Each season, thousands of sea turtles emerge from their nests on the beaches of Florida, in the United States, and embark on a vital journey to the sea. This journey, already complex due to the presence of predators and artificial obstacles, now faces a challenge that grows each year.
The increasingly extensive sargassum accumulations have become an unexpected barrier for the hatchlings. These mounds, which in some areas exceed 19 centimeters during the summer, interrupt the natural path of the newborns.
To understand the real impact of this phenomenon, researchers from the Florida Atlantic University evaluated how these algae alter the movement of three emblematic species that nest in the region. The tests recreated natural beach conditions to accurately measure the additional effort the hatchlings must exert.
The results showed that the presence of sargassum significantly delays the arrival to the sea, increasing the time of exposure of the turtles to environmental risks and predators.
The challenge of crossing increasingly high mounds
The experiments demonstrated that even the lowest sargassum accumulations created difficult obstacles to overcome. The hatchlings had to climb the mounds, which significantly increased the duration of the journey.
The leatherback turtles were the ones that increased their times the most when facing heavy sargassum, reaching delays exceeding 150%. The green and hawksbill turtles were not left out: both species recorded significant decreases in movement speed.
This additional effort also caused episodes of destabilization. In several cases, the hatchlings repeatedly overturned while trying to advance, further prolonging their stay on the beach.
Even so, the glucose levels recorded in the studies did not show critical decreases. This suggests that the main threat is not the immediate loss of energy, but the greater exposure to adverse conditions during a journey that should be brief.
Growing accumulations: a risk for nesting
The advance of sargassum not only hinders the journey to the sea. Its presence alters the conditions of the areas where turtles lay their eggs.
When algae accumulate in large quantities, they modify the temperature and humidity of the substrate. These changes affect the success of incubation, as the conditions of the nest are key for embryonic development.
Additionally, the dense mats can compact over time, reducing the available space for nesting. In seasons of large sargassum arrivals, several sectors of the beaches are completely or partially covered, limiting the suitable areas for reproduction.
These alterations put at risk natural cycles that depend on very specific parameters and that sea turtles have maintained for millions of years.
How sargassum affects the environment and fauna
The increase in sargassum not only impacts sea turtles. Its massive presence transforms the ecological balance of beaches and coastal areas. When the algae accumulate excessively on the shore, they begin to decompose, reducing the oxygen in the nearby water and generating gases like hydrogen sulfide, which can be toxic to various species.
The decomposition also alters the water quality, affecting juvenile fish, mollusks, and crustaceans that depend on more oxygenated and stable waters. In some areas, the fauna avoids these zones due to their unfavorable conditions.
On land, the accumulated sargassum modifies the dynamics of beach ecosystems. When compacted, it blocks access for other animals and alters the mobility of birds, crabs, and reptiles present in the environment.
These changes create a cycle of progressive degradation that affects both the resident species and those that temporarily depend on the coastal environment, such as the newly hatched turtles.
Towards coastal management adapted to the new scenario
The advance of sargassum requires faster and more coordinated management measures. Selective manual cleaning and mound management in critical areas have become essential tools.
The conservation of sea turtles requires clear routes and beaches that maintain their natural incubation conditions. The massive presence of sargassum threatens both factors.
Planning strategies to mitigate these effects is key to sustaining the protection efforts that Florida has been developing for decades. Without timely actions, the growing volume of algae could compromise the survival of the new generations of turtles that arrive each year on these shores.
