Fading corals of Africa's coasts By LINLEY BIGNOUX in Port Luis and JANET OTIENO in Nairobi | Tuesday, August 7 2012 at 10:25
Though vulnerable to storms and other harsh climatic conditions, coral reefs are still the greatest storehouse of biodiversity.
They are now the most threatened marine systems such that environmentalists have raised a red flag, warning that we could lose up to 70 per cent of coral reefs by 2050 if we do not spring to action.
Corals are the foundation of the tropical aquatic ecosystem, which is one of the most opulent in the world alongside a biodiversity exceeding that found in the richest tropical forests on earth. Coral reefs are home to fish, turtles, sharks, eels, crabs, shrimps, urchins, sponges and algae among others.
With Africa withstanding the worst of rapid climate change, the beautiful corals on our coasts are now on the verge of extinction.
They play a critical role in the marine food chain. Coral reefs constitute the largest animal creation mechanism on earth and its “inherent” links with human induced climate change has led to part of the ecosystem's downfall.
They form part of coastal marine wealth and ecosystems crucial for livelihood of people and various countries’ economies.
Oceanographer and environmental engineer Vassen Kauppaymuthoo told Africa Review in Port Louis that the links between climate change and dying corals cannot be undervalued, citing its huge importance and some of its perils.
“Climate change issues such as the increase in atmospheric and sea water temperature, sea level rise, but equally the acidification of the oceans linked to the dissolution of carbon dioxide in ocean waters have all caused intensive damages to coral reefs.”
“This means that apart from the attractiveness of our lagoons for tourists and money, the collapse of coral ecosystems may have wider consequences on the whole life system of our oceans which is in danger of collapsing, and this may cause widespread global damage to food and oxygen supply and threaten humanity.”
“It is important to know that 80 per cent of the oxygen we breathe comes from the oceans. In the Blue Bay marine park in Mauritius, the damage is so widespread that corals are dead at the level of 80 per cent in certain areas, a rate that is not recoverable but could in fact worsen if the current trend is maintained.
“There are equally direct human causes linked to mechanical removal and lack of application of international conventions protecting coral reefs.”
He added that Mauritius is currently facing lagoon backfilling by hotel promoters and by Port authorities, lagoon dredging for the construction of marinas and wide harbour works - all of which are activities that cause destruction of fragile ecosystems.
The situation is not different in Kenya. From last year, residents of the coastal town of Mombasa started panicking as they watched coral reefs suddenly disappearing and witnessed the sight of bleaching along the Indian Ocean beaches.
Experts blamed high ocean temperatures this year for the bleaching, as environmentalists tie it to climate change. This bleaching can also rob fish and other species important shelter and food sources.
According to a report by Kenya Wildlife Service, coral reefs provide refuge and food to nearly a quarter of all marine species, making them among the most biologically diverse habitats on the planet.
Threats from human activities like over-exploitation of resources, increased pressure on resources, land use patterns, pollution from boat engines, sedimentation, unplanned tourism and urban development have affected corals, which used to provide food and income to coastal communities.
Pollution also comes in the form of waste discharge into the oceans, which triggers change in water quality thus contaminating corals.
Siltation resulting from deforestation and upsurges in contesting algae due to sewage, and overfishing in the lagoons are reducing growth rates of corals massively.
Tourists who flock our oceans during summer also threaten our corals courtesy of their sun-block creams which contaminates water.
“Solar cream which is used by tourists has equally been linked to chemical contamination of sea water and coral death in certain areas as with UV (ultra-violet)and ozone layer thickness equally affects the life of corals which may bleach and die,” Mr Kauppaymuthoo said.
Additionally, these factors diminish the resilience of the corals to temperature increases, snowballing the prospect of coral bleaching and potential death further, which has been occurring on a prolific scale along African coasts for quite some time.
“Corals represent our past; they were among the first living organisms on earth and our future as the base of the marine food chain. Failure to consider seriously the current state of degradation and to curb the current trend would be a critical move for humanity,” he added.
The intensifying sea levels cover corals that break down the energy of waves and squalls.
Branching corals flourish much faster and provide the majority of coral rubble that replenishes the sand within the lagoons along African coast and islands.
However, physical collision caused by contact with boats, anchors, anglers, snorkelers and divers harm even the massive and encrusting corals.
With their ability to host a variety of algal types, each with different sensitivities to environmental stress, corals can still survive in the face of global climate change. This indicates that apart from environmental factors, it is human activity that is affecting the corals more, thus the need for its conservation.
Conservation of reefs will go a long way not to only preserve the breathtaking scenes on the African coastline but also reduce sea urchins and biomass.
Thus, the call for protection need not to stem from its importance to coastal people alone but to our countries since it provides goods and services that are the mainstay of some economies - tourism and fisheries.
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