One million corals for Colombia, the largest ocean reef restoration in the Americas

Colombia's marine treasures often go unnoticed, as the country is better known for its mountains and the colourful villages that dot its coffee-growing region. But just beneath the waves, a vibrant underwater world of more than 1,000 square kilometres of coral reefs awaits those who dive.

However, this marine wonder is in danger. Scientists, local experts, passionate activists and islanders are sounding the alarm about the deterioration of one of the Caribbean Sea's richest ecosystems as they work together to restore it.

It's nine o'clock on a Monday morning on the island of San Martin de Pajares, located in a Marine Protected Area where coral reefs can be seen at very shallow depths and in crystal clear waters, and a leisurely 45-minute boat ride from Cartagena, the most visited city in the Colombian Caribbean.

Marine biologist Elvira Alvarado is working against the clock as resources are limited. She has eight days to plant 13,500 coral fragments and is teaching a group of young volunteers how to do it.

"We are going to start with three tables, prepare the microfragmentation machines and use dead coral pieces first to practice".

The expert explains: "We take one centimetre pieces of coral and cut them into five. Then we glue the pieces on a piece of cement in the shape of a pyramid, like a 'biscuit'. They will start to grow and then fuse together. In a year, we will have a whole colony that we can transplant to a reef to restore the ecosystem".

Through her NGO, Ecomares, the biologist and her colleagues have been studying and restoring coral reefs for decades, and now they have joined a national initiative: "A million corals for Colombia".

Launched last year by the Colombian government as part of its commitments under the UN Decade of Ecosystem Restoration, the project aims to cultivate one million coral fragments and restore 200 hectares of reefs by 2023, the largest effort of its kind in the Americas.

The areas targeted for restoration cover the country's Atlantic and Pacific marine protected regions, and mainly the UNESCO Seaflower Biosphere Reserve (EN), an oceanic archipelago with coral banks, small islands and islets that are part of atolls (ring reefs), which are rare systems in this part of the world. In fact, almost 80% of the coral reefs in the Caribbean region have been lost in recent years, ravaged by coastal development, overfishing, climate change and pollution.

The project also covers the Corales del Rosario and San Bernardo National Park - home to the largest, most diverse and most developed coral reef on Colombia's mainland Caribbean coast - a place Elvira has visited since she was a student some 40 years ago.

"I went to study with my invertebrate professor, and what a beautiful place it was. It was perfect. It had all the [living] species as they were meant to be. But in less than four years after I graduated, I witnessed the damage and deterioration of the ecosystem. I saw the near extinction of two coral species and the black urchin," she recalls sadly.

The biologist witnessed the mass extinction of the staghorn and elkhorn corals of the Caribbean Acropora family in the 1980s, due to a disease outbreak, and accelerated by hurricanes, predation, rising temperatures due to climate change and sedimentation caused by pollution, among other effects.

Acrophorids grow as branches at a relatively rapid rate, and historically formed large reef structures and provided habitat for fish and invertebrates. Today, most of these reefs have been reduced to barren debris fields, an unnatural state among Caribbean ecosystems.

Alvarado has made it his life's goal to restore the beauty he once knew, studying the reproduction of these corals, as well as other species living on Colombian reefs - which are now also more endangered due to accelerating climate change worldwide - and experimenting with ways to repopulate them.

"It's like in the forest. If we cut down trees, for every tree we cut down we should plant two. Restoration should be for all ecosystems. The Earth did not become what it is just by chance, but by natural selection. Natural selection tells us that these coral species should be here, so that's what we are doing. For every coral that dies, we have to restore and try to produce more genetically different individuals that can survive disease or bleaching events in the future," she says.

In a small boat captained by Yeison Gonzalez - an islander who has lived off the sea since he was born - our UN News team arrived, ready to take part in the first day of Elvira's coral planting "marathon", just before Oceans Day.

"The sea gives us everything, but it can also take everything if we don't take care of it. Look, that house was washed away by the tide," Yeison González tells us as we arrive at the Rosario Islands, just before docking at Oceanario, a marine life conservation and education centre within the National Park that provides space, accommodation and equipment for biologists.

Alvarado's team sets up on one of the docks under two tarpaulins. As we walk around, we see some of the animals that the Oceanarium - itself a scientific research centre - is trying to protect by educating visitors about their status, including sea turtles, sharks and the all-powerful "Mero Guasa" or Goliath Grouper fish, which is now critically endangered (listed as "critically endangered" by the International Union for Conservation of Nature).

Divers, students and other volunteers gather to listen to Alvarado's instructions. The first step is to set up what they call "beds" at the chosen restoration site, Treasure Island, a few kilometres from where we are.

"We are building steel structures that will have a mesh on top in the shape of a bed. They must be one metre above the substrate [the seabed] so that the microfragments are not suffocated by the sediment," she says, while a diver draws a sketch of what they will soon be doing at a depth of six metres.

They will set up three tables and, over the next eight days, place 900 "biscuits" containing five coral microfragments of eight different species each. The number of individuals of each species will depend on how many healthy pieces of reef the divers can find and collect.

