Coral reefs are believed to have the highest biodiversity of any ecosystem on the planet. A great abundance and variety of species share this habitat, and even the tiniest organism plays a role.
Although coral reefs cover only one percent of the ocean floor, it is estimated that every fourth creature in the ocean calls the reefs home. Along with more than 4,000 types of fish, the reefs support sponges, shellfish, mollusks, starfish, turtles, sea snakes, and countless invertebrates—a total of more than one million species. Reefs are an important indicator of oceanic health, and they are sounding the alarm.
Since the 1980s, coral bleaching has caused widespread damage to reefs all around the world. Australia’s 2,300-km-long Great Barrier Reef has suffered extensive damage, with several kilometers of coral colonies that are dead or bleached completely white. Here, as on many other reefs, large sections of the once colorful underwater world have been destroyed and vanished.
The reason for this is steadily rising ocean temperatures, an indisputable effect of climate change. When the weather phenomenon “El Niño” becomes part of the equation, causing severe storms on land and increasing water temperatures along the west coast of South America every four years, the coral reefs don’t stand a chance.
The permanently elevated water temperatures, which have increased far beyond natural fluctuations, disturb the coexistence of the coral and the microscopic algae that, under normal conditions, settle on its surface and create its magnificent colors. This symbiotic relationship has advantages for both sides—the coral provides a safe habitat for the algae and the algae perform photosynthesis to produce oxygen and glucose that the coral needs to survive.
However, when water temperatures get too high (above 30 degrees Celsius) the microscopic algae become toxic and the corals expel them. This means that the corals not only lose their color, but also their basic requirements for survival—without algae there is no photosynthesis, and without photosynthesis there is no oxygen and no glucose.
Coral bleaching does not necessarily lead to coral death. If the heat wave lasts only a few weeks, the reef can regenerate. But even with fast-growing corals the regeneration process takes up to ten years. If the water is consistently too warm, there is almost no hope for the reef.
In addition to increased water temperatures, corals face another problem caused primarily by climate change—ocean acidification. As a consequence of burning fossil fuels, there are increased concentration levels of CO2 in the earth’s atmosphere and on the surface of the world’s oceans. The CO2 is absorbed by seawater, making it more acidic and decreasing the amount of carbonate ions in the water. As a result, it is much more difficult for corals to form a stable calcium carbonate skeleton structure.
Vamizi is one of the few coral reefs that has not yet been affected by these destructive problems, and it should remain so.
Researchers like Dr. Sylvia Earle are committed to establishing a network of marine protected areas. Similar to the conservation and protection provided by national parks, marine life in these HOPE SPOTS should live free from the impact of human activity.
You can find more information and an overview of already established as well as planned HOPE SPOTS on mission-blue.org.
