1. Natural wonder
One of the world’s seven natural wonders, the Great Barrier Reef contains some 900 islands and 3,000 smaller reefs. It is larger than the UK, the Netherlands and Switzerland combined, home to around 10% of the world’s marine fish, over 200 bird species and countless other animals, including turtles and dolphins.
But this iconic reef system is facing unprecedented threats. Together with governments, scientists are playing a key role in the battle to preserve this vulnerable ecosystem before it’s too late.
2. A degenerating reef
These are just a few examples of the many habitats and species in decline in recent decades.
3. Prevailing threats
Scroll through the images to find out what's destroying the Great Barrier Reef. With growing populations, industry and climate change, these threats are set to get worse. Some scientists think the reef in its current diverse form could be largely gone by 2050 if nothing is done.
4. WATCH: Need for speed
Corals have evolved to adapt to major changes throughout time. But the changes caused by humans are so fast, corals seem unlikely to be able to keep up. Watch the video below to see the ways some scientists are giving nature a helping hand.
Audio of Prof Madeleine van Oppen from the Australian Institute of Marine Science (AIMS), courtesy of Science in Action (BBC World Service, 2015). First five images courtesy of AIMS; remaining images courtesy of Getty.
5. Urgent scientific solutions
As well as assisting natural adaptation, scientists are looking at a number of other ways to restore and protect the Great Barrier Reef.
Exploring the extreme
There are already some corals, like those living in mangrove forests or near undersea volcanic vents, that can survive in warm or acidic water.
Marine biologists are exploring these extreme environments to see how the corals manage to survive here, and whether these species could re-populate reefs that are decimated elsewhere.
Better pest control
Outbreaks of Crown of Thorns starfish are managed by culling them with a poison injection. Scientists have improved the chemicals and techniques used in this process, making it 10 times more efficient over a two-year period.
But injecting individual starfish is still impractical. In the 2015 outbreak, there were five million on a stretch of reef between Cooktown and Cairns, and they continue to multiply and spread southwards.
So research is focusing on preventing outbreaks with management across the whole area, from land to river and sea.
Scientists have set up monitoring systems to model reef conditions, to better understand how the ecosystem is changing.
For example, satellite images are collected every day and compared against records, which reveal small fluctuations in the health of the corals, as well as environmental conditions like temperature and pollution.