World’s Largest Coral Discovered!

It’s older than the United States… it’s so huge it’s visible from space… and it’s alive! Scientists have discovered the world’s largest coral in the southwest Pacific Ocean, and its remarkable size and survival is a bright spot of hope in a widespread pattern of coral decline (Paddison, 2024). Researchers from National Geographic’s Pristine Seas team found the colossal coral on an expedition to the Solomon Islands, and it was first encountered by their underwater cinematographer Manu San Félix (Ogasa, 2024). After he alerted the rest of his team, scientists dove underwater in pairs of two to measure it, but it proved too large for their measuring tape (Paddison, 2024). Eventually, by keeping one diver in position at the tape’s end while the other leap-frogged ahead, they were able to accurately record its dimensions: 34 meters wide, 32 meters long and 6 meters tall (Ogasa, 2024)! Visible on satellite images and longer than a blue whale, the largest animal on the planet, this shattered the previous world record held by another coral known as “Big Momma,” which is 22 meters wide and located in American Samoa (Ogasa, 2024).

Corals are made up of a very large number of polyps, small animals that look like tiny sea anemones and grow over the course of centuries (Eli, 2024). Each distinct coral is considered to be a colony of genetically identical individual polyps, and groups of these colonies can form reefs (Eli, 2024). Though the newly discovered coral colony is not part of a multi-colony reef, it comprises almost 1 billion individual polyps estimated to have grown uninterrupted for 300 to 500 years (Ogasa, 2024). The Pristine Seas team also identified this colony as shoulder-blade coral (Pavona clavus), named because the ridges of its stony body look like scapulas (Ogasa, 2024). Although shallower reefs nearby had recently been degraded by warming waters, the team’s health assessment found that this colony was in excellent condition, making it a “beacon of hope” in a worrying trend of global coral decline (Eli, 2024).

Coral reef ecosystems are extremely important to the health of the marine world. They are considered biodiversity hotspots, supporting over 1 million aquatic species (Basic Information about Coral Reefs, 2017). They manage to sustain this extraordinary variety of life from such a comparatively miniscule area; Eric Brown, a Pristine Seas scientist, explained that these ecosystems hold more than 25 percent of marine species worldwide but cover only 0.2 percent of the entire ocean’s area (Ogasa, 2024). Coral reefs also provide a variety of ecosystem services, including protecting coastal infrastructure from intense waves and storms, and recreation opportunities like responsible snorkeling or scuba diving (Basic Information about Coral Reefs, 2017). Through maintaining both small-scale and commercial fisheries, these ecosystems act as an indirect food source for approximately 1 billion people, making them vital to countless communities around the world (Paddison, 2024). By acting as new sources of medicine, the species they support can even save lives. One reef-dwelling Caribbean sea sponge (Tectitethya crypta) produces substances that became the basis of cytarabine, a chemotherapy drug that stops cancer cells from replicating (Schwartsmann et al., 2001).

Despite all they do for oceans and our society, corals around the world face a variety of threats, most notably the effects of global climate change. Shifting climates can harm corals’ interactions with other organisms; most species have a mutualistic (mutually beneficial) relationship with microscopic algae (aquatic plants) living in their tissues, which helps provide nutrients and build up their calcium-based skeletons. Warming sea temperatures, however, cause thermal stress and lead them to expel those algae, exposing their white skeletons underneath in a process known as “bleaching” (Threats to Coral Reefs, 2022). Serious or particularly extended bleaching events can dramatically increase susceptibility to disease or even kill whole colonies outright. Currently, this process is the culprit behind the Great Barrier Reef’s record high coral mortality: losses of coral cover up to 72% have been attributed to high ocean temperatures and back-to-back cyclones worsened by climate change (Parts of Great Barrier Reef Dying, 2024).

