repeated outbreaks and years of
research the exact events leading to the initiation of an
outbreak remain enigmatic. This is because the life-
history of crown-of-thorns makes it difficult to disentan-
gle the natural processes leading to an outbreak from
those forced by human activities. As a result crown-of-
thorns remains a major management problem for coral
“
the predator removal hypothesis
10 cm.y
1
,
that is faster than any other coral reef sea star); large
size and toxic spiny armature (that provide protection
from potential predators); multi-armed morphology and
tube feet (allowing them to climb and feed in nearly any
position). Repeated population outbreaks have decimated
hard corals throughout
the Indo-Pacific over the last
50 years.
David Hopley (ed.), Encyclopedia of Modern Coral Reefs, DOI 10.1007/978-90-481-2639-2,
#
Springer Science+Business Media B.V. 2011
2
ACCOMMODATION SPACE
ACCOMMODATION SPACE
Tom Spencer
University of Cambridge, Cambridge, UK
Definition
The space available, in both a vertical and a lateral sense,
within which corals can grow, increase framework and
sediments accumulate.
Accommodation space
For corals, accommodation space is constrained vertically
by the water-air interface and its volume broadly deter-
mined by reef widths and slope angles. For sedimentary
accumulations on reef platforms, the lower boundary is
governed by reef margin position, reef flat elevation and
lagoon depth and the upper boundary set by the height
of wave run-up during storm events. The rate at which
accommodation space can be filled depends upon rates
of vertical coral growth, vertical framework accretion
and sediment supply, transport and accumulation; these
are all controlled by reef productivity and sediment gener-
ation processes which may themselves be constrained by
the environment processes (e.g., wave exposure locally
prevents coral growth from filling accommodation spaces
on Hawaii; Grigg,
1998
), be periodically interrupted by
storms (see
Tropical Cyclone/Hurricane
) and modulated
by sea level change, which ultimately determines the
upper margin of the accommodation space (
Figure 1
).
Over the long-term, a subsiding reef basement results in
an increase in accommodation space. During glacial
periods, emergent reefs were subject to subaerial solution,
thus increasing the vertical accommodation space available
for reef re-growth on renewed inundation during intergla-
cial periods. There has been debate over the subaerial
erosion rates involved, and thus the additional accommoda-
tion space generated, ranging from minimal downwearing
(e.g., Quinn and Matthews,
1990
)to6
–
63 cm of surface
lowering per 1,000 years (e.g., Gray et al.,
1992
). During
the stable sea-level of the late Holocene, there has been
“
turn-off
”
of both vertical and horizontal growth of some
reefs due to the progressive thinning of accommodation
space as reefs approached present sea level (which itself
may have fallen slightly in some Indo-Pacific locations,
thus further reducing accommodation space) and the diffi-
culty of lateral expansion, and maintenance of reef front
volume and integrity, over relatively unstable reef front
talus deposits in increasing water depths. For example,
Smithers et al. (
2006
) attributed the shut-down of fringing
and nearshore reef progradation on the Great Barrier Reef
between 5.5
Acanthaster Planci, Figure 1 A crown-of-thorns feeding
aggregation. Such outbreaks of the sea star are a major recurrent
cause of coral mortality on coral reefs throughout the
Indo-Pacific (photo: AIMS LTMP).
reefs. Where adults have been collected as a control
measure, coral has been saved from predation only over
relatively small areas (hectares). In the past, coral cover
has generally recovered within 10
–
15 years of an out-
break. However coral resilience in the face of future out-
breaks is uncertain (Done,
1987
). This is because the
size and frequency of other impacts that can effect coral
reefs (such as cyclones, coral bleaching, and ocean acid-
ification) are predicted to increase in coming years due
to greenhouse gas emissions. Without full recovery,
repeated outbreaks will eventually lead to the degrada-
tion of the coral reef community.
Bibliography
Birkeland, C., 1982. Terrestrial runoff as a cause of outbreaks of
Acanthaster planci (Echinodermata: Asteroidea). Marine Biology,
69
185.
Birkeland, C., and Lucas, S. L., 1990. Acanthaster planci: major
management problem of coral reefs. Boca Raton, Florida: CRC
Press.
Done, T. J., 1987. Simulation of the effects of Acanthaster planci on
the population structure of massive corals in the genus Porites:
evidence of population resilience? Coral Reefs,
6
,75
–
90.
Endean, R., 1969. Report on Investigations Made into Aspects
of the Current Acanthaster planci (Crown-of-thorns) Infesta-
tions of Certain Reefs of the Great Barrier Reef. Fisheries
Branch, Queensland Dept. of Primary Industries, Brisbane.
p. 35.
