The Crisis Of The Corals

Living in diverse historical communities; on the reefs, the corals fill the sea with colors; among small fish and crabs, the corals provide food and shelter to marine creatures.

Some people call coral reefs tropical ocean forests or ocean oases; this name means corals further enrich the sea nature in biodiversity with their properties and roles to preserve the environment. Coral reefs are teeming with life, covering less than 1% of the ocean floor, but are home to about 25% of all marine creatures.

Image 1: Coral reefs are home to a large amount of life in the sea.

While 12 percent of the world's fish production depends on coral, they are a symbol of geological wealth and cultural heritage. Environmental pollution has been a dangerous threat to corals, nowadays, most of the corals worldwide have been gone, and there is damage that could be irreparable.

Air pollution causes global warming; its consequences are the increase in sea temperature, which changes environmental conditions and reduces the chances of survival for the corals and their environment. The UN's World Meteorological Organization says the past ten years have been the warmest decade on record.

Emerging pollutants can impede coral growth and reproduction, disrupt overall ecological function, and cause disease and mortality in sensitive species. Scientific studies indicate that many stressors for the coral reef ecosystem originate from land-based sources, primarily toxins, sediments, and nutrients.

When sediment and other pollutants enter the water, they smother coral reefs, speed the growth of damaging algae, and lower water quality. Pollution can also make corals more susceptible to diseases; this can impede coral growth and reproduction; and cause changes in food structures on the reef.

Corals tend to aggregate in colonies, which are sources of corals in the world, some larger than others, all suffering from the effects of environmental pollution. Scientists assume that the larger the coral colony, the more resistant it is to the damages of pollution and global warming.

The great barrier reef

The Great Barrier Reef (Australia) is the most sizeable coral world reef system, stretching over 2300km; from ancient sea turtles, reef fish, and 134 species of sharks and rays; to 400 different hard and soft corals and a plethora of seaweeds.

Before 1995, the Great Barrier Reef was a thriving, biodiverse ecosystem. In 2017, the coral reef lost over half of its corals to climate change-related warming. In 2020, approximately 60 percent of the coral reefs were severely affected, and an additional 35 percent were mildly bleached. The severely affected corals have a total loss of their color.

This Australian ecosystem supports more than a quarter of all marine life, so its damage affects the entire world; scientific calculations show that 90% or all of the reefs could disappear by 2050 due to climate change and environmental pollution.

Even under the best of conditions, heavily damaged reefs take at least ten years to recover. The Great Barrier Reef, hit for so many years in a row, may never fully recover. The disappearance of coral reefs is giant; this has deteriorated the water in all the world's oceans. The loss of these places puts at risk the natural ecosystem of the sea; additionally, its consequences imply a decrease in the amount of fish available as food for people. In Image 2, gray areas are the dead corals.

Image 2: The largest coral reef in the world is heavily affected by damage that could be irreparable. 

Corals decline

Corals are considered animals, but they have a special requirement; to live, they must have a symbiotic relationship with microscopic marine algae that provide them with food, oxygen, and cleaning; they are called zooxanthellae.

The increase in temperatures causes stress that causes the corals to expel the algae from their tissues, which gives them a "bleach" appearance; the absence of the zooxanthellae is what strips the corals of their color, and without it, exposes their bright white skeleton. This process is called coral bleaching and affects corals worldwide and causes stress in the entire marine ecosystem.

Humans emit air pollutants that cause global warming; at the same time, global warming is responsible for increasing the ocean's temperature; if the water remains too hot for too long, the corals bleach and die.

The algae photosynthesize and deliver their products to the corals; as the principal food source is lost, the corals starve.

Farm pollution is one of the factors drivers of the Reef’s decline; it drowns out corals and seagrass beds and denies them sunlight, drives the crown of spiny starfish, and makes the coral more vulnerable to bleaching. Nitrogen run-off from farms can also lead to algal blooms, which starfish larvae feed on, promoting population explosions.

