NEWS UPDATE VIA THE BBC
STATUS OF CORAL REEFS:
Great Barrier Reef suffered worst bleaching on record in 2016.
By Hywel GriffithBBC News,
Sydney 28 November 2016
Higher water temperatures in 2016 caused the worst destruction of corals ever recorded on Australia's Great Barrier Reef, a study has found.
Some 67% of corals died in the reef's worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.
The situation was better in the central section, where 6% perished, while the southern reef is in good health.
But scientists warn recovery could be difficult if climate change continues.
Coral bleaching happens when water temperatures rise for a sustained period of time.
In February, March and April, sea surface temperatures across the Great Barrier Reef were the hottest on record, at least 1C higher than the monthly average.
"Some of the initial mortality was down to heat stress," said study leader Professor Terry Hughes. "The coral was cooked."
How bleaching occurs: Far more has been lost through gradual starvation, after the coral expelled the colourful algae zooxanthella, which turns sunlight into food.
This is what leads to the white, skeletal appearance of the coral, which is left without its main source of energy.
The study also found that the coral which survived the bleaching have now come under greater threat from predators such as snails and crown of thorns starfish.
This year's mass bleaching was the worst-ever recorded on the Great Barrier Reef, following two previous events in 1998 and 2002.
Professor Hughes is certain that the increased water temperature is the result of carbon emissions, and warns that climate change could bring annual bleaching within 20 years. "Most of the losses in 2016 have occurred in the northern, most pristine part of the Great Barrier Reef," he said."This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected."
Where is the damage? One of the worst-hit areas is around Lizard Island in Far North Queensland, where around 90% of the coral has died.
Dr Andrew Hoey, whose team charted the
area, said the impact was far worse than feared after an initial survey in April.
"It's devastating to get in the water somewhere you've been coming for almost 20 years, and it's just knocked it on its head," he said.
Bleaching is caused when water temperatures rise for a sustained period
"There's very little coral cover left there. It was dominated by the acropora - the branching corals - but we lost most of them."
Lizard Island is home to a research station, where scientists from across the world have come for decades to study marine life
One of its directors, Dr Anne Hogget, said this was by far the worst event to hit the Great Barrier Reef since she started working there in 1990. "We had bleaching here in 2002," she said. "We thought this was bad at the time, but this has blown it completely out of the water."
She is hopeful that the reef is capable of recovery, but fears it may not be give an opportunity, as sea temperatures continue to rise.
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ARC CENTRE OF EXCELLENCE FOR CORAL REEF STUDIES
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THANK YOU NASA/JPL: THESE ARE YOUR SPACE AGENCIES
USING THE VANTAGE POINT OF SPACE TO INCREASE OUR UNDERSTANDING OF OUR HOME PLANET
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.
Five Things About Coral Reefs and CORAL
1. More than just a pretty face. Hard corals have outlived dinosaurs, existing on Earth since the mid-Triassic period, 200-250 million years ago. During this time, they've evolved and diversified to exist across the world's ocean. Reef building corals typically occupy shallow tropical and subtropical waters; however, deep-water corals can be found at depths up to 20,000 feet (6,000 meters), and coral reefs were recently discovered at the mouth of the Amazon River in turbid, muddy water.
2. Coral reef ecosystems play a vital role in maintaining Earth's marine biodiversity and are also valuable to humans as a source of food, medical advances and tourism revenue, with total global ecosystem goods and services estimated at $400 billion each year. This number is especially impressive if you consider that the U.N. Environment Programme estimates that all the world's reefs would fit into an area smaller than the state of Arizona.
3. Reefs are mostly unknown territory. Search online for "coral reef images" and you'll get a million spectacular photos, but they all show just the small fraction of the world's reef area that scuba divers have visited. The fraction that has been scientifically surveyed is even smaller. We simply don't have enough data to understand which impacts to reefs are the most damaging and how resilient reefs are likely to be.
4. Scuba diving for science. For decades, scuba diving has been the gold standard for conducting reef research, allowing scientists to study everything from coral reproduction to the complex relationships between coral and other organisms. However, scuba diving as a method of understanding entire ecosystems leaves a lot to be desired: it is time consuming, labor intensive and costly. CORAL's use of remote sensing technology to survey entire reef ecosystems represents a huge step forward in research capacity.
5. Coral or reef? A single coral polyp -- consisting of the coral animal, its symbiotic algae and calcium carbonate skeleton -- is usually less than half an inch (one centimeter) across. Unlike many animals, corals are colonial, which means that many polyps grow together and form a larger structure. Most corals that you see in aquaria are, in fact, colonies. A coral reef, on the other hand, is an entire ecosystem that includes the individual polyps and their colonies, plus other living (e.g., fish, worms, invertebrates, algae) and nonliving (e.g., sunlight, sand, water) components. Scientists have a pretty good understanding of how individual coral polyps and colonies function, but much less understanding of how the various parts of a reef act individually and collectively to form an ecosystem. CORAL is the first opportunity to study reefs at the ecosystem scale, rather than relying on patchy, inconsistent surveys.
NASA's new COral Reef Airborne Laboratory (CORAL) field campaign kicks off its data-gathering phase with an operational readiness test on Oahu, Hawaii, starting the week of June 6. Over the next year, CORAL will conduct airborne and in-water surveys of representative coral reefs from Hawaii to Australia. By focusing on entire reef ecosystems, CORAL scientists will get state-of-the-art insights into how biological, physical and chemical processes shape and affect the ecosystems. These data will help them answer fundamental questions about how reefs are changing globally due to the effects of climate change and human activities.
How does CORAL work? It uses a new NASA airborne instrument designed specifically to observe coastal environments. The Portable Remote Imaging SpectroMeter (PRISM) can see objects about five feet by five feet square (less than two meters by two meters square) from its airborne perch five miles (eight kilometers) overhead. PRISM will fly in a Gulfstream IV airplane, collecting large swaths of data that will allow scientists to distinguish among coral, algae and sand -- important information for assessing reef condition -- without having to go underwater in each location. This uniform dataset will be an advance over the current data, collected by multiple groups all using different techniques.
For more information about NASA's Earth science activities, visit:
http://www.nasa.gov/earth
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