WHAT IS HAPPENING ?
Coral colonies are made of hundreds of polyps, an invertebrate animal, living in symbiosis with a microscopic algae living in its tissues.
The polyp is host to the algae, which in return photosynthesises the food for the polyp. The polyp grows a calcium carbonate skeleton in order to expand the colony and accommodate new polyps. Like this, they have been thriving under the sun in the warm waters all around earth relying solely on their understanding. Under heat stress, the algae dies inside the polyps’ tissues causing the polyps to expel the algae, depriving themselves of their food source. The polyp is in fact transparent, and the algae gives it colouration. After the algae has left, the immaculate whiteness of the skeleton is left as if bleached. The polyps are thereafter getting weaker and may not survive if the water temperature stays high.
In 1998 we witnessed the devastating effect of an usual sea surface temperature increase, with 90% of coral mortality down to 15m, and similar events more recently in 2010. However well we control the carbon emissions, the warming forecast due to the inertia of the system alone is alarming. Scientists predict the demise of coral reefs by 2050, which leaves us very little time.
WHAT ARE THE IMPLICATIONS ?
In a country which owes its very existence to reef building corals, their death will directly affect the livelihood of the population. The whole setting in which the Maldivians evolve will be changed. The most dramatic consequence of them all would be the disappearance of the island themselves. Dead corals will indeed not grow upwards and keep up with rising sea levels.
Of course, there will be technical solutions to this problem, and some of them are already being implemented at large scale. Humans may finally be safe, constrained to a number of heavily fortified islands, but this has a cost far greater than that of the infrastructure!
Even though some local impacts are affecting the reef and could be better managed, the forecast temperature rise is equivalent to an ecological tsunami for the Maldivian coral reef ecosystem. The required rate of evolution for certain species may be faster than what is possible. As proof, the off springs of the 1998 survivors died in 2010. A demise of the corals will cause the disappearance of the many species depend on corals for their very existence.
WHAT CAN WE DO ?
Development is a fatality we have to face. Humans have heavily modified the surface of the earth to sustain an ever growing population. We engineer our terrestrial environment, but often pay a lot less attention to the marine aspect, especially in terms of ecology.
Mitigation or compensation can be achieved if only we could reprioritise the investments. In areas, Reefscapers installed thriving reefs in areas excavated for beach replenishment. In what was left as a grave yard we have created a thriving reef in a few years, with lots of fishes, a lot of them juveniles. Better still, these reefs are not fished at all and act as small scale marine protected areas. Through a greater mastery of the transplantation and increased understanding of the ecological processes, we will learn ways to engineer the marine environment in order to make it more diverse, more productive, help with aesthetics, recreational aspects and even coastal protection.
Corals are the major building blocks of this ecosystem, yet we know very little about how to manipulate them. Only a few years back, coral propagation was criticized as ineffective, causing more death than growth, but the success of the Reefscapers, among others, is turning the tables. On the land, we have very much learnt to manipulate trees, select them in order to get them adapted to different environments. It is time we take a similar direction for corals, learn more about their in situ characteristics, select them for their resistance and propagate them efficiently.