Project 1.1.4 - Dating and mapping historical changes in Great Barrier Reef coral communities
Project Leader: Dr Jian-Xin Zhao, The University of
Queensland
A large number of dead
branching corals and massive coral heads, representing individual
life spans up to hundreds of years, exist among the coral
communities of coastal reefs. Modern dating methods using the TIMS
Uranium-series allow us to know the age of dead coral colonies
in situ on the Great Barrier Reef at a resolution of one
to three years over several hundred years of history. This allows
temporal bracketing of significant mortality events back to the
time of early European settlement of Queensland and beyond.
Knowledge of the age structure of the death assemblages can be
related to major human developmental events and recent mass
bleaching events related to global warming, so that the sources of
the mortality can be identified; management can be directed toward
ameliorating those sources. If the coral mortality has resulted in
substantial changes in reef coral community structure, then
management is in a position to understand what the previous state
of the reef was, and can overcome the ‘shifting baseline
syndrome’ whereby each new generation of managers and
scientists has a different view of what constitutes
‘natural’. The Great Barrier Reef Marine Park Authority
has already invested in this historical perspective through its
‘Historical Photographs’ initiative, and Project 1.1.4
intends to expand this perspective to inform the Authority about
the natural state of the coral reef.
Project 1.1.4 has three objectives:
-
Determine the decadal death rate of massive corals over the last
two hundred years (since European settlement);
-
Determine the variation in coral community structure over the
past two hundred years; and
-
Correlate rates of coral mortality with major human development
and recent El Niño events.
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