"For example, the most dominant species right now is Orbicella, which are the corals that make columnar and pagoda-like structures. They are abundant here, so we have 15 genotypes of each of them. But the Acropora Palmata [elkhorn], which is a very rare species in the park after extinction, we only have two colonies. Of course, we would like to have many more, but we have nowhere to get them from," says the marine biologist.

Alvarado stands back as UN News boards a boat with the divers, who are armed with heavy hammers, steel bars and mesh and a huge roll of tape measures.

Their work underwater is like a choreographed dance. First, they search for a clear spot to set up the bed, making sure there are no threats in the vicinity, such as colonies of algae, which compete with the corals for resources.

Once they find the perfect spot, deep enough to be protected but shallow enough to receive the necessary sunlight, the dive team begins measuring, placing and hammering metal rods to create the structure.

When finished, their work will resemble an underwater table with dozens of micro coral pieces on top, which will eventually branch out into coral colonies.

The slow-growing species placed in these beds will take a year to a year and a half to grow large enough to be transplanted to the larger reefs, completing the restoration. Once on the reefs, 70-80% will survive and become part of a larger colony.

Muy pocas personas parecen saber que los corales no son rocas ni plantas, sino animales cuya función es vital para la supervivencia de nuestros océanos e incluso para nuestra supervivencia como seres humanos.

Los viajeros y turistas suelen disfrutar de viajes para hacer snorkel en todo el mundo, y aunque es comprensible que los peces de colores, las tortugas y otras formas de vida marina sean más "populares", no deberían pasar por alto la asombrosa y compleja belleza de los corales, las "estructuras" vivas que respiran, albergan y alimentan a la mayoría de los habitantes de las profundidades.

Los corales son pequeños animales marinos coloniales. Consisten en muchas criaturas individuales, llamadas pólipos, que viven y crecen conectadas entre sí y dependen las unas de las otras para sobrevivir.

Se alimentan de plancton –si un pólipo come, lo hace toda la colonia– y viven en perfecta simbiosis (una relación mutuamente beneficiosa) con una microalga que les proporciona sus brillantes colores.

El coral suministra a las algas –oficialmente llamadas zooxantelas– un entorno protegido y los compuestos que necesitan para la fotosíntesis y, a cambio, las algas producen el oxígeno y suministran al coral la glucosa o energía.

En momentos de estrés ambiental, como el aumento de la temperatura del agua o de la salinidad, el coral libera las algas de colores de sus tejidos, que es lo que hace que aparezcan blancas –lo que se conoce como blanqueo– y que corran el riesgo de morir.

Hay más de seis mil especies de coral en el mundo, y al menos 80 llaman a Colombia su hogar. Cada una de ellas es única y hermosa a su manera, con formas y colores sorprendentes y diversos.

En el Parque Nacional de Corales del Rosario pudimos ver de cerca algunas de estas criaturas. Unas parecían grandes cerebros amarillos flotando en el azul del océano, otras se extendían como ramos de margaritas bajo el agua, otras formaban "pirámides" anaranjadas y otras eran tan suaves que se balanceaban con las corrientes submarinas en una danza hipnótica e inspiradora.

Acercarse a los corales es un espectáculo asombroso para los amantes de la naturaleza, pero a los biólogos marinos les fascinan sus formas únicas de funcionamiento y reproducción.
Jaime Rojas, director científico del Centro de Investigación, Educación y Recreación de Oceanario (CEINER), junto con Elvira Alvarado, lleva décadas investigando los diferentes tipos de reproducción sexual y asexual de los corales. 

Very few people seem to know that corals are not rocks or plants, but animals whose function is vital to the survival of our oceans and even to our survival as human beings.

Travellers and tourists often enjoy snorkelling trips all over the world, and while it is understandable that goldfish, turtles and other marine life are more 'popular', they should not overlook the amazing and complex beauty of corals, the living 'structures' that breathe, house and feed most of the inhabitants of the deep.

Corals are small, colonial marine animals. They consist of many individual creatures, called polyps, that live and grow connected to each other and depend on each other for survival.

They feed on plankton - if one polyp eats, so does the whole colony - and live in perfect symbiosis (a mutually beneficial relationship) with a microalgae that provides them with their bright colours.

The coral provides the algae - officially called zooxanthellae - with a protected environment and the compounds they need for photosynthesis, and in return, the algae produce oxygen and supply the coral with glucose or energy.

In times of environmental stress, such as increased water temperature or salinity, the coral releases the coloured algae from its tissues, which is what causes them to appear white - known as bleaching - and risk dying.

There are more than six thousand species of coral in the world, and at least 80 call Colombia home. Each is unique and beautiful in its own way, with surprising and diverse shapes and colours.

At the Corales del Rosario National Park we got to see some of these creatures up close. Some looked like big yellow brains floating in the blue ocean, others stretched like bunches of daisies underwater, others formed orange "pyramids" and others were so soft that they swayed with the underwater currents in a hypnotic and inspiring dance.
 

The most popular technique for growing and restoring corals is the one that Elvira and her team, and their more than 32 partners across Colombia, are implementing: microfragmentation.

