17
3. The Great Barrier Reef in
Time and Space: Geology
and Palaeobiology
J. M. Pandolfi & R. Kelley
N INTRODUCTION
Reefs in their many forms are found throughout the
fossil record and represent some of the earliest
structure-forming ecosystems on Earth. Since the
explosion of metazoans in the Cambrian around
540 My (million years ago) many groups of organisms
have formed ‘reef like’ features on the sea floor, making reef communities difficult to singularly characterise. Following the greatest extinction of all time, the
Permo-Triassic event (251 My), scleractinian corals,
bivalve molluscs, and crustose coralline algae have
dominated the construction of wave resistant organic
carbonate structures on the planet—commonly called
reefs.
While the definition of just what is a ‘reef’ has a
long and tortuous history of debate in the scientific
literature, there is no dispute about the importance of
the reef ecosystems of the coastlines, continental
shelves and ocean provinces of the tropical realm. In
this chapter we take a broad spatial and temporal
view of the largest of the world’s platform reef
provinces—the Great Barrier Reef (GBR). In particular
we look at the boundary conditions and mechanisms
that underpin the perpetuation of the GBR province
in space and time and how environmental change has
influenced the reef biota.
The last decade has seen an increasing appreciation of the importance of understanding the GBR from
a total system perspective. It has also seen the recognition of the need for a temporal perspective in every
aspect of ecology, especially where it seeks to relate to
natural resource management. Understanding the
ecosystems we live in and exploit over medium term
time scales allows natural resource managers to plan
for ecological resilience that is key to sustainability.
But what about the long term view? Geological
evidence accumulated over the last 30 years shows
that the ‘reef’ part of the GBR is a relatively young
feature—less than 1 million years old. Because reefs
are built mainly during rising sea levels, and the highest sea levels are associated with interglacial periods,
much of our attention is attracted towards GBR reef
growth during the interglacial high sea level episodes
of the last 500 000 years. But the GBR, like reefs elsewhere in the tropics, survived during lower sea level
stands as well. In this chapter we explore the life and
times of the GBR and the dynamic ecological response
of coral reefs to constant environmental change.
3. The Great Barrier Reef in
Time and Space: Geology
and Palaeobiology
J. M. Pandolfi & R. Kelley
N INTRODUCTION
Reefs in their many forms are found throughout the
fossil record and represent some of the earliest
structure-forming ecosystems on Earth. Since the
explosion of metazoans in the Cambrian around
540 My (million years ago) many groups of organisms
have formed ‘reef like’ features on the sea floor, making reef communities difficult to singularly characterise. Following the greatest extinction of all time, the
Permo-Triassic event (251 My), scleractinian corals,
bivalve molluscs, and crustose coralline algae have
dominated the construction of wave resistant organic
carbonate structures on the planet—commonly called
reefs.
While the definition of just what is a ‘reef’ has a
long and tortuous history of debate in the scientific
literature, there is no dispute about the importance of
the reef ecosystems of the coastlines, continental
shelves and ocean provinces of the tropical realm. In
this chapter we take a broad spatial and temporal
view of the largest of the world’s platform reef
provinces—the Great Barrier Reef (GBR). In particular
we look at the boundary conditions and mechanisms
that underpin the perpetuation of the GBR province
in space and time and how environmental change has
influenced the reef biota.
The last decade has seen an increasing appreciation of the importance of understanding the GBR from
a total system perspective. It has also seen the recognition of the need for a temporal perspective in every
aspect of ecology, especially where it seeks to relate to
natural resource management. Understanding the
ecosystems we live in and exploit over medium term
time scales allows natural resource managers to plan
for ecological resilience that is key to sustainability.
But what about the long term view? Geological
evidence accumulated over the last 30 years shows
that the ‘reef’ part of the GBR is a relatively young
feature—less than 1 million years old. Because reefs
are built mainly during rising sea levels, and the highest sea levels are associated with interglacial periods,
much of our attention is attracted towards GBR reef
growth during the interglacial high sea level episodes
of the last 500 000 years. But the GBR, like reefs elsewhere in the tropics, survived during lower sea level
stands as well. In this chapter we explore the life and
times of the GBR and the dynamic ecological response
of coral reefs to constant environmental change.