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Self-generated morphology in lagoon reefs.

Blakeway D, Hamblin MG - PeerJ (2015)

Bottom Line: In these situations reef morphology can be considered a phenotype of the predominant reef building organism.The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images.More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Earth and Environment, University of Western Australia , Crawley , Western Australia, Australia.

ABSTRACT
The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia's Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves-specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef.

No MeSH data available.


Related in: MedlinePlus

Plan view of model (A) and real (B) branching Acropora reefs.Only the uppermost 10 m of the model reef is shown, simulating an aerial view with 10 m water visibility. This reef grew in 100 iterations (4,000 years) from 225 corals seeded at the default colonisation density (0.25%) in a 300 × 300 m array. The real reefs shown in B are those from Fig. 1, in the Pelsaert Group of the Abrolhos. The arrowed annotations indicate the locations of photographs shown in Figs. 5A and 5B. Figure 10B is reproduced by permission of the Western Australian Land Information Authority (Landgate) 2015.
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fig-10: Plan view of model (A) and real (B) branching Acropora reefs.Only the uppermost 10 m of the model reef is shown, simulating an aerial view with 10 m water visibility. This reef grew in 100 iterations (4,000 years) from 225 corals seeded at the default colonisation density (0.25%) in a 300 × 300 m array. The real reefs shown in B are those from Fig. 1, in the Pelsaert Group of the Abrolhos. The arrowed annotations indicate the locations of photographs shown in Figs. 5A and 5B. Figure 10B is reproduced by permission of the Western Australian Land Information Authority (Landgate) 2015.

Mentions: Reefs created with the branching Acropora model closely resemble the Abrolhos cellular reefs (Fig. 10). The model reproduces the characteristic egg box form of the real reefs and all its corollaries including haystack reefs, stellate reefs with radiating ridges, reef platforms enclosing bowl-shaped depressions, scalloped platform margins and the presence of multiple small depressions within larger multi-lobed depressions. The 45° slopes of the model reefs are steeper than the mean of the real Acropora slopes (37° ± SD 6°) but within their recorded range. Figure 11 shows sequential stages in the development of the branching Acropora reefs, demonstrating the emergence of their egg box morphology. The key process is the formation of ridges between adjacent patch reefs. This process begins when the patch reefs meet, whereupon the valleys between them grow rapidly upward to become saddle-shaped ridges (Figs. 11C and 11D). The depressions surrounded by the reefs and ridges are initially irregular in outline but are progressively smoothed to subcircular shapes as the surrounding reef grows. Eventually the depressions become completely enclosed within the reef platform and infilled by coral (Fig. 11E).


Self-generated morphology in lagoon reefs.

Blakeway D, Hamblin MG - PeerJ (2015)

Plan view of model (A) and real (B) branching Acropora reefs.Only the uppermost 10 m of the model reef is shown, simulating an aerial view with 10 m water visibility. This reef grew in 100 iterations (4,000 years) from 225 corals seeded at the default colonisation density (0.25%) in a 300 × 300 m array. The real reefs shown in B are those from Fig. 1, in the Pelsaert Group of the Abrolhos. The arrowed annotations indicate the locations of photographs shown in Figs. 5A and 5B. Figure 10B is reproduced by permission of the Western Australian Land Information Authority (Landgate) 2015.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499466&req=5

fig-10: Plan view of model (A) and real (B) branching Acropora reefs.Only the uppermost 10 m of the model reef is shown, simulating an aerial view with 10 m water visibility. This reef grew in 100 iterations (4,000 years) from 225 corals seeded at the default colonisation density (0.25%) in a 300 × 300 m array. The real reefs shown in B are those from Fig. 1, in the Pelsaert Group of the Abrolhos. The arrowed annotations indicate the locations of photographs shown in Figs. 5A and 5B. Figure 10B is reproduced by permission of the Western Australian Land Information Authority (Landgate) 2015.
Mentions: Reefs created with the branching Acropora model closely resemble the Abrolhos cellular reefs (Fig. 10). The model reproduces the characteristic egg box form of the real reefs and all its corollaries including haystack reefs, stellate reefs with radiating ridges, reef platforms enclosing bowl-shaped depressions, scalloped platform margins and the presence of multiple small depressions within larger multi-lobed depressions. The 45° slopes of the model reefs are steeper than the mean of the real Acropora slopes (37° ± SD 6°) but within their recorded range. Figure 11 shows sequential stages in the development of the branching Acropora reefs, demonstrating the emergence of their egg box morphology. The key process is the formation of ridges between adjacent patch reefs. This process begins when the patch reefs meet, whereupon the valleys between them grow rapidly upward to become saddle-shaped ridges (Figs. 11C and 11D). The depressions surrounded by the reefs and ridges are initially irregular in outline but are progressively smoothed to subcircular shapes as the surrounding reef grows. Eventually the depressions become completely enclosed within the reef platform and infilled by coral (Fig. 11E).

Bottom Line: In these situations reef morphology can be considered a phenotype of the predominant reef building organism.The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images.More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Earth and Environment, University of Western Australia , Crawley , Western Australia, Australia.

ABSTRACT
The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia's Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves-specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef.

No MeSH data available.


Related in: MedlinePlus