NASA
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| The Gulfstream III carrying NASA's PRISM instrument being readied for
science flights from Cairns, Australia. Credit: NASA/JPL-Caltech/BIOS. |
A NASA airborne mission designed to transform our understanding of
Earth's valuable and ecologically sensitive coral reefs has set up shop
in Australia for a two-month investigation of the Great Barrier Reef,
the world's largest reef ecosystem.
At a media briefing today at Cairns Airport in North Queensland,
Australia, scientists from NASA's COral Reef Airborne Laboratory (CORAL)
mission and their Australian collaborators discussed the mission's
objectives and the new insights they expect to glean into the present
condition of the Great Barrier Reef and the function of reef systems
worldwide.
"CORAL offers the clearest, most extensive picture to date of the
condition of a large portion of the world's coral reefs," said CORAL
Principal Investigator Eric Hochberg of the Bermuda Institute of Ocean
Sciences (BIOS), Ferry Reach, St. George's, Bermuda, prior to the
briefing. "This new understanding of reef condition and function will
allow scientists to better predict the future of this global ecosystem
and provide policymakers with better information for decisions regarding
resource management."
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| Bleached and stressed coral on the Great Barrier Reef. Credit: NASA/JPL-Caltech/BIOS. |
CORAL's three-year mission combines aerial surveys using
state-of-the-art airborne imaging spectrometer technology developed by
NASA's Jet Propulsion Laboratory, Pasadena, California, with in-water
validation activities. The mission will provide critical data and new
models for analyzing reef ecosystems from a new perspective. CORAL will
generate a uniform data set for a large sample of reefs across the
Pacific Ocean. Scientists can use these data to search for trends
between coral reef condition and the natural and human-produced
biological and environmental factors that affect reefs.
Over the next year, CORAL will survey portions of the Great Barrier
Reef, along with reef systems in the main Hawaiian Islands, the Mariana
Islands and Palau.
In Australia, CORAL will survey six discrete sections across the
length of the Great Barrier Reef, from the Capricorn-Bunker Group in the
south to Torres Strait in the north. Two locations on the reef — one
north (Lizard Island Research Station) and one south (Heron Island
Research Station) — will serve as bases for in-water validation
activities. Scientists from Australia's Commonwealth Scientific and
Industrial Research Organisation (CSIRO) and the University of
Queensland in Brisbane are collaborating with NASA and BIOS to conduct
additional complementary in-water validation activities.
The Great Barrier Reef: Australia's national treasure
Located in the Coral Sea off Queensland, the Great Barrier Reef
encompasses more than 2,900 individual reefs and 900 islands. It is more
than 1,400 miles (2,300 kilometers) long and covers an area of about
133,000 square miles (344,400 square kilometers). The largest single
structure made by living organisms on Earth, the reef teems with
biodiversity, including about 400 species of coral. It attracts about 2
million visitors a year; in turn, tourism and fishing generate billions
annually and employ tens of thousands of people. However, the reef faces
environmental pressures from various human and climate change impacts.
"The Great Barrier Reef is Australia's national treasure, so having a
broader understanding of its condition and what's threatening it will
help us better understand how we can protect it," said Tim Malthus,
research leader of CSIRO's Coastal Monitoring, Modeling and Informatics
Group in Canberra, Australia. "Along with surveying several large
sections of the reef, CORAL will also survey the health of corals in the
Torres Strait, a complex high-tide area that has been historically less
studied. It is also opportunistic for us to see if the reef is
recovering after the recent bleaching event."
Stuart Phinn, professor of geography at the University of Queensland
(UQ), said CORAL will provide Australian coral reef science and
management with unique new maps and mapping approaches. These will
expand ongoing efforts to map and understand Great Barrier Reef
dynamics. "Being able to support and collaborate on NASA's CORAL project
will enable groups like ours to advance our capabilities and transfer
them to Australian science and management agencies," Phinn said. "Part
of this includes building a process for mapping the entire reef. UQ and
CORAL will exchange field data, knowledge and experience to
cross-validate mapping and monitoring approaches."
An urgent need for better data
Around the world, concerns among scientists, resource managers and
the public that coral reef ecosystems are degrading at alarming rates
due to human-induced factors and global change have motivated increased
assessment and monitoring efforts. The urgency of the problem has forced
estimates of global reef status to be synthesized from a variety of
local surveys with disparate aims, methods and quality.
The problem with current assessments of reef degradation, said
Hochberg, is that the data supporting these predictions are not uniform
and surprisingly sparse. "Virtually all reef assessments to date rely on
in-water survey techniques that are laborious, expensive and limited in
spatial scope," he said. "Very little of Earth's reef area has been
directly surveyed. More importantly, there are no existing models that
quantitatively relate reef conditions to the full range of biological
and environmental factors that affect them -- models that can help
scientists better understand how coral reefs will respond to expected
environmental changes. CORAL addresses an urgent need in the face of
ongoing worldwide reef degradation, and also serves as a pathfinder for a
future satellite mission to globally survey the world's reefs."
Natural, balanced coral reefs comprise mosaics of coral, algae and
sand on the seafloor that, together, drive the structure and function of
reef ecosystems. When corals die, algae rapidly take over their
skeletons. A non-stressed, healthy reef will usually increase coral
coverage as it recovers from disturbance. But when a stressed reef is
disturbed, the carbonate structure of its coral erodes, and the reef
ultimately becomes a flat-bottom community dominated by algae, shifting
rubble and sand, with little to no coral recovery. Such ecosystem phase
shifts, as they are called, represent a radical change in a reef's
character, marked by a decline in the diversity of reef flora and fauna.
CORAL will generate scientific data products describing coral reef
condition, measuring three key components of reef health for which we
currently have limited data: composition, primary productivity and
calcification. Primary productivity is a measure of how much energy is
available to drive biological activity in a reef system. Calcification
measures the net gain in carbonates, which determine a reef's long-term
growth.
PRISM: Shining new light on coral reef condition
To accomplish its science objectives, CORAL will use JPL's Portable
Remote Imaging Spectrometer (PRISM). PRISM will literally peer through
the ocean's surface to generate high-resolution images of reflected
light in the specific regions of the electromagnetic spectrum important
to coral reef scientists. Mounted in the belly of a modified Tempus
Solutions Gulfstream IV aircraft, PRISM will survey reefs from an
altitude of 28,000 feet (8,500 meters) to generate calibrated scientific
data products.
"PRISM builds on an extensive legacy of JPL spectrometers that have
successfully operated for NASA and non-NASA missions," said Michelle
Gierach, NASA CORAL project scientist at JPL. "It provides the coral
reef science community with high-quality oceanographic imagery at the
accuracy, range, resolution, signal-to-noise ratio, sensitivity and
uniformity needed to answer key questions about coral reef condition.
PRISM data will be analyzed against data for 10 key biological and
environmental factors affecting coral reef ecosystems, acquired from
pre-existing data sources."
NASA collects data from space, air, land and sea to increase our
understanding of our home planet, improve lives and safeguard our
future. NASA develops new ways to observe and study Earth's
interconnected natural systems with long-term data records. The agency
freely shares this unique knowledge and works with institutions around
the world to gain new insights into how our planet is changing.
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