MK Nature Design is concerned about the coral reefs in the oceans. They are bleaching. What does this mean and what is really happening?
The coral is a symbiotic relationship between the coral polyp and algae. The algae photosynthesizes and produces food and energy for the polyp. The coral polyp can also eat zooplankton. The polyps provide a hard structure (they exude calcium carbonate that creates a skeleton) and carbon dioxide for the algae. The algae provides the spectacular color to the coral, most corals are clear and colorless. Some coral colonies are only one sex and produce only sperm and then rely on another colony to provide the eggs. Krill eat the polyps and then seals and whales eat the krill. So the coral reefs are vital for the survival of larger mammals and species in the oceans.
Corals are found off the Aleutian islands of the coast of Alaska all the way down to the Caribbean sea. The biggest ones are found in the tropics and subtropics where they grow quickly.
Most of the corals found today are between 5,000 and 10,000 years old. Approximately 25% of marine species rely on the corral for food, shelter and breeding. They are known as the rainforest of the sea, being extremely diverse.
Coral reefs are in danger due to acidification of the seas. As CO2 is released to the atmosphere due to man’s burning of fossil fuels, the CO2 is absorbed by the oceans causing acidification. Acidification results in a decrease in the corrals ability to make the exoskeletons required for survival. Water pollution is having an effect as well. Agricultural pesticides and fertilizers, oil and gas, sewage discharge and high sediment loads due to erosion kill off the coral reefs. As temperatures increase due to global warming, the coral polyp excretes the symbiotic algae and dies off. Fishing with cyanide gas, blast fishing and fishing with trawlers can also destroy the corral reefs.
The largest coral reef is the Great Barrier Reef in Australia. It is 1500 mi (2400 km) long. It is reported that over 90% of the reef is bleaching. The coral reef supports fish stock that provides food for over 1 billion people. Some of the coral reef is reported as dead.
It is believed that heat stress due to a recent El-Nino combined with climate change is what is bleaching corals today. High heat and bright sunshine cause the metabolism of the algae to speed out of control and they produce toxins. The polyp then exudes the algae resulting in a bleaching effect. If temperatures drop, the coral can recuperate but is vulnerable to disease. When heat stress continues, the polyp of the coral starves to death.
A large underwater heat wave formed in 2014 in the northeastern Pacific. This wave slowly affected corals. In 2015 the most powerful El-Nino in a century affected corals in the tropical and southern Pacific.
Reefs that take centuries to form can be destroyed in weeks. Repeated bleaching will result in the death of the coral. Bleaching has been reported in Australia, Hawaii and Florida. Although the El-Nino effect is expected to decrease in 2017, we need to be concerned in 2016.
Climate warming is happening due to increased CO2 and methane emissions that are caused by man. One of the worst polluters is the burning of fossil fuels. People may think that corals are not important but they indirectly feed 1 billion people. It is time to wake up and strongly encourage renewable energy. One of the most important, slow growing food sources of the ocean is dying. Please act now!
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