Lucas, J. S., 1982. Quantitative studies of feeding and nutrition dur-
ing larval development of the coral reef asteroid Acanthaster
planci (L.). Journal of Experimental Marine Biology and Ecol-
ogy,
,175
–
2.5 ka BP to the contrac-
tion of accommodation space caused by the reefs
–
4.8 ka BP and 3.0
–
65
, 173
–
194.
own
growth and the complete occupation of favorable reef foun-
dations. In the short term, local accommodation space is an
outcome of local reef erosion and the re-configuration of
sedimentary accumulations resulting from hurricane and
’
Cross-references
Coral Reef, Definition
Corals: Environmental Controls on Growth
ACROPORA
3
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
).
cyclone impacts (see Tropical Cyclone/Hurricane). It has
been argued that rates of sea level rise of
of the phylum Cnidaria). Currently, around 120
140 liv-
ing 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.
–
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 esti-
mated 50 Mt a
1
to 70 Mt a
1
(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. Geo-
chronology 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,
–
Introduction
Six coral families (Acroporidae, Faviidae, Mussidae,
Poritidae, Fungiidae, and Pocilloporidae) dominate mod-
ern world reef composition, in terms of diversity, abun-
dance, 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 loca-
tions. Acropora the
272.
Kennedy, D. M., and Woodroffe, C. D., 2002. Fringing reef growth
and morphology: a review. Earth Science Reviews,
17
, 263
–
277.
Kinsey, D. W., andHopley, 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 compar-
ison. 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 Holo-
cene development and future prospects. Journal of Coastal
Research,
22
, 175
–
187.
57
, 255
–
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
”
frame-
work (
Figure 2
), allow for rapid growth with efficient use
of calcium carbonate (Gladfelter, 2008) and provide habi-
tat 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 frommajor perturbations such as coral bleaching
due to elevated seawater temperature, cold-water events,
tsunamis, cyclone damage, and predator population out-
breaks, particularly of Acanthaster planci, the crown-of-
thorns sea star
“
staghorn
”
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
2008; Berklemans
et al., 2004; Marshall and Baird,
2006
). Chronic anthropo-
genic impacts such as nutrient and sediment run-off,
(Wilkinson, 1998
–
4
ACROPORA
Acropora, Figure 1 Examples of colony shapes in Acropora:(a) Arborescent (A. grandis), (b) Arborescent table (A. valenciennesi),
(c) Corymbose (A. anthocercis), (d) Digitate (A. gemmifera), (e) Hispidose (A. echinata), and (f) Table (A. clathrata). (Photos: P. Muir.)
overfishing, and coral mining for limestone also have an
impact on Acropora (Fabricius,
2005
; Fabricius and
Wolanski,
2000
; Brown,
1997
).
now restricted to a genus of non-zooxanthellate deepwater
corals. The name Acropora was stabilized by a decision of
the International Code of Nomenclature in the mid-
twentieth century (Boschma,
1961
; China, 1983), which
also ruled on a type species, A. muricata (Linneaus,
1758
). A dilemma concerning the nature and provenance
of this species, described by Linnaeus as being from the
Nomenclatural issues
Until the late nineteenth century Acropora was known
mostly as Madrepora, a broadly applied name, which is
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zanotowane.pl doc.pisz.pl pdf.pisz.pl upanicza.keep.pl
A
Outbreaks were first observed in the 1960s. The
geographical extent (two oceans) and impact (an ecosys-
tem changed from one dominated by hard corals to one
dominated by algae), shocked scientists. A key manage-
ment issue was whether human activity had somehow
precipitated the population outbreaks. Two main hypoth-
eses have been developed that implicate anthropogenic
factors. The first is
ACANTHASTER PLANCI
Ian Miller
Australian Institute of Marine Science, Townsville,
QLD, Australia
Acanthaster planci (Class Asteroidea; Order Spinulosida;
“
crown-of-thorns sea star or starfish
”
) is a large (up to
70 cm), mobile, multi-armed (7
–
23) sea star covered in
sharp, toxic spines. It feeds almost exclusively on hard
corals and is found on coral reefs throughout the Indo-
Pacific. No other reef sea stars remotely resemble its
appearance, nor possess comparable life-history traits as
a predator on corals.
