As climate change concerns pose a series of threats to the global community, costal nations like Sri Lanka are further impacted by the multiple threats to their marine ecosystems.

Chief among the climate change concerns are the world’s coral reefs, home to some 25% of marine species worldwide, covering only 0.2% of the ocean floor.

Scientists claim that the corals would recover and regenerate, if there is less contamination and less pollution that devastatingly impact these fragile ecosystems. But contamination and coastal pollution are among key factors destroying natural ecosystems, specially in developing countries which are natural resources dependent for many reasons including economic.

Corals are also receiving importance post tsunami, as their value as a natural buffer is being re-evaluated. Hence their presence calls for fresh studies and for regeneration programmes.

According to Global Programme Action (GPA) for the Protection of the Marine Environment from Land-Based Sources, preventing coastal pollution is key to aiding coral recovery.

Scientists submit the view that the ability of coral reefs to survive global warming would largely depend upon the levels of pollution to which they are exposed.
Having studied reefs that were bleached in the late 1990s by high surface sea temperatures, they claim a link exists between recovery rates and the levels of contamination entering coastal waters due to land based developmental activities.

The findings were made public at an international marine pollution conference in Beijing last year which recorded that reefs had shown ability to speedily recover where pollution levels, dredging and other kinds of human-induced disturbances were significantly low.

Climate scientists also worry about land based developmental activities as an impediment to conservation and growth of corals. According to their estimates, up to 90% of the tropical coasts the world over could be developed by 2030. This means additional stress on the reef floors.

The new studies indicate that healthy ecosystems exposed to minimal contamination are likely to recover and survive better than those stressed by pollution, dredging and other human-made impacts.

Marine environments tend to suffer tremendous pollution for a variety of reasons. These range from public health concerns, tourism related activities, over fishing and regular fisheries. Weakened in many ways, the onslaught of climate change is something most corals find difficult to survive against.

According to a publication launched at the third International Tropical Marine Ecosystem Managers Symposium, Mexico, an estimated 16% of the world coral reefs have suffered around 90% mortality due to severe bleaching.
Amongst the more seriously damaged are reefs across the Indian Ocean including around the Comoros, La Reunion, Madagascar, Mauritius and the Seychelles.

Research scientists submit that cleaner and less disturbed, coastal waters aid continued coral recovery and recolonisation which is what coral conservators wish to achieve in the next few years.
Across Asia the problem is aided by the fact that mangroves, yet another significant natural shield, are being cleared to pave the way for coastal development.

It has also been recorded that the Indo-Pacific Region holds nearly 92% of the world’s coral reefs, the rest are mainly in the Caribbean and West Asia sites like the Persian Gulf.

The report claims that over the last 30 years, coastal development of roads, settlements and resorts have developed dramatically, reducing coastal vegetation, discharging increased levels of sewage into the coastal areas and impacting the ecosystems upon which millions, if not billions, depend for food, materials and livelihoods.

In Asia and Eastern Africa, up to 90% of the sewage is discharged directly into rivers and the sea. While coral reefs may tolerate a little pollution, they have great problems recovering from bleaching events in polluted waters, as dead coral reefs easily are eroded by waves or get covered in algae that thrive on the nutrients in sewage.

Corals are extremely sensitive and may react to just a few percent of what is considered unhealthy nutrients in water, adds the report.

There is also concern that while coral reefs may change with climate stress, they can actually die entirely with the combined actions of pollution, sedimentation and over fishing.

Corals possess a natural resilience to changing environments and ability to recover.

In the Seychelles, Acropora corals seemed to have survived mainly in sites with either cooler water, more current and in sites less exposed to development and pollution on the east coast.

The results confirm findings and claims worldwide, that land-based pollution, reclamation, clearing of coastal vegetation and poor sewage control can damage reefs.
More importantly, they demonstrate that protection of coastal land areas around marine protected areas is essential for reducing local pollution and facilitating re-colonisation of corals, the findings add.

Coral reefs support over one million plant and animal species and are perhaps among the most diverse ecosystems in the world.