Coral reefs and the world face a surprising number of problems; initiatives and institutions have proposed solutions to protect these sites, but it has not been possible to achieve the necessary capacities to exercise a correct operation. 

Governments must help create laws that collaborate to remedy the damage in these environments, overfishing, and a host of other threats.

Image 3: A bleached coral, its properties are lost, leaving a lifeless solid body.

The coral areas have suffered the increase of industries and pollutant sources on the beaches near their surroundings without any regulation by the authorities, which further increases the risk for further damage.

The expansion of ports and vessels implies covering land within the sea, leads to dredging of the seabed, increased traffic at sea, and other disturbing impacts on the coastal and marine environment of these areas.

Mismanagement of commercial, recreational, and indigenous fisheries is increasing threats to many of the threatened species in various parts of the world, from corals to other endangered and protected animal species. Programs that ensure compliance with standards that respect nature must support  Fisheries management.

Eventually, the water becomes more and more acidic: coral reefs have difficulty building their limestone skeletons, then local problems arise; due to the consequences of shipping or excessive fertilization of the water due to the incorporation of too many nutrients from the ground.

When corals die, their skeleton remains solid, very resistant; Which serves as a growth site for algae that colonize dead coral skeletons. It could transform these places; initially, environmental conditions change and affect the lives of the animals that live there; It can disrupt the environment and fish, as many of these algae can be toxic. Additionally, it puts competition for the return of corals.

Rethinking our actions near these natural maritime paradises is fundamental for the earth and human beings. A possible solution to face this problem would be the transplantation of coral crops; these technologies exist; However, with high ocean temperatures, their survival could be compromised and limited.

It is our responsibility to help take care of this beautiful natural treasure and to remedy the damage we have caused; every day, the industrial processes destroy many animals and nature in the world. It is increasingly difficult to recover the damage, so now is the time to control while improving these processes.

References

• Goldberg, Walter. (2018). Coral Food, Feeding, Nutrition, and Secretion: A Review. 10.1007/978-3-319-92486-1_18. 

• Barton, Jonathan & Willis, Bette & Hutson, Kate. (2015). Coral propagation: a review of techniques for ornamental trade and reef restoration. Reviews in Aquaculture. 9. n/a-n/a. 10.1111/raq.12135. 

• Mallika Vasak. Medium Predict. Half of Australia’s Richest Ecosystem Is Dead. Mar 17 2021. Link https://medium.com/predict/half-of-australias-richest-ecosystem-is-dead-4bc1e536077a.

• WWF. Great barrier reef. Link https://www.wwf.org.au/what-we-do/oceans/great-barrier-reef#gs.331ndp.

• Prudent Press Agency. Marsh Tyler. Oceans: the Great Barrier Reef has lost half of the reef. March 21, 2021. Link https://www.prudentpressagency.com/oceans-the-great-barrier-reef-has-lost-half-of-the-reef/.

• Sydney Herald. Tony Moore. Barrier Reef took a ‘hammering’ but most replanted corals are surviving. March 19, 2021 — 11.00pm. Link https://www.smh.com.au/environment/sustainability/barrier-reef-took-a-hammering-but-most-replanted-corals-are-surviving-20210312-p57a9a.html.

• United Nations News. From the field: Saving corals in crisis. 19 March 2021. Climate and Environment. Link https://news.un.org/en/story/2021/03/1087592.

• Eurek Alert. Manoela Romanó de Orte. Algae growing on dead coral could paint a falsely rosy portrait of reef health. 17-MAR-2021. Link https://www.eurekalert.org/pub_releases/2021-03/cifs-ago031721.php.

• National Ocean Service. NOAA. How does land-based pollution threaten coral reefs?. 02/26/21. Link https://oceanservice.noaa.gov/facts/coral-pollution.html#:~:text=Impacts%20from%20land%2Dbased%20sources,and%20mortality%20in%20sensitive%20species.