The process of cutting small pieces of coral to encourage their growth has been around since the 1960s, but only in 2018 did a Florida biologist accidentally discover that cutting them into even smaller fragments made them grow faster.

David Vaughan accidentally broke a staghorn coral he had been growing for three years and the fragments fell to the bottom of a tank. To his surprise, just a few weeks later the tiny pieces had grown to the original size of the broken piece.

This technique allows corals to grow 40 times faster than they would in nature, which is encouraging for reefs around the world.

At the Oceanarium, which is also a major contributor to the One Million Corals for Colombia project, visitors learn about this process in special sessions, and through a permanent underwater display of different types of nurseries.

"We apply three different cultivation techniques. We have tree coral and rope type nurseries, which are for fast growing branching species, and we have table type nurseries for microfragmentation of slow growing species", highlights Oceanario's marine biologist, Alexandra Hernández.

Diving into the water with these nurseries is like witnessing a miracle. In some ways it resembles an underwater backyard garden. They look like clotheslines, but instead of socks and T-shirts, there are little pieces of coral hanging out. Then there are the floating trees, with staghorn corals branching out like banana trees.

Then there are the tables, which have interesting shapes, like an aeroplane or a shipwreck, filled with all kinds of corals and colourful fish swimming around, making it especially beautiful.

"With our work we don't just want to restore and leave it like that, because any restoration project that doesn't involve the community is bound to disappear. We can restore corals, but if we don't teach people why they should be cared for, protected, or what this work is like, people won't value it and therefore won't take care of it," Hernández adds.

Coral reefs have survived the extinction of the dinosaurs, the ice age and other massive environmental changes, and with some help, they will survive the climate changes that have so far characterised the early 21st century.

There is much more at stake: in addition to their natural beauty and the animal and plant species that depend on them for survival, coral reefs provide humans with food security through fisheries; they protect us from floods and storms; and they generate income from the millions of tourists and divers who travel to see them. Some have anti-inflammatory properties, while others provide the raw material for some cancer-fighting drugs.

"Life brings more life, so when you restore these places that were initially degraded, bring in living fragments and they start to grow, life comes, and with it comes fish. With the fish also comes the resurgence of economic activities of the people of the region. This is beneficial for everyone and for the environment; let's not forget that we owe 70% of the oxygen we breathe to the oceans," says Hernández.

A restoration project in Indonesia is living proof of the biologists' point. Scientists and the community of Salisi' Besar in South Sulawesi planted 12,600 coral fragments in 2019. By 2021, reef cover had increased from 1 per cent to more than 70 per cent, and marine life had increased by 300%. The site was christened "Hope Reef".

"We need the biogeochemical cycles that come from this ecosystem. We need the fish, the lobster, the [sea] barrier - what's going to happen 30 years from now when climate change raises sea levels if we don't have that barrier? A lot of things are going to happen," adds Elvira Alvarado.

For both biologists, the importance of coral reefs and their restoration must go beyond the scientific community and divers and capture the attention of the general public.
"We need all these types of ecosystems. It's not about what we marine biologists like to do, it's about why we do it: we do it because the people of the world need us. What would have happened if Jacques Cousteau hadn't talked to us? Nobody would have known what we have in our oceans. We have to talk. We have to learn," says Elvira Alvarado.

Participants in "A Million Corals for Colombia" include scientific experts such as Alvarado, Hernández and Rojas, diving schools, local communities, fishermen working as coral gardeners and even hotels.

Milena Marrugo works for Conservation International, the partner organisation that oversees the "A Million Corals" project and coordinates the work of the field officers. Milena accompanied UN News on the trip back to Cartagena.

"For many years this [restoration] work was very difficult because we worked independently. Before, the allies were the ones who made great efforts to work with few resources, and now that we work together for a single purpose, the efforts are greater, which makes it possible for us to achieve our goal," she says, adding that it is really important that the government, which is making a large financial investment in the project, has started to become aware of the importance of ocean restoration.

Marrugo also explains what it has been like to carry out the project in different areas of Colombia. "There are some areas where there is a lot of current, so certain types of nurseries are not viable. We have had to vary and experiment with different types: we now have rope, table, star, spider, we have vertical and horizontal nurseries and other variations. For example, in the Pacific we realised that rope nurseries were going to be a problem for migrating humpback whales".

According to the expert, the nurseries are being built, for the most part, with environmentally friendly or recycled materials that can be reused to continue this work in the future, since, as she says, this project cannot end after reaching one million coral fragments.

"We want to take our corals, which are already in the nursery phase, to their natural environment so that they can fulfil the fundamental role of really restoring the reef, achieving these 200 hectares restored. This is one more step we are working towards," she adds. She stresses that the nurseries also need constant maintenance and cleaning, which takes time and funds.
It should not be forgotten that, although Colombia has always been seen as a "green country", with its mountains and rich terrestrial ecosystems and biodiversity, almost half of its territory, 48%, stretches between the Caribbean Sea and the Pacific Ocean, so it must be protected.