By Elesha George
This story was first published on Cari-Bois Environmental News Network. A version of the article is republished below as part of a content-sharing agreement.
For decades, a sandbar off the coast of Barbuda, the smaller of the two islands that comprise the country of Antigua and Barbuda, has restrained ocean currents and protected the Codrington Lagoon from the open sea.
Formed by the very same sandbar, the lagoon is an important ecological feature that has been designated as a Wetland of International Importance under the Ramsar Convention — but the integrity of the sandbar has recently been compromised by breaches that threaten the well-being of the lagoon’s ecosystems, as well as the livelihoods of Barbudans.
How the lagoon’s defence was compromised
In 2017, a breach occurred in the sandbar after Category 5 Hurricane Irma made landfall on the island.
In the aftermath, Barbudan marine biologist John Mussington estimated that the sandbar had expanded by about 400 metres. It had not even fully recovered from the first breach when it was widened even further by the unstable weather from a trough system that moved across the northeast Caribbean in 2019.
Irma was not the first time the sandbar had been breached. Back in 1995 after the passage of Hurricane Luis, a Category 4 storm, it took less than six months to repair. This time around, researchers have observed the sandbar is taking much longer to naturally reconstruct itself.
Lagoon’s ecosystem affected
If the breach in the sandbar does not close, the area can experience several unfavourable ripple effects; the breach has already allowed predator species to enter the lagoon. President of the Barbuda Fisherfolk Association, Leroy Gore, confirmed that there has been an increase in the presence of lionfish and tiger sharks inside the lagoon.
Prior to the breach, the sharks would normally occupy the mangroves near the lagoon to breed. Now, they have been spotted throughout the entire lagoon, and Gore is fearful it poses a risk to the lives of sea bathers:
With the opening, we see a lot more activity happening within the lagoon. We see the flow of water has introduced a lot more different types of species within the lagoon. Species that were not thriving prior.
Barbuda Fisherfolk Association member Deon Desouza said that he and his peers have noticed a decline in certain fish species, including parrot fish, snapper, red hind, chub and grouper. Both Gore and Desouza agreed, however, that such a decline can also be attributed to overfishing in the area, as these species are in high demand.
Effects on species
Species like the spiny lobster, hawksbill turtle, leatherback turtle and a nesting colony of frigate birds all use the lagoon as a nursery and feeding ground.
Mussington warns that the inflow of ocean water will change the salinity level in the lagoon, which can affect the ability of some species to thrive. It can also have detrimental effects on other ecosystems, like the country’s coral reefs:
Larvae in the lagoon are taken by ocean currents throughout the region, so what happens in Barbuda impacts everywhere else. The system works because there are certain parts of it that are isolated from the ocean. With that isolation, it provides perfect sanctuary areas for juvenile fish, lobsters, conchs … all these things.
Historically, Barbudans have relied on fish as a major part of their diet. The lagoon also supports a thriving lobster fishery, so there is economic dependence as well, with some Barbudans selling their lobster catches within the community, to hotels, or exporting them to other Caribbean islands.
In some cases, fishing is the sole source of income for islanders, so any ill effects on the health and well-being of Barbuda’s fisheries can affect both food availability and livelihoods.
Increase in disaster risk
With a higher concentration of water entering the lagoon because of the compromised sandbar, it can also rush inland — especially when there is heavy rainfall and inclement weather.
In January 2020, Philmore Mullin, then director of the National Office of Disaster Services (NODS), expressed his concern about the situation, saying it increased the island's tsunami vulnerability. Barbuda’s highest point is only 125 feet (38.1 metres) above sea level, and the island is only accessible by sea and air, so in the event of a seaward disaster, the 1,500 residents of the island would be trapped.
To provide a way for people to evacuate upwards in the event of strong storm surges or widespread flooding, Mullin has suggested the construction of multi-storey buildings in Barbuda.
Climate change exacerbating the situation
In addition to rising sea levels and the effects of more intense tropical cyclones in the region, all associated with the effects of the climate crisis, Mussington claims the construction of a hotel near Codrington Lagoon contributed to an initial compromise of the sandbar.
He says the issue started in 2004 when the hotel was allowed to be built “in a manner that went against the advice of the technical experts.” He adds the issue was “made worse in 2010 when a decision was made to lease an additional 30 acres of the sandbar to the same individual. Again, technical advice was ignored.”
After construction to expand the building was completed in 2011, Mussington claims that erosion at a nearby beach was exacerbated, and a 2012 groundswell issue began to expose the foundation of the building. In an interview with Cari-Bois, Mussington emphasised that under the zoning plan for the Lagoon National Park, the area was declared a no-build zone.
How can the breach be remedied?
According to notes taken by Mussington during a workshop in Antigua in November 2019, Mullin projected that it would cost Eastern Caribbean (EC) $100 million (US $37 million) to build barriers to close the breach.
In Mussington's view, however, just as important is for the authorities to address the effects of a geotextile at Cedar Tree Point, which sits on the edge of Barbuda's world-famous bird sanctuary; tend to environmental issues at Palmetto Point, which is home to crucial ecosystems; and break down the remains of the hotel to comprehensively remedy the problem.
An artificially-induced coral reef, Mussington explained, can also be used to change the shape of the coastline. He believes a technique called electrodeposition can help regenerate coral reef systems. In this method, electric current is run through a piece of iron, which will in turn cause the deposition of calcium carbonate, which forms corals. The low-voltage charge would use solar panels to accelerate the coral’s natural formation process.
If implemented, Mussington believes that within a matter of months, these corals will start to create their own ecosystems. He has drafted a proposal in this regard and, along with a small team, is working to secure grant funding to make this pioneering solution a reality:
You will actually stimulate coral and other marine organisms to grow on that skeletal structure — and that’s exactly what a coral reef is, a skeletal structure with various organisms growing on it and soon you have an entire ecosystem.
The reefs would also allow sand to accumulate and in return, grow the size of the beach within the lagoon, with the additional benefits of stimulating seagrass and mangrove growth, and reversing the destruction of the sandbar, or at the very least, halting further erosion and creating new ecosystems.