Coral reef systems are home to some of the largest concentrations of biodiversity in the world, but climate change is putting them at risk.
Fish swimming through coral reefs in Panama. Thinkpanama. CC BY-NC 2.0
Home to countless fish and vibrant aquaflora, these awe-inspiring reefs are feeling the impacts of climate change.
To dive into the world of coral reefs is to experience an underwater garden defined by vibrant colors, rare plant life, and unparalleled biodiversity. Not only are coral reefs visually stunning and awe-inspiring, but they serve an important role in food systems and economic growth, as approximately one billion people rely on coral reefs across their world for food and income.
However, the effects of climate change are damaging the health and vitality of reef systems. One major effect of rising water temperatures on coral reefs is coral bleaching. Coral bleaching occurs as an adaptive response to warming waters, during which corals shed their symbiotic algae, or zooxanthellae, in the hopes of replacing it with algae that is more heat tolerant, a process that leads the corals to take on a white color and appear ‘bleached.’ This doesn’t immediately kill the coral, but the environmental keystone is left vulnerable and its death rate increases. With so many species relying on reefs as a source of nutrients and shelter, bleaching not only affects the health of the coral itself but the entire network of life that the reefs support.
The impacts of coral bleaching are increasing steadily alongside rising temperatures, with an ocean heat wave causing roughly 75% of the world’s reefs to experience bleaching between 2014 and 2017.
As reefs around the world feel the effects of climate change, now more than ever is it crucial to understand and appreciate the beauty and significance of coral reef systems around the world, as well as the efforts being made to protect them.
Great Barrier Reef, Australia
The Agincourt Reef in the Great Barrier Reef. Robert Linsdell. CC BY 2.0
Perhaps the most famous of all coral reefs, the Great Barrier Reef is also the largest coral reef system in the world, stretching some 348,000 square kilometers along the Australian coast. Home to distinct ecology and biodiversity, the reef holds roughly 400 distinct types of coral, 1,500 different species of fish, and around 240 different species of birds. The Great Barrier Reef is one of the most popular tourism destinations in Australia, with some 2 million people visiting the Marine Park each year.
Around 344,400 square kilometers or about 99% of the reef is included as part of the Great Barrier Reef Marine Park. As part of The Reef 2050 Long-Term Sustainability Plan, the Australian government invested $260 million into the park in an effort to aid reef protection and conservation efforts. The Great Barrier Reef Marine Park Authority has also taken strides to acknowledge Indigenous communities’ relationships to the reef and reserves specific marine tourism permits that offer opportunities for Indigenous people to build tourism businesses and collaborate with other operators to share their cultural connection with the reefs.
In 1981, the Great Barrier Reef became a World Heritage Site, an area that is granted legal protection by the United Nations Education, Scientific and Cultural Organization (UNESCO), making it the most biodiverse ecological area to be included in the category.
Despite such protections, the Great Barrier Reef is vulnerable to harmful bleaching practices, with nearly 400,000 hectares disappearing due to bleaching between 2015 and 2016 alone. As outlined in The Reef 2050 Plan, the Australian Government aims to reduce the nutrients loads entering the ocean via rivers by 80% by 2025.
The Great Barrier Reef is one of the most popular diving destinations, and offers travelers the experience to glimpse a range of marine life, from whitetip sharks to yellow snappers. The town of Cairns is a popular entry point and has a bustling hostel season in peak diving season during which day boats take divers out to nearby reefs. If travelers want to escape the crowds they can venture farther north to Port Douglas and utilize the town's diving resort options. Because the quality of reefs increases as one moves further from the mainland, divers frequently utilize liveaboard trips, which allow them to spend multiple days and nights living on a boat that transports them to different diving sites. While diving is possible year-round, Australia’s summer months between December and February bring in warmer and clearer water to talk in the stunning vibrancy of the corals. However, during the winter months from March to November (the Southern Hemisphere’s de facto summer), divers are more likely to come across large marine mammals. The Great Barrier Reef is suitable for divers at all levels, though degrees of difficulty vary depending on the site, with spots such as the Osprey and Ribbon Reef being more suitable for advanced divers.
Raja Ampat, Indonesia
Colorful corals and fish at the Raja Ampat. Carlos Fernandez-Cid. CC BY 2.0
As part of The Coral Triangle, an oceanic ecological area in Southeast Asia and the Pacific, the Raja Ampat reef stretches nearly 4 million square miles. The rich nutrients and biodiversity of this area makes it home to 1,600 different fish species and 75% of the world’s coral species. The diversity in the area in part stems from the area's proximity to the “Ring of Fire”, a range of underwater volcanoes that extends for some 25,000 miles along the Pacific Ocean. Stretching along the boundaries of several tectonic plates, the area is rich in volcanic activity, and holds 75% of the Earth’s volcanoes, of which it has more than 450.
Parts of the Raja Ampat are included in the network of Marine Protected Areas that was established by local communities and governments along with Conservation International, The Nature Conservancy, and Worldwide Fund For Nature, to provide conservation and zone regulations to a total of 2,000,109 hectares.
The Raja Ampat has proven widely resilient to the effect of climate change and warming waters. The reef’s unique location has rendered it adaptable to a variety of different climates, with low tide reefs heated by the sun and deep ocean reefs that experience oceanographic upwellings which bring in cold, nutrient rich water. Temperatures across The Raja Ampart can range between 66 degrees to 96 degrees Fahrenheit. Because coral bleaching is a stress response to climate change, The Raja Ampat reefs resilience to intense warm water temperatures also means that the reef system has exhibited few signs of bleaching.
