The decline of tropical reefs should alarm us. But there is reason to hope

The planet’s tropical reefs are in decline, and we should be alarmed. But, as recently reported by The Guardian, there is still hope that they will adapt and survive.

While coral reefs only cover around 0.2% of the sea’s floor, they house a quarter of all oceanic species. This impressive level of biodiversity, and their breathtaking appearance - with colourful undersea gardens and fascinating landscapes seen nowhere else on earth - have helped position coral reefs as natural wonders of the world. As a result, reports of their destruction feel like such a powerful blow against the planet. Like other disturbing images of our natural world in decline, including poaching and deforestation, the sight of a bleached coral reef feels like a warning of what is to come if fast action isn’t taken.

Today, the ocean has about half the amount of coral than it did in the 1950s, and that number is set to decrease. Pollution, overfishing, rising sea temperatures, acidification, and rampant development in coastal and marine areas all put stress on these already endangered underwater environments. A single disastrous bleaching event in 1998 destroyed 8% of the planet’s coral. And, an additional 14% was lost between 20019 and 2018.

While the ghostly appearance of bleached coral may seem beyond revival, fortunately, it can recover under the right conditions. For example, if the cause of bleaching – typically acidification or abnormally high ocean temperatures – stops for long enough, the coral still stands a fighting chance. It may be able to recapture its symbiotic algae coating previously lost to bleaching, making a slow but full recovery. Even if the stress lasts for long enough that the coral dies, all hope is not lost. Some reefs can be recolonised by the spawn of healthy corals living nearby. Unfortunately, the rapid overgrowth of algae can halt this reef recolonisation – an issue exacerbated by overfishing. 

In the world of environmental communications, there is a debate over whether it is better to shock the public with striking images and statistics, or try to promote the value of these at-risk ecosystems. No matter which tactic is used to convey the point, there’s no question that the Earth is in trouble. Startling images of devastated landscapes like bleached coral reefs and harsh warnings of environmental tipping points can certainly induce feelings of despair. But does that emotional impact add up to change?

Some scientists don’t think so, preferring to work toward coral reef restoration rather than mourn its loss. Fearful of the global impact of reef loss on tourism, the livelihoods of local people, and the planetary ecosystem, researchers are turning their attention to recreating coral habitats in laboratories. And, while it would be impossible for humans to entirely rebuild our oceans’ reefs, their work has shown us that reef-building corals are surprisingly resilient. 

With over 800 species in total, reef-building corals could be the key to restoring and rebuilding essential habitats–- if the heating of our world’s oceans can be halted for long enough to let them rebound. These artificially created reefs also allow the study of biodiversity when it comes to coral, teaching us how multiple species work together to occupy different niches, and hopefully shedding light on how ecosystems will adapt to survive warming seas.

The scientific community also reminds us that we should look beyond brightly coloured tropical reefs and charismatic wildlife, to other lesser-known marine landscapes. Coral is studied and admired, in part, because it is both beautiful and accessible - unlike deepwater habitats and less attractive aquatic environments. Of course, coral reefs deserve their status as poster habitats for conservation, but as we learn how essential oceans are to sequestering carbon and slowing climate change and minimising biodiversity loss, it will become vital to cultivate an appreciation for other ecosystems, as well.