From the shores of Florida to southern Japan, from the Midway atoll to the turquoise blue waters of Australia, corals adorn a lot of our ocean like priceless jewellery.

Found in more than 100 countries around the world, most reefs are located between the Tropics of Cancer and Capricorn although there exist cold water and deep water reefs; one of the most bizarre is a reef some 300-400 metres (980-1,310 feet) deep located inside the Arctic Circle!

Believed to have the highest biodiversity of any ecosystem on the planet – even more than a tropical rainforest – reefs occupy less than one percent of the ocean floor but are home to more than twenty-five percent of marine life.

This World Oceans Day (June 8), we're taking a closer look at these delicate ocean ecosystems and their importance to biodiversity. Corals have been hit hard in recent decades, with scientists finding all types of corals declining across the world's largest reef systems. Although World Oceans Day celebrations are largely virtual this year, the importance of this day is timelier than ever.

What are coral reefs?

Coral reefs are built by and made up of hundreds to thousands of tiny animals – coral polyps – that are related to anemones and jellyfish. Each soft-bodied polyp has a hard outer skeleton of limestone (calcium carbonate) that attaches either to a rock or to the skeletons of other polyps, creating the structures we have come to love.

Coral reefs are built by and made up of hundreds to thousands of tiny animals called coral polyps. Image © pakmat

Most corals contain an algae called zooxanthellae, which use the coral's skeleton as a cozy home but also use their metabolic waste products for photosynthesis. The corals, in turn, benefit from the zooxanthellae creating oxygen, removing wastes, and helping the corals grow, thrive, and build up to a spectacular reef.

Why are they important?

Coral reefs not only act as homes and/or nurseries to numerous fish species, but they also protect coastlines from storms and erosion, and may hold the key to creating new medicines. Over half a billion people depend on coral reefs as a source of food, income, and protection.

What threats do they face?

Coral reefs face a slew of threats from climate change, destruction (e.g. coastal development, dredging, quarrying, destructive fishing practices, and boat anchors), sewage run-off, and natural disasters. Some experts say they will be gone by the middle of this century – the first great ecosystem casualty of the climate emergency.

Coral reef face a number of threats including warming oceans, pollution and habitat loss.

The near-global shuttering of the tourism industry due to the coronavirus (COVID-19) pandemic has allowed for some reefs to undergo a brief period of environmental healing. While coral reefs have taken a reprieve from being physically stepped on and combating damaging chemicals from sunscreen (like oxybenzone), they face a unique pollution problem: personal protective equipment (PPE) is now washing up on coral reefs around the world, like off the Philippines.

But the news is not entirely grim.

What is being done to protect them?

Numerous initiatives are actively restoring coral reefs on a massive scale, using science to further coral research and coral reef monitoring techniques. There are also other organisations dedicated to educating the public on the importance of our oceans and coral reefs. Here are a few:

  • Coral Restoration: Since 2007, the team from Coral Restoration has returned more than 130,000 critically endangered corals back to Florida's reefs through collaborations with universities, aquariums, NGOs, and government agencies including the NOAA (National Oceanic and Atmospheric Adminstration) and the Florida Keys National Marine Sanctuary. 
  • Counting Coral: This organisation builds marine-grade stainless steel sculpture installations to help restore coral reefs. The structures are supposed to be the first stage of coral nurseries, and the organisation hopes to “collaborate internationally with governments to create marine protected areas, manage sites, and develop large super coral farms which will in turn support local restoration projects.”
  • Queensland Care Army for the Great Barrier Reef: The Australian Government has announced the details of a $3.2 million initiative that will see seventeen tourism operators along Queensland’s Great Barrier Reef conduct reef health and impact surveys. Carried out at 243 reef tourism sites, they will be dedicated to growing and out-planting coral, removing macroalgae, and helping control coral-eating crown-of-thorns starfish outbreaks.
  • Costa Rica Coral Restoration: This non-profit offers an incredible reef restoration program that participates in growing and planting coral to rebuild this critical part of our ocean environment.
Coral restoration projects are helping to rebuild coral colonies.

Unfortunately, movement restrictions due to the ongoing COVID-19 pandemic has prompted the end of some restoration projects, such as the Southern Leyte Coral Reef Conservation Project (SLRCP). The hope is that in the coming years these will be able to restart.

Check out #WorldOceansDay (and #WorldReefDay from earlier this month) on social media to learn more about the endless initiatives working on coral reef conservation and regeneration that are playing a big role in saving our world’s corals for future generations.

Header image: NOAA