Many factors play a role in the devastating threat to the world's coral reefs with the greatest threat being that of man himself. Human users are stressing the delicate balance of life within the coral reef by bringing poor management, over pollution, uncontrolled tourism and fishing both pleasure and commercial. Along with the many environmental issues affecting the coral reefs are the threat of global warming and coral bleaching, which all upset the reef's ecosystem creating natural breaks in the food chain imbalance leading to harmful predator success.
Indirectly human lifestyle is stressing the globe in more ways than the obvious. Pollution brings poor water quality, which in turn affects the light and oxygen having a great impact on not only the algae but all organisms within the reef. Present not just at the reef's water but pollution is also sourced from upstream in the rivers where farm-runoff flows downstream bringing fertilizers and chemicals working their way into the sea, supporting a harmful algae growth and endangering the reef's vulnerable and endangered food chain.
Man's negative contributions to global warming aid in the rising sea temperatures, changes to the earth's ultraviolet light and ocean acidification and are all altering the volatile world of under-sea life. The industry of commercial coral mining for cheap rock is also gravely destroying the delicate balance of the coral reef. As key high demand members within the delicate food chain are depleted and upsetting the balance of prey and predator in the reef food chain, many unwanted dolphins and turtles are trapped in the nets and perish. Saltwater aquarium fishing to supply world hobbyist also has a large impact on the hundreds of species being unethically chemically drugged and plucked from the reefs and imported annually leaving behind reef damaging chemical kills.
The pollution from the boats, both industry and tourism, is also affecting water quality and introducing disease, contaminating the area with damaging chemicals such as phosphates and nitrates, both negative by-products of the shipping world. Organic pollutants through mismanaged land development, run-off, and building of roads and channels for island access and docking, all blow soil and sand around the globe introducing dust to the algae bloom and take up available oxygen depleting the supply to the sea life and contributing to the decline in health of the coral reefs. Sewage unfiltered into the sea as well as oil and chemical dumps are also deadly factors in the death of the reefs, as are mining and mineral waste free flowing into waterways which lead into the seas.
The ocean's acidity levels have altered due to the global problem of increasing CO2 emissions, resulting in decreased pH levels reducing the calcification of the weakening corals. The seagrass beds are also being depleted in the pollution of the oceans and with that the water quality is declining and the reef life is suffering. Increased coral diseases, including Coral Bleaching, have had a grave threat on struggling reefs now battling the many spreading parasitic, non-infectious, environmental, reproductive, bacterial and genetic diseases attacking daily and compromising not only the balance but the very future of the coral communities.
How humans will choose to oversee these debilitating factors and control the threats to this ecosystem balance in the sea will be the success or the demise of the world's delicate coral reefs.