Due to its remote locale, the Raja Ampat is less popular with divers than some of the other major reef systems. But those who choose to embark on the journey will not be disappointed. Liveaboarding is the most popular way to see the reefs, with around 40 liveaboards in the area, and trips are on offer from October to May. Dive resorts are also popular for visitors who want a land-based option. Some of the most popular diving spots include Sardine's Reef, Mike's Point and Blue Magic, located at the Dampier Strait. Along with its coral, the Raja Ampat contains a plethora of rich marine life including reef sharks, barracudas, and octopuses. With such diversity, it's no wonder the Raja Ampat reef holds the record for the largest number of different species recorded in a single dive.
Red Sea Coral Reefs, Indian Ocean
Divers in the Red Sea near Big Brother Island. Derek Keats. CC BY 2.0
The Red Sea Coral Reefs are defined by their distinct location and geological history. The reef platforms are over 5,000 years old and extend for some 1,240 miles (2,000 km). Due to its unique location and regional climate, the Red Sea reefs are tolerant to extreme climates, including high temperatures, salinity, and frequent turbidity from seasonal dust storms. A lack of river discharge, combined with low rainfall in the region helps make the water exceptionally clear and free of heavy sediments. This unique geology makes the Red Sea Reefs an ideal home for rare species, with roughly 10% of its 1,200 recorded fish species being endemic, meaning that they are found nowhere else.
The Red Sea Coral reefs are unique in their resistance to climate change and ocean bleaching. This resistance is in part due to the fact that many of the reefs in the Red Sea actually migrated to their current location from the south, an area with significantly higher temperatures. Relying on their historical comfort with extreme heat, today, reefs in the Red Sea seem to be actively thriving as water temperatures rise, with algae doubling the amount of oxygen they produce. In order to learn more about the Red Sea reefs’ ability to thrive in such extreme weathers, scientists have built a Red Sea Stimulator to try and mimic the conditions of the area and understand how the specific environment in the Red Sea can be used to help protect other reef systems that are not as resistance to climate change.
While the Red Sea coral reefs have proven resilient to climate change, they face the threat of degradation from nearby urban expansion that can create runoff and debris harmful to the water quality. In 1994, the governments of Israel and Jordan collaborated to found the Red Sea Marine Peace Park, in the Gulf of Aqaba. The park offers a groundbreaking example of a cross-national collaboration to preserve and protect coral reefs.
Diving the Red Sea allows an opportunity not just to see the coral, but also large marine mammals such as sharks and dolphins, unique underwater environments including labyrinths and lagoons, and remnants of past shipwrecks, including the SS Thistlegorm, a British cargo steamship that sunk in 1941. Most dive resorts can be found in the coastal towns of Sharm el Sheikh and Dahab. The Red Sea’s high evaporation rates and infrequent rainfall and isolated location make it a nearly year-round diving destination. Diving in the northern region allows opportunities to explore the lagoons of El Gouna and shipwrecks found in the Straits of Gubal. In the South, the Fury Shoals is perfect for gentle drift dives, and the Zabargad and Rocky Islands house shallow reefs and black coral trees. The St. John’s Reef on the border of Sudan is one of the more isolated regions of the Red Sea. Divers can explore pristine caves and tunnels, however choppy winds between October and April can cause harsh conditions.
Rainbow Reef, Fiji
Fish swimming in Fiji’s Rainbow reef. David Burdick. CC BY-NC-ND 2.0
Located in the Somosomo Strait, a passageway that separates the Taveuni and Vanua Levu islands in Fiji, the Rainbow Reef offers a striking spectrum of colors that live up to its name. The Rainbow Reef is often called the soft coral capital of the world, and one of its most popular reefs is the Great White Wall, an underwater slope covered in a tapestry of soft white corals and home to countless colorful anthias as well as reef sharks and manta rays.
Fiji’s reefs have also been impacted by rising temperatures and bleaching. In 2017, a major bleaching event killed nearly half of Australia’s Great Barrier Reef and affected almost all of the reef’s protected by UNESCO as World Heritage Sites. As a reaction to the devastating bleaching, Fijian Prime Minister Frank Bainimarama called for greater protection of reefs as they face the triple manmade threats of ocean acidification, rising temperatures, and harmful fishing practices. In January 2018, the Fijian government banned the sale of live coral, in an effort to provide further protection of the coral systems and recognize the important role these reefs play for local Fijians who rely on them for food and economic stability.
The Rainbow Reef is a popular diving spot, with the Great White Wall being included as one of the top 10 diving destinations by U.S. Divers Magazine and there are a few different diving resorts in the area. Most diving is done through resorts as there is only one liveaboard in Fiji. One of the most popular diving spots is Annie's Bommies, located between the Taveuni and Vanua Levu islands. The ‘bommies’ refer to the three submerged coral reefs that provide the perfect passageways for divers to weave between and catch a glimpse of the schools of fish, eels, leopard sharks and the stunning hues of the opal bubble coral. The best visibility for diving along the Somosomo Strait occurs from April to October, with the winter season from July to September ushering in choppier water conditions.
Jessica Blatt
Jessica graduated from Barnard College with a degree in English. Along with journalism, she is passionate about creative writing and storytelling that inspires readers to engage with the world around them. She hopes to share her love for travel and learning about new cultures through her work.