Folks get ready for a snorkel near Cano Island in Costa Rica. See other beautiful phenomena from Costa Rica.
Man and the reefs.
Coral reefs play an important role to life on earth that very few people know about. Osha Gray Davidson's book, The Enchanted Braid brings to light this unique and fragile ecosystem.
Coral reefs are a great source of food essential to life on earth. They play host to a variety of fish and fish nurseries. They have been identified to have medicinal properties such as being used as a bone graft substitute. The reefs fix calcium for the entire marine ecosystem and alter the landscapes on coastlines.
The coral reefs have been equated to the rainforests on land in terms of the great biodiversity that they harbor. However nutrient and sediment loading, global warming, over-fishing and destructive fishing practices are some of the problems facing this fragile ecosystem. Other havocs to the coral reefs are destructive hurricanes.
While research has shown that coral reefs develop resilience and recovery from destructive natural elements like hurricanes and strong ocean currents (Lugo et-al), the major threat in my opinion are thus the relentless anthropogenic impacts.
Though some governments and scientist argue that global warming is a natural cycle that has occurred previously, there are no doubts that the current high levels of CO2 in the atmosphere is the work of man. Through combustion of fossil fuels and deforestation the levels of CO2 have increased by nearly one-third over the past century (Davidson pg 191). Coral bleaching has been attributed to the earthÕsÕ mean temperature rise of between one and two degrees. This is because corals and very sensitive to changes in sea temperatures, and sea levels.
Over-harvesting of fish and other for live reef fish trades such as for the Napoleon wrasse leads to disruption in the balance of the fish in the reefs. Wrasse and other fishes play an important role in keeping in check the thriving of algae that would otherwise smother the coral reefs. Each species in the coral reefs plays a role in the health of the coral reef ecology. Elimination or imbalances in one thus affects the whole ecosystem.
Destructive fishing practices by man are also a major threat to the coral reefs. There is the blast fishing through detonation of explosives that not only directly destroys the structure of the coral reefs but also indiscriminately kills scores of fish and corals and other inhabitants of the reefs that are all key to a healthy coral ecosystem. Another destructive fishing practice is cyanide fishing as practiced in countries like the Philippines. This is a practice mainly used to provide ornamental fish for the international aquarium trade. Cyanide fishing is known to wipe out every living creature in the area where it has been emptied including the corals.
Like the strands in a spider web, coral reefs cannot survive alone. There exists an intricate connection between coral reefs, sea-grass and mangrove ecosystems. A threat to any of these three spells doom for the others. Mangroves and sea-grasses are highly evolved marine communities that survive the toxic saltwater. They both play an important role as buffer zones between the fragile coral reefs and land based nutrients and pollutants. Mangroves and sea-grasses through absorption of these nutrients and sediments hence lower the nitrogen and phosphorous levels in the reef waters. A low nitrogen and phosphorous level stifles the abundance of algae which would otherwise smother the corals. In addition the sea-grass blades act as bumps that reduce the high speed of ocean currents and waves that would otherwise be directly destructive to the coral reefs. However these two essential components of the marine ecosystem are also threatened by man.
There is the indiscriminate harvesting of mangroves for timber, or the destruction of mangrove forests to pave way for shrimp farming that is on a high increase. In addition there is high pollution levels and sediments from land based erosion and the pesticides from the shrimp and other agricultural farming practices. Sea-grass is also threatened by blast and cyanide fishing practices that drag nets across them hence destroying them.
Oil spills and other marine accidents such as happened within an eighteen-day period whereby three ships ran aground in the Key Largo National Marine Sanctuary in 1989 are threats to coral reefs.
In conclusion it is n doubt that the main conservation efforts to try and save coral reefs should be focused on reducing the human induced effects. More than half of the coral reefs around the world have been savaged variously by over-harvesting and rising temperatures which are mainly human induced (Wilson, 2002). Coral reefs themselves are known to be interlinked that the destruction of one could spell doom for the entire coral reefs in the world (Davidson, 1998). As noted earlier reefs have been known to recover from natural hazards but they can't keep up with the anthropogenic effects.
Davidson, O. G The Enchanted Braid. Coming to terms with Nature on the Coral Reef. New York, NY: John Wiley & Sons, Inc. 1998.
Lugo, A. E, Rogers, C. S and Nixon S. W. Hurricanes, Coral Reefs and Rainforests: Resistance ruin and Recovery in the Caribbean. Oct 1999.
Wilson, E. D, 2002. The Future of Life. New York, NY: Alfred A. Knopf.
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