Let’s Talk Coral Reefs
Coral reefs are some of the most beautiful natural wonders of the world, and render positive effects on the economy. A study in 2002 published by the Journal of Marine Policy, stated the global economic value of the industry is $36 billion a year, $19 billion of which is derived from “on-reef” tourism such as diving, snorkeling, glass-bottom boating and wildlife watching on the reefs themselves. As one of the oldest and most diverse ecosystems on Earth, I can see why millions of humans would flock to see the underwater magic.
Outside of the economic stimulation, coral reef ecosystems support human needs in a variety of ways – subsistence/food, advances in 21st-century medicine, and shoreline protection against storm surges and waves.
As far as the ocean goes, coral reefs provide food and shelter for 25% of the ocean marine life, which is incredible considering reefs cover less than two percent of the ocean's bottom.
Despite all of the value to both human and marine life, coral reefs continue to face extinction, with an estimate that 90% will be extinct by 2030.
Why are coral reefs facing extinction, and how does it impact the ecosystem as a whole?
Coral bleaching
Coral bleaching occurs when the coral feels stressed by environmental changes such as warmer or colder water temperatures, sedimentation, elevated nutrients, causing them to expel their mutualistic symbiont zooxanthellae, resulting in the whitening of the colony and sometimes even death.
Sedimentation, caused by human activities like land clearing and coastal construction can lead to high rates of erosion and the destruction of reefs through burial. This smothers the reef and reduces light availability, which is required for the zooxanthellae to survive.
Elevated nutrients, which can also be caused by human activities such as wastewater from treatment facilities or runoff from lands in urban/farming areas, can cause algae blooms that shade the coral colonies, thus reducing the available light once again.
Ocean Acidification
Ocean acidification put into layman’s terms is a result of the increasing amount of carbon dioxide being absorbed into our oceans that causes the seawater to produce more carbonic acid, which increases the acidity of the water.
The rising acidity makes it more difficult for corals to build and maintain their skeletons, which are normally comprised of calcium carbonate.
Pollution
Plastic debris and microplastics can cause harm to the coral reefs from large pieces of plastic rubbing up against the coral and damaging the tissues to smaller, microplastics being ingested which can lead to diseases like black band disease, skeletal eroding band disease and white band disease.
Tourism
Scuba diving and snorkeling can cause physical damages, from the equipment grazing or hitting the reefs causing breakage to humans touching or accidentally stepping on the reefs. Additionally, divers and snorkelers can kick up sediments that can cause tissue damage or smother the reefs. All of which cause stress to the organism, which makes them more susceptible to diseases that can eventually lead to death. If a coral dies, the fish and other organisms that inhabit the coral lose their habitat, which makes them more vulnerable to predators.
Boating and anchors can cause breakage, fragmentation, or even dislodge corals. Anchoring can also damage surrounding habitats, all of which serve as nurseries and homes to a variety of coral reef organisms including fish. Thus, similar to above, the loss of coral can drive large shifts in the fish communities and trickle through the chain, eventually impacting the fisheries and consumers.
Fish feeding and human encounters with marine life can alter natural behavior, and change the home range size of coral reef species, population density, migration patterns, and reproductive activities.
How can you help protect the corals?
National Ocean Service has created a handy infographic which you can view below.
