Famous for its seven brilliant colors of blue, Lake Bacalar is home to an ancient population of stromatolites that are about 3.5 billion years old.
The beauty of Lake Bacalar, according to Claudio Del Valle, goes deeper than the seven brilliant shades of blue of the Mexican lagoon, which vary from bright turquoise to deep cobalt. In fact, says the local tour guide, up to 100 meters deeper – to the limestone bottom of the lake, which is home to the oldest life on the planet.
Del Valle says the most important thing when visiting the long, narrow lake near the Belize border is to leave no trace. He spent years watching other groups of people before dawn as the sun cast early light over the lagoon until the brilliant thalassic colors were baked by the night's charm.
"Thanks to the boat, I had the chance to explore most of the lagoon... it was so unique, so magnificent, so beautiful," he said. “The clarity of the water makes this a unique blue-green look; it was cool just to be appreciated," he said, the bbc reports.
But the "Lake of Seven Colors" is under great threat, says Del Valle, which could not only permanently change the color of the lake, but also lead to the destruction of an ancient population of stromatolites, a living fossil that precedes humans, dinosaurs and plants, writes tg.
Del Valle moved to Bacalar in 2017 after the 7.1 earthquake in Puebla, which left him with post-traumatic stress. On the advice of a psychologist friend, he left home in San Cristobal de las Casas, 700 km southwest of Bacalar, in search of a quieter environment.
He was amazed by what he found, "It was heaven," he said, to see the lagoon of Bacalar for the first time. “You couldn't believe the sunrise and sunset, each one was so unique. But now I can see what's going on... it breaks my heart, it's wrong."
Lake Bacalar has been headed for an ecological disaster over the past decade, according to Dr Luisa Falcon, a microbial ecologist at the National Autonomous University of Mexico in Merida. In November 2015, Mexico's federal environmental protection agency issued a pollution alert for the lake. The problem reached its peak in June 2020, when the rich thalassic colors of Lake Bacalar turned a dull brown. He still hasn't made a full recovery.
But if nothing is done, the damage can go beyond the aesthetics of brightly colored water, warns Falcon. Bacalar is home to the world's largest freshwater microbialite pit—rock-like structures made by thousands of microbes that precipitate carbonate minerals.
"Bacalar microbes range in age from decades to more than 9,000 years," she said. But it's the microbialite's living fossil counterparts, the stromatolites, that date back to "about 3.5 billion years old," making the Bacalar population the oldest evidence of life on Earth.
Stromatolites resemble cauliflowers – large pillowy beige structures that grow up from the limestone bottom of the lake's lagoon. They look like rocks, but they are actually living things. The sediment extends itself millimeter by millimeter, with the help of photosynthetic organisms called cyanobacteria, until the structures turn into an underwater rocky growth that can be seen at the surface of the shallow water.
Cauliflower-like stromatolites exist in only a few places globally, and the Bacalar population reveals history frozen in time, such as the temperature or geochemical composition of water millions of years ago.
This happens because they actually preserve the physico-chemical conditions of the water in their very slow sedimentation process. Crucially, stromatolites also help recycle elements.
Microbes that make up a stromatolite take carbon from CO2 in the air and place it in the lake's carbonate to store it. Like trees, their aquatic counterpart, stromatolites actively improve our environment.
But the problem facing stromatolites is twofold, Falcon said. The lake is fed by a 450 km underground river that is part of the world's largest water cave and tunnel system along the Yucatan Peninsula. This is actually good for the stromatolites – the carbonate rock of the tunnels is thought to cause them to grow larger than normal, rising to the surface of the lagoon.
But these environments, where groundwater flows through fractures and cave systems interconnect bodies of water, also leave stromatolites more vulnerable to surface changes. And rainforest deforestation from the lagoon has increased "exponentially" in the past decade due to unsustainable agricultural practices, Falcon says.
This has led to an increase in sediments, pesticides and fertilizers entering the water during the rainy season. High levels of nitrogen and ammonium are being recorded in the lagoon, especially near the city. The composition of the water is changing – and algae and molluscs are multiplying at a rapid rate. So far, no research has shown that microbial communities can recover from environmental damage in the short term.
The local tourism industry has played a role in the degradation of Bacalar. "Bacalar as a tourist destination has received increased attention, but it is without the necessary urban planning, including sufficient sewage treatment and sanitation facilities," said Falcon. A study co-authored by Falcon found high amounts of Firmicutes, a bacteria found in the human gut, in the lagoon.
In addition, De Valle says a bustling tourist industry on the lake, including boats, kayaks, jetskis, anchors and even people standing on the edge of the lagoon, is seeing the surface of the broken stromatolites. When their surface is punctured, they die, just like coral reefs. "There are many guesthouses, hotels, Airbnbs, many do not take care of the stromatolites and mangroves that allow the natural resources of the lagoon to regenerate," he said.
In a way, Del Valle says, as a former tour guide, he was part of the problem. Bacalar, just south of the tourist hotspots of Quintana Roo, Cancun, Tulum and Playa del Carmen, was attracting close to 100 tourists a season in recent years. And local operators have cashed in. "We were doing advertising and publicity to make that place more famous and popular, knowing that it doesn't have the infrastructure, the plans, the project, to protect the lagoon," he said.
Local researcher and biologist Silvana Ibarra, member of the Civic and Scientific Council for the Restoration and Conservation of the Bacalar Lagoon and Aquifer System, agrees. "The increase of tourists in Bacalar is 600 percent in three years and the hosts are not prepared: they do not accept the carrying capacity of the ecosystem," she said.
But the slowdown in tourist activity in the last 12 months has given the 42 km long lake a chance to recover. "These problems started a decade ago and worsened two years ago, but the improvement during the pandemic was shown in that we again saw animals such as the river otter," Ibarra said. This slowed down tourist activity has also seen the colors of the lagoon come back to life, reports the Telegraph.
With more sustainable tourism, Lake Bacalar can continue its recovery and restore its reputation as the "Lake of Seven Colors". And there are some easy ways for travelers to do that, Ibarra said. She advises never touching, stepping on or sitting on stromatolites in the lagoon. She says visitors should enter the lagoon barefoot and never wearing sunscreen or makeup, as both can discolor the stromatolites. More broadly, she said, "stay in environmentally friendly hotels, and very, very important: reduce your waste."
"Come knowing that it is a fragile natural sanctuary that must be treated with care," she said. "It is important to protect the lagoon and especially to adapt to the territory, because otherwise, its natural beauty and services will be lost."
Meanwhile, before travel returns to pre-pandemic levels, Del Valle says it's up to local tourism operators to save the crystal lagoon, the largest in the Yucatan Peninsula. Del Valle has approached many of the operators surrounding the lagoon to make their tourism offerings more sustainable. "The locals, they own all the motorboats in the lagoon, there are hundreds of them. I have spoken to many of them several times to convince them," he said.
"I offered them for free, to train them to do rowing tours, to do sailing tours, things that don't affect the lagoon," he added.
"I hope that when the time is right, there will be a change in society, and with that the most important thing, which is nature, will start to heal," he said.
Thinking back to his first impressions of Lake Bacalar, that glorious world, at a time when he was struggling with his own trauma, Del Valle pauses. "It really started to do me good [again]," he said. In a way, he continued, the now-threatened lagoon was a catalyst for his recovery.
"It was the first time in my adult life that I had this sense of belonging to something."
Hopefully, with a little help, he added, Mexico's seven-colored lake will also recover."
Information source @BalkanWeb: Read more at: www.botasot.al
