Coral reefs, soos tropiese reënwoude, het 'n spesiale plek in die natuurgeskiedenis. Dek net 0.2% van die seebodem, hulle is die tuiste van ongeveer 'n kwart van alle seespesies. As gevolg van hierdie vrugbaarheid, and their flamboyant array of colours, shapes and sizes, reefs are rightly understood as wonders of the world. Reports of their destruction carry a painful sting. Like images of the burning Amazon, pictures of bleached coral are disturbing – their whitened, empty forms a warning of nature’s wider decline.
There is now around half the amount of coral that there was in the 1950s, and the outlook is not good. Rising sea temperatures, coastal and marine developments, overfishing and pollution all expose these highly sensitive environments to acute stress.
While a bleached reef can seem permanently lost, if conditions are right it can recover naturally. If the cause of bleaching (usually unnaturally high sea temperatures) stops, the corals are able to recapture the symbiotic algae that are released during bleaching and can make a full recovery. If the stress lasts for longer and the coral dies, it is possible for reefs to be recolonised by the planktonic young of healthy corals nearby. Egter, the overgrowth of reef algae can prevent this from happening and this is exacerbated by overfishing. After the disastrous bleaching event of 1998, which destroyed 8% of all coral, there have been subsequent losses of 14% tussen 2009 en 2018.
Whether it is a better strategy to shock people, or to try to stimulate conservation efforts by encouraging them to value nature more, is among the vexed questions of environmental communication. Sometimes the problem of the enormous demands placed on the Earth by nearly 8 billion people can seem overwhelming. Images of devastated landscapes, and warnings of tipping points, can induce feelings of despair.
Coral’s uniqueness and fragility make it a case in point. It is no wonder that some scientists, fearful of the impact of reef loss on tourism and livelihoods as well as for its own sake, is recreating coral habitats in laboratories. One such project, the Bahamas-based Coral Vita, was among the winners of the inaugural Earthshot prizes launched by Prince William. It is far-fetched to imagine that whole reef systems could be rebuilt by humans. But marine biology has taught us that reef-building corals, of which there are an estimated 800 species (along with thousands of other types), are more resilient than we thought. The biodiversity of reefs is their strength, as multiple species have evolved together to occupy different niches. If global heating can be halted, there is reason to hope that some of the creatures that inhabit these ecosystems will adapt to survive.
We should also look beyond the brightly coloured, sunlit reefs of the tropics, to other marine landscapes. One of the reasons coral is studied and admired is that it is more accessible – to scientists as well as tourists and film-makers – than ecosystems such as offshore mud habitats, or the horse mussel reefs in deep water around the British Isles. Tropical coral reefs deserve their status as charismatic habitats. But as awareness grows of the role that oceans can play in sequestering carbon, and marine conservation efforts ramp up as part of global efforts to limit warming and biodiversity losses, we should cultivate our appreciation for other ecosystems too.