With the fragile ecology of coral reefs around the globe increasingly under pressure, scientists on Australia's Great Barrier Reef are establishing a network of sensors to better understand this beautiful part of the underwater world.
Coral reefs in several parts of the world are showing tentative signs of recovery after years of damage, scientists say. But they report the pattern is patchy, with improvements in some areas balanced by continued degradation in others.
Market forces appear to be at work on coral reefs, where fish that perform a cleaning service risk losing customers if they get sloppy. Scientists studying these fish conclude that healthy competition is sometimes important in ecology, helping to stabilise co-operation between species.