Crown-of-thorns are prone to population outbreaks,
with aggregations of thousands or more adults per hectare
not uncommon (
Figure 1
). Such populations often
advance in fronts through coral habitat, leaving formerly
luxuriant coral areas dead in their wake. The sea star
has a number of life history traits that predisposes
these destructive population outbreaks: absence of any
equivalent coral predator (little competition for food);
a large stomach (that is pushed out through the mouth
to digest coral tissue externally); a high fecundity
(a mature female can produce some 50 million eggs);
planktonic larvae (that can feed in the water column and
disperse over long distances); rapid growth (
”
(Endean,
1969
), which holds that overfishing (in partic-
ular sweetlips (Family Lethrinidae), some wrasses (Fam-
ily Labridae) and some triggerfish (Family Balistidae))
and collecting of predators of the sea star (notably
a large Gastropod mollusc the giant triton Charonia
tritonis), allow crown-of-thorns to build up in numbers
on a reef. On reaching a critical abundance, their repro-
duction and larval dispersal leads to successful recruit-
ment of larvae on reefs downstream in prevailing
currents. A cascade of outbreaks across tracts of neigh-
boring reefs ensues. The second hypothesis (possibly
synergistic with the first) is
“
the nutrient enrichment
hypothesis
”
(Birkeland,
1982
, Lucas,
1982
). In this sce-
nario, river runoff from human-modified catchments
enhances nutrients in coastal waters, resulting in an
increase in phytoplankton upon which the sea star larvae
feed. Because crown-of-thorns produce such a vast
quantity of eggs even a small increase in survivorship
leads to larger settlement of larvae onto a reef, which
in turn leads to a primary outbreak.
Today, despite repeated outbreaks and years of
research the exact events leading to the initiation of an
outbreak remain enigmatic. This is because the life-
history of crown-of-thorns makes it difficult to disentan-
gle the natural processes leading to an outbreak from
those forced by human activities. As a result crown-of-
thorns remains a major management problem for coral
“
the predator removal hypothesis
10 cm.y
1
,
that is faster than any other coral reef sea star); large
size and toxic spiny armature (that provide protection
from potential predators); multi-armed morphology and
tube feet (allowing them to climb and feed in nearly any
position). Repeated population outbreaks have decimated
hard corals throughout
the Indo-Pacific over the last
50 years.
David Hopley (ed.), Encyclopedia of Modern Coral Reefs, DOI 10.1007/978-90-481-2639-2,
#
Springer Science+Business Media B.V. 2011
2
ACCOMMODATION SPACE
ACCOMMODATION SPACE
Tom Spencer
University of Cambridge, Cambridge, UK
Definition
The space available, in both a vertical and a lateral sense,
within which corals can grow, increase framework and
sediments accumulate.
Accommodation space
For corals, accommodation space is constrained vertically
by the water-air interface and its volume broadly deter-
mined by reef widths and slope angles. For sedimentary
accumulations on reef platforms, the lower boundary is
governed by reef margin position, reef flat elevation and
lagoon depth and the upper boundary set by the height
of wave run-up during storm events. The rate at which
accommodation space can be filled depends upon rates
of vertical coral growth, vertical framework accretion
and sediment supply, transport and accumulation; these
are all controlled by reef productivity and sediment gener-
ation processes which may themselves be constrained by
the environment processes (e.g., wave exposure locally
prevents coral growth from filling accommodation spaces
on Hawaii; Grigg,
1998
), be periodically interrupted by
storms (see
Tropical Cyclone/Hurricane
) and modulated
by sea level change, which ultimately determines the
upper margin of the accommodation space (
Figure 1
).
Over the long-term, a subsiding reef basement results in
an increase in accommodation space. During glacial
periods, emergent reefs were subject to subaerial solution,
thus increasing the vertical accommodation space available
for reef re-growth on renewed inundation during intergla-
cial periods. There has been debate over the subaerial
erosion rates involved, and thus the additional accommoda-
tion space generated, ranging from minimal downwearing
(e.g., Quinn and Matthews,
1990
)to6
–
63 cm of surface
lowering per 1,000 years (e.g., Gray et al.,
1992
). During
the stable sea-level of the late Holocene, there has been
“
turn-off
”
of both vertical and horizontal growth of some
reefs due to the progressive thinning of accommodation
space as reefs approached present sea level (which itself
may have fallen slightly in some Indo-Pacific locations,
thus further reducing accommodation space) and the diffi-
culty of lateral expansion, and maintenance of reef front
volume and integrity, over relatively unstable reef front
talus deposits in increasing water depths. For example,
Smithers et al. (
2006
) attributed the shut-down of fringing
and nearshore reef progradation on the Great Barrier Reef
between 5.5
Acanthaster Planci, Figure 1 A crown-of-thorns feeding
aggregation. Such outbreaks of the sea star are a major recurrent
cause of coral mortality on coral reefs throughout the
Indo-Pacific (photo: AIMS LTMP).
reefs. Where adults have been collected as a control
measure, coral has been saved from predation only over
relatively small areas (hectares). In the past, coral cover
has generally recovered within 10
–
15 years of an out-
break. However coral resilience in the face of future out-
breaks is uncertain (Done,
1987
). This is because the
size and frequency of other impacts that can effect coral
reefs (such as cyclones, coral bleaching, and ocean acid-
ification) are predicted to increase in coming years due
to greenhouse gas emissions. Without full recovery,
repeated outbreaks will eventually lead to the degrada-
tion of the coral reef community.
