Massive Coral Spawning Event Turns Dying Reef to "Super Reef," Resilient to El Niño and Pacific Ocean Warming Hot Spot in Kiribati

A marine biologist makes a long journey to investigate how a dying reef in an el niño-affected warming hot spot in the Pacific Ocean became a "super reef." It turns out to be a massive coral spawning event.

The coral reefs surrounding the five volcano tips that make up the Southern Line Islands, which were visited by National Geographic explorers in 2009, were as remote as they were stunning.

Mass Coral Die Off

When a record-warming event called El Nio in 2015 caused mass coral die-offs, the team of the Pristine Seas Expedition said they had been crushed. They had re-painted the picture of what a healthy coral reef should look like-teeming with life and color.

When they returned in 2021, they found an amazing sight: vibrant, healthy corals that extended as far as 100 feet off the island's slopes and were teeming with life. A team member calculated that the average number of coral colonies per square mile was between 43 million and 53 million after a record number of coral deaths.

Enric Sala, a marine biologist, explained that it took longer to get to the Southern Line Islands by plane and boat than it did for the astronauts of the Apollo missions to touch down on the Moon. The Southern Line Islands are part of the Pacific island nation of Kiribati, National Geographic reports.

Large tracts of cauliflower corals, pocillopora, and the species acropora were all gone during the trip to Vostock, Flint, and Millennium islands in 2017. However, some other species suffered less harm, giving Sala-who was busy at the time and was unable to join the 2017 expedition-hope that they could recover. Sala is also a member of the Pristine Seas Expedition.

All in the Algae

The expedition discovered encouraging evidence that the reef might be able to do just that, as the dead corals were covered in "crustose coralline algae," a marine plant that coral larvae can attach to create new reefs similar to how a brick attaches to mortar.

Indeed, the reefs surrounding the Southern Line Islands have almost completely recovered thanks to this foundation.

Sala described the reef as a "garden of Montipora aequituberculata" that stretched as far as he could see. The reef was covered in light-blue corals that resembled enormous roses.

Sala attributes the absence of seaweed over the dead corals as opposed to the mortar-like crustose coralline algae flush to the colossal population of grazing fish, such as zebrafish, surgeonfish, parrotfish, and others, who would eat any seaweed before it could outgrow the coral.

Massive Coral Spawning Event = "Super Reef"

Nobody was paying attention to how the corals were able to regenerate so significantly because of how far away the Southern Line Islands are, but Sala has an idea. Since the majority of the montipora were of similar size, it's possible that one or two significant coral spawning events-during which the corals reproduce and cast their eggs into the water before the larvae descend on the reef-will be sufficient to replenish sizable areas of dead corals.

Because of its toughness, the crew dubbed it a "super reef."

According to Sala, the corals that were resilient to the exceptional El Niño of 2015-16 were what made the reefs resilient. The corals have adapted to heat because the Southern Line Islands are located in one of the Pacific Ocean's warmest hot spots.

SLIMPA, PIPA, Commercial Fishing

The government of Kiribati has made sure that these seas, which currently make up the Southern Line Islands Marine Protected Area and have never seen extensive commercial fishing, will never see it (SLIMPA), Good News Network reports.

The Phoenix Islands Protected Area was previously closed as a no-take zone, but UNESCO has been made aware of a statement issued by the Office of the President of Kiribati on November 15, 2018, regarding the government of Kiribati's decision to lift this restriction and implement Marine Spatial Planning (MSP) for use of marine resources within the World Heritage property in a sustainable manner. A no-take zone is a government-designated marine protected area where mining, fishing, and other extractive activities are prohibited.

Consequently, UNESCO is expressing extreme concern via its website about the news that the 2014 decision would be overturned, which could affect the Outstanding Universal Value (OUV) of the World Heritage site. This issue will be brought up at the 45th session of the World Heritage Committee by the World Heritage Center and the Advisory Bodies to the World Heritage Committee.