Endangered corals
Eversince a colleague at work told me about his salt water water aquarium he had built himself so as it would fit into an old TV frame, I was fascinated by the pictures he showed of colorful fish and corals. When he turned up one day with a piece of dead coral, I found that very sad, but also intriguing. It somehow reminded me of Lot's wife who looked back at the city of Sodom when this got destroyed and subsequently turned into a pillar of salt, a remnants/ruins of an ancient city.
These remains, hard and rigid, bleached, of what was a living organism, stand as a memorial or warning sign to us and remind us that we have to take care not to destroy our corals reefs.
The following text is just a short amount of information gathered and is by far not complete. It was important for me to take time to read a minimum on the subject, to "digest" and absorb it, to become emotionally involved enough to be able to do something holeheartedly. One documentary that certainly helped was "Chasing Corals" which you can see on Netflix and Youtube. It moved me to tears.
Reefs are sometimes called the rainforests of the sea. They provide very important habitat for a quarter of ocean animals, algae and sponges . Their importance for humans are indeniable, thus their vicinity to the coasts protect these from hurricances. The provide food for the inhabitants living near the coast.
As John Kerry, former Secretary of State, stated in 2016: ...our ocean is absolutely essential for life itself-not just the food, but the oxygen and weather cycles of the planet, all depend on the ocean. The ocean is under tremendous pressure form human activity-including unsustainable and illegal fishing marine pollution, and climate-related impacts.
Coral Ecosystem is a fragile one which can easily be disrupted.
Corals can be found in all seas, even in colder waters from, Norway, Scotland, Ireland to Spain. Coral Reefs however as we know them are only found in warmer, subtropical waters where water temperatures remain between 20 and 30 degrees the whole year. They need clear water necessary for the photosynthesis for their symbiotic algae, moderate water movement, no fast growing algae, strong underground and free room to grow.
These necessary conditions make clear how fragile this ecological balance is, as any changes can disturb it and stress the corals. Stressed corals (for some reason which is not yet known) evict their algae which are partly responsible for their color. They bleach which doesn't mean that they are dead yet, but they will die without their algae to help to "feed" them. This means that the soft tissue of the corals will disintegrate and rot away, a very sad sight as some videos show. Only the skeletons will remain.
Symbiotic relationship with algae
It is said, that corals resemble to flowers during the day and to animals during the night as they reach out their tentacles for food. "Algae belonging to the group known as dinoflagellates live inside the corals'tissues. The algae use photosythesis to produce nutrients, many of which they pass to the corals' cells. The corals in turn emit waste products in the form of ammonium, which the algae consume as a nutrient. This relationship keeps the nutrients recycling within the coral rather than drifting away in ocean currents and can greatly increase the coral's food supply. Symbiosis also helps build reefs-corals that host algae can deposit calcium carbonate, the hard skeleton that forms the reefs, up to 10 times faster than non-symbiotic corals." (source Princeton University)
Reproduction of corals
There are several ways for corals to reproduce
- sexual reproduction by corals themselves or use of coral larvae being put out in water zones favoring their settling
- use of coral fragments "fixed" to a hard substrate
Bioerosion
Bioerosion (external and internal) is a natural process during which coral rubble helps to solidify the reef structure. A reef can only survive if the production of lime is superior to the abrasion.
The importance of corals for humans
- Reef limestone gets used in the construction sector
- Coral reefs protect the coasts from hurricanes and are groynes that prevent the erosion and land runoff of the coasts
- 1/4 of fishing in developing countries comes from the reefs
- "Coral reefs are storehouses of genetic resources with vast medicinal potential"
- Tourism: development of the diving "industry"
Why are coral reefs destroyed
Local threatening:
- sedimentation, deforestation of rain forests and mangroves, use of reef material in construction, building on top of the reefs, all this causing land runoff, sedimentation, increase of additional nutrients which cause too much algae growth that "overrun" the corals
- Destructive fishing (use of dynamite)
- too much tourism lnked with water pollution, too much diving tourism
- scars on the reefs due to ship accidents, damages done by anchors, oil catastrophies...
Environmental impacts
Rise of water temperatures
rise of water level: this will cause the reefs to literally drown as the corals need to be near to the water surface to get light
acidification of the seas destroying the lime of the corals
What can be done
This is quite obvious and I don't want to go too much into detail.
Reduction of CO2 is essential.
Protection of the reefs on a local level might probably not save the corals but keeps the option of doing so. There are certainly also economical reasons why certain countries can afford to invest in the protection of their reefs.
Active measures of "repairing": transplantation of pieces of stone corals on the ocean ground (very costy and labour intensive)
ERCON-Electrochemical Reef Construction: a wire matrix put under direct current which causes the formation of calciumcarbonate crusts . This serves as an underground for pieces of corals to be fixed to.
SECORE: International Conservation Program: zoological garden, aquariums.. are producing coral larvae which is then brought into the damaged areas of the reefs
The part sports divers play in the protection of the reefs is ambivalent as the follow the development of the reefs and help with the mapping of these.
Even if the reefs regenerate, they would never regain their original level.