The driving force behind climate change also harms corals in a different way: just as high greenhouse gas emissions fuel climate change, high amounts of carbon dioxide in the atmosphere fuel ocean acidification. When atmospheric carbon dioxide levels increase, the ocean correspondingly absorbs more of the gas to stay in equilibrium (a balanced state). This absorption changes the seawater’s chemistry, since carbon dioxide reacts to form carbonic acid and lowers the overall pH, making the seas more acidic. The continued burning of fossil fuels like oil, coal, and natural gas perpetuates the steady rise in atmospheric carbon dioxide, and the ocean ends up absorbing around a quarter of the carbon dioxide released in this way annually. Because of this, ocean acidity has increased by 30% since the start of the Industrial Revolution (Threats to Coral Reefs, 2022). More acidic seas, in turn, become less hospitable to coral, since there are fewer salts and ions dissolved in the water they can use to build their calcium carbonate skeletons. This slows their growth, and in severe cases, their skeletons may even start to dissolve.

Other anthropogenic (human-caused) threats to corals are more local, as most reefs are located in shallow waters close to shores (Threats to Coral Reefs, 2022). Though they act as important food sources for local communities, especially low-income and indigenous populations, patterns of overfishing can severely disrupt food webs. Some unsustainable fishing methods are especially destructive. In “blast fishing,” also known as “dynamite fishing” or “bomb fishing,” explosives are used to kill or stun schools of fish to ease their collection, and this practice can instantaneously turn healthy coral reefs into piles of rubble (Hampton-Smith et al., 2021). Though blast fishing is often outlawed, it is still practiced in many countries around the world. One review published in Biological Conservation concluded that well-enforced deterrence measures and the expansion of co-managed marine protected areas would be the most effective solutions to this problem (Hampton-Smith et al., 2021). Various avenues of land-sourced pollution also plague coastal reefs: dumped sediment, excess nutrients from fertilizers and wastewater treatment plants, herbicides, and trash like plastic bags or bottles can smother or sicken corals beyond recovery (Threats to Coral Reefs, 2022).

Coral conservation’s range of pressing challenges means that there is no one silver bullet solution, but employing a combined local and global approach is the best way forward. Simply increasing the amount of protected ocean would be a boon to coral survival and marine ecosystems as a whole. Currently, only 8.4% of the ocean is protected on some level, and scientists estimate that we need to protect no less than 30% to let the ocean continue absorbing emissions and supplying the world with food (Eli, 2024). This could involve expanding the scope of marine protected areas and improving fishing regulations to sustain both coral ecosystem health and traditional relationships with their local communities. On a global scale, we need a dramatic and immediate reduction in greenhouse gas emissions, or else the trend of warming and acidifying oceans will continue. Only if we implement these solutions can we hope to allow all corals a chance to grow with us into the future.

 

Works Cited

Basic Information about Coral Reefs. (2017, January 30). United States Environmental Protection Agency. https://www.epa.gov/coral-reefs/basic-information-about-coral-reefs

Eli, J. (2024). New Discovery: Largest Coral in the World Found in the Solomon Islands. National Geographic; National Geographic Society. https://news.nationalgeographic.org/new-discovery-largest-coral-in-the-world-found-in-the-solomon-islands/

Hampton-Smith, M., Bower, D.S., Mika, S. (2021). A Review of the Current Global Status of Blast Fishing: Causes, Implications and Solutions, Biological Conservation, Volume 262, 109307, ISSN 0006-3207, https://doi.org/10.1016/j.biocon.2021.109307. (https://www.sciencedirect.com/science/article/pii/S0006320721003591)

Ogasa, N. (2024, November 15). The World’s Largest Coral was Discovered in the South Pacific. Science News; Society for Science. https://www.sciencenews.org/article/world-largest-coral-solomon-islands

Paddison, L. (2024, November 14). Scientists Discover the World’s Largest Coral — So Big It Can Be Seen From Space. CNN. https://www.cnn.com/2024/11/14/climate/worlds-largest-coral-solomon-islands/index.html

Parts of Great Barrier Reef Dying at Record Rate, Alarmed Researchers Say; “Worst Fears” Confirmed. (2024, November 19). CBS News. https://www.cbsnews.com/news/great-barrier-reef-parts-dying-record-rate/

Schwartsmann, G., Brondani da Rocha, A., Berlinck, R.G., Jimeno, J. (April 2001). Marine Organisms as a Source of New Anticancer Agents. Lancet Oncology. 2 (4): 221–225. doi:10.1016/s1470-2045(00)00292-8. PMID 11905767.

Threats to Coral Reefs. (2022, April 13). United States Environmental Protection Agency. https://www.epa.gov/coral-reefs/threats-coral-reefs