Sargassum serves as a safe haven
By Brianna Forte
Oh, how wonderful summer is, filled with lots of sun, beach trips, and … seaweed? From March to September and even beyond, brown bits of sargassum can be seen strewn along the shores of the Florida coast. While washed ashore, the seaweed may be a nuisance for beachgoers, in the water sargassum plays an important role for sea turtles and other small critters.
According to the Cape Eleuthera Institute, sargassum is a unique aquatic algae that can go its entire life without attaching to the bottom of the sea floor. Along with their little leaves, the National Oceanic and Atmospheric Association explains that sargassum has gas-filled bubbles known as pneumatocysts that help the seaweed float on the surface. This free floating sargassum congregates with the current to form the Sargasso Sea in the Atlantic Ocean. The Sea Education Association counts these patches of sargassum as key ecosystems that provide a source of food, protection, and breeding grounds for a wide range of animals such as fish, marine birds, crabs, and even sea turtles.
Currently, a lot of research is being conducted to examine the role sargassum plays in the life cycles of ocean animals. Baby sea turtles especially benefit from the sargassum, as it provides a safe home with plenty of food. In a study published by Katherine Mansfield, Jeanette Wyneken, and Jiangang Luo in 2021, it was confirmed that young green sea turtles travel toward the Sargasso Sea where they mainly reside within the seaweed at the ocean’s surface. This study explained that the warm water along the surface of the Sargasso Sea helps the cold-blooded sea turtles remain active, and the weblike seaweed structure provides protection from potential predators for the young sea turtles.
However, it’s not just green sea turtles that find safety within the sargassum. In another study published by Katherine L. Mansfield, Jeanette Wyneken, Warren P. Porter and Jiangang Luo in 2014, it was concluded that young loggerhead sea turtles also benefit greatly from sargassum ecosystems. In the sargassum, the loggerheads stay near the surface of the water, where they are able to absorb sunlight. This UV radiation and warm environment helps the little loggerheads grow and increases their food consumption.
While the Sargasso Sea is a key habitat for juvenile loggerhead and green sea turtles to grow up in, the global increase in ocean temperature is changing this ecosystem. In a study conducted by researchers at the Florida Atlantic University’s Harbor Branch Oceanographic Institute and collaborators, it was discovered that the increase in nitrogen and phosphorous in the water has led to these seaweed safe havens growing so fast that the sargassum becomes a harmful algal bloom. According to Nature, the combination of increased sea surface temperatures due to climate change and higher nutrients being added to the ocean from human pollution is responsible for increasing the nutrients necessary for the sargassum to reproduce so rapidly.
In the water, sargassum may provide an important habitat for young sea turtles seeking shelter, but on land this seaweed is starting to have detrimental effects on sea turtles. With the increase in sargassum reproduction, more and more seaweed is washed ashore by the currents and the wind. These piles of seaweed can prevent baby sea turtles from making it into the ocean. The Sargasso Sea Commission explains that the sea turtle hatchlings can get stuck in the massive seaweed clumps, and in the sargassum filled water the hatchlings may not successfully be able to navigate toward the open ocean.
On the beach, sargassum may be smelly and an inconvenience for beachgoers and baby sea turtles alike, but in the water this seaweed is an important safe haven for young sea turtles and other ocean animals. The next time you see a pile of seaweed on the beach, let it serve as a reminder that humans are responsible for the harmful increase of sargassum due to pollution. Take the time to thank the seaweed for helping our little friends that make it to the ocean, and take action to contain the harmful algal bloom of sargassum by researching how to reduce your nitrogen footprint and calling for the protection of the Sargasso Sea.
Sources:
http://www.ceibahamas.org/ocean-oases-understanding-the-ecology-of-sargassum-communities
https://oceanexplorer.noaa.gov/facts/sargassum.html
https://www.sea.edu/sea_research/sargassum_ecosystem
https://seaturtles.org/the-service-of-sargassum-what-happens-when-seaweed-is-removed-from-beaches/
https://royalsocietypublishing.org/doi/10.1098/rspb.2021.0057
https://www.pbs.org/wnet/nature/blog/sargassum-blooms-much-good-thing/
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