Bibliography
Birkeland, C., 1982. Terrestrial runoff as a cause of outbreaks of
Acanthaster planci (Echinodermata: Asteroidea). Marine Biology,
69
185.
Birkeland, C., and Lucas, S. L., 1990. Acanthaster planci: major
management problem of coral reefs. Boca Raton, Florida: CRC
Press.
Done, T. J., 1987. Simulation of the effects of Acanthaster planci on
the population structure of massive corals in the genus Porites:
evidence of population resilience? Coral Reefs,
6
,75
–
90.
Endean, R., 1969. Report on Investigations Made into Aspects
of the Current Acanthaster planci (Crown-of-thorns) Infesta-
tions of Certain Reefs of the Great Barrier Reef. Fisheries
Branch, Queensland Dept. of Primary Industries, Brisbane.
p. 35.
Lucas, J. S., 1982. Quantitative studies of feeding and nutrition dur-
ing larval development of the coral reef asteroid Acanthaster
planci (L.). Journal of Experimental Marine Biology and Ecol-
ogy,
,175
–
2.5 ka BP to the contrac-
tion of accommodation space caused by the reefs
–
4.8 ka BP and 3.0
–
65
, 173
–
194.
own
growth and the complete occupation of favorable reef foun-
dations. In the short term, local accommodation space is an
outcome of local reef erosion and the re-configuration of
sedimentary accumulations resulting from hurricane and
’
Cross-references
Coral Reef, Definition
Corals: Environmental Controls on Growth
ACROPORA
3
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
).
cyclone impacts (see Tropical Cyclone/Hurricane). It has
been argued that rates of sea level rise of
of the phylum Cnidaria). Currently, around 120
140 liv-
ing 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.
–
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 esti-
mated 50 Mt a
1
to 70 Mt a
1
(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. Geo-
chronology 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,
–
Introduction
Six coral families (Acroporidae, Faviidae, Mussidae,
Poritidae, Fungiidae, and Pocilloporidae) dominate mod-
ern world reef composition, in terms of diversity, abun-
dance, 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 loca-
tions. Acropora the
272.
Kennedy, D. M., and Woodroffe, C. D., 2002. Fringing reef growth
and morphology: a review. Earth Science Reviews,
17
, 263
–
277.
Kinsey, D. W., andHopley, 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 compar-
ison. 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 Holo-
cene development and future prospects. Journal of Coastal
Research,
22
, 175
–
187.
57
, 255
–
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
”
frame-
work (
Figure 2
), allow for rapid growth with efficient use
of calcium carbonate (Gladfelter, 2008) and provide habi-
tat 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 frommajor perturbations such as coral bleaching
due to elevated seawater temperature, cold-water events,
tsunamis, cyclone damage, and predator population out-
breaks, particularly of Acanthaster planci, the crown-of-
thorns sea star
“
staghorn
”
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
2008; Berklemans
et al., 2004; Marshall and Baird,
2006
). Chronic anthropo-
genic impacts such as nutrient and sediment run-off,
(Wilkinson, 1998
–
4
ACROPORA
Acropora, Figure 1 Examples of colony shapes in Acropora:(a) Arborescent (A. grandis), (b) Arborescent table (A. valenciennesi),
(c) Corymbose (A. anthocercis), (d) Digitate (A. gemmifera), (e) Hispidose (A. echinata), and (f) Table (A. clathrata). (Photos: P. Muir.)
overfishing, and coral mining for limestone also have an
impact on Acropora (Fabricius,
2005
; Fabricius and
Wolanski,
2000
; Brown,
1997
).
now restricted to a genus of non-zooxanthellate deepwater
corals. The name Acropora was stabilized by a decision of
the International Code of Nomenclature in the mid-
twentieth century (Boschma,
1961
; China, 1983), which
also ruled on a type species, A. muricata (Linneaus,
1758
). A dilemma concerning the nature and provenance
of this species, described by Linnaeus as being from the
Nomenclatural issues
Until the late nineteenth century Acropora was known
mostly as Madrepora, a broadly applied name, which is
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