TULUM, México – In the crystal-clear waters of Tulum’s pristine coast, an ominous threat looms, defying superstitions and challenging decision-makers. The invasion of pelagic seaweed known as Sargassum has become a hot topic of concern for the residents and tourists alike. As an experienced copywriter of “The Tulum Times,” we delve into the mysteries of this algae and explore the efforts to combat its relentless spread.
Sargassum, a brown chromista algae, has an intriguing lifecycle that sets it apart from other seaweeds. Unlike its counterparts, Sargassum spends its entire life floating just beneath the ocean’s surface, forming massive clumps in areas where ocean currents converge, creating what appear to be “floating islands.” There are two species of pelagic Sargassum, Sargassum fluitans and Sargassum natans, which find their way to the Caribbean shores.
Historically, Sargassum has been found in a region of the Atlantic Ocean near the Bermuda Triangle, known as the Sargasso Sea, with records dating back to 1492. As a natural phenomenon, some Sargassum breaks away from the Sargasso Sea, carried by ocean currents to the Caribbean and Gulf of Mexico. So, what has changed to make it a problem now?
Satellite imagery has revealed the emergence of a new Sargassum accumulation zone between the coasts of Africa and Brazil for over eight years, serving as the source of the massive influx of Sargassum washing up on Caribbean shores. Since 2014-2015, there have been unprecedented arrivals of Sargassum in Mexican Caribbean coasts. While some Sargassum can be beneficial in small quantities, the excess has become a major issue.
In the open ocean, Sargassum plays a crucial ecological role, providing shelter and sustenance for numerous marine species. However, when it accumulates in large quantities along coastlines, it starts to decompose, unleashing a chain of negative impacts. Its immediate effect is evident on tourism, as its unsightly presence discourages visitors. Yet, the consequences extend far beyond aesthetics.
The decomposition of Sargassum releases harmful gases, contributes organic matter to the ecosystem, interferes with the nesting and hatching of marine turtles, and depletes oxygen levels, leading to discolored and murky waters. The most affected organisms are photosynthetic organisms like seagrass, which have already vanished from some areas near the shore. Seagrass acts as a sanctuary and breeding ground for various species, safeguards the beaches from erosion, and contributes to water clarity. Losing seagrass means losing all these invaluable benefits.
Leaving Sargassum on the beach is not a viable option. Instead, experts propose the creation of a system to collect it at sea, either just before it reaches the shoreline or after it has already arrived. However, removal should avoid using heavy machinery that can compact the sand and contribute to beach erosion. Proper disposal is also essential, as burying it in the sand or placing it in unlined sacks can contaminate groundwater and ultimately find its way back into the ocean. Furthermore, dispelling the myth that Sargassum turns into sand is crucial, as it is entirely untrue.
Finding sustainable uses for Sargassum is an ongoing quest. It can be employed for biogas production, as a complement to fertilizers, and as organic fertilizer itself, though research advises against using it directly as fertilizer, recommending mixing it with compost instead. However, there is still a need for further investigation into its potential applications. Its occasional high concentrations of arsenic rule out its use in food production.
While it may be challenging to prevent Sargassum from reaching the Caribbean entirely, alert systems have been developed to predict its arrival with some certainty. However, more refined warning systems, down to the municipal level, are yet to be implemented. To minimize its negative impacts on tourism, human health, and ecosystems, a comprehensive management plan is essential. This involves handling Sargassum correctly from collection to processing, storage, and potential utilization.
In response to the Sargassum challenge, the region seeks to adopt non-invasive techniques that align with the specific needs of the area. One such technique involves the placement of a surface barrier just offshore. After months of experimentation on the Quintana Roo coasts, a cost-effective, environmentally friendly, and resilient model has been devised. This barrier interacts with surface and coastal currents, guiding Sargassum towards specific collection points, streamlining the cleanup efforts and sparing workers from arduous labor under the scorching sun, saltwater exposure, and the stench of decomposing Sargassum.