Have you noticed an increase in brown, stringy seaweed washing up on Alabama beaches? While it may not look or smell pleasant, these strandings are expected this time of year and are mostly harmless to people.

According to an article on the National Oceanic and Atmospheric Administration (NOAA) website, Sargassum is a genus of brown seaweed, which is a type of algae. It floats in "island-like masses" throughout oceans and never attaches itself to the seafloor, like you might expect seaweed to.
The site states Sargassum has "berries" attached to the leafy branches of the plant that are "gas-filled structures" mostly storing oxygen and giving the seaweed buoyancy.

The Orange Beach Coastal Resources Department confirmed this is the type of seaweed seen on the Alabama shore.

Phillip West, director of Coastal Resources, said this recurring sighting is due to the seasonally warmer temperatures leading to more algae blooms. Large blooms eventually "break off and migrate" along oceanic currents. He explained how Sargassum is typically beneficial to marine life in normal quantities.

"It provides beneficial shade and cover to a variety of species of marine life," West said on Sargassum. "However, when stranded in large quantities onshore and near to shore, it can smother some benthic (seafloor) species."

Nicole Woerner, deputy director of Coastal Resources, said this seaweed is habitat for "70 different species of marine life" as it floats along currents. The NOAA website said it provides "food, refuge and breeding grounds" for animals like fishes, sea turtles, crabs, shrimp and more. The site states that it continues benefiting marine life after it loses its buoyancy by providing energy and nutrients to "fishes and invertebrates in the deep sea."

Sargassum is also "great for composting" and often used as natural fertilizer, Woerner said. She said the plant is not something to necessarily avoid when on the beaches as it is typically safe to be near.

"The Sargassum is not inherently dangerous for people or marine life," Woerner said. "When it does break down in large quantities, the gas emitted during decomposition can cause respiratory problems for sensitive populations."

According to a previous GCM article, like other marine life, this seaweed dies when it washes ashore. The gas emitted during decomposition can cause an unpleasant smell due to hydrogen sulfide.

The GCM article focused on a large bloom that washed up along the Gulf State Park beaches in 2022 and across the shore in 2023. Sean Powers, then director of the University of South Alabama School of Marine and Environmental Sciences, said the unnaturally large bloom was caused by nutrient-rich dust storms on the coast of Africa, which are more prevalent due to deforestation by humans, he said.

While that article focused on the mass bloom heading from Africa, it later stated that Sargassum typically originates from blooms off the Texas coast. Because the route that brought the blooms in 2022 and 2023 is not regularly deposited in Alabama, scientists were not sure where it would go next.

Woerner said the City of Orange Beach uses NOAA inundation reports to track the Sargassum movement. Crews are organized by the city when "heavy strandings," like those in 2022 and 2023, are anticipated. Woerner said this year so far there has been a "lighter stranding."

"When the city does collect the Sargassum, the city utilizes tractors to drop the Sargassum off at the base of the primary dune and then add sand on top of it to help with decomposition," Woerner said on Orange Beach's response to the seaweed. "Sargassum is a natural solution for dune restoration and this method will fertilize and nourish the dune vegetation, which promotes dune growth."

Even though it seems there have been manageable amounts of seaweed on the beaches so far, curious residents and visitors can track general conditions of large blooms around Puerto Rico and in the Atlantic Ocean and Caribbean Sea on the Integrated Ocean Observing System (IOOS) website, referenced by NOAA, at www.caricoos.org/sargassum.

The website gives short-term and week-long forecasts for Sargassum concentration and abundance in the observed areas. While there is no mention of May conditions or conditions in the Gulf beyond Florida, the site does state that "continued increases" were monitored through the month of April.