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Sargassum - A Nutrient Rich Nuisance

Sargassum Seaweed on a beach in the Virgin Islands
Image Credit: - Photographer Unknown

Sargassum is an interesting but problematic sea plant that has been plaguing the southern Atlantic states in recent years. It gets its name from the Sargasso Sea off the East Coast of the United States and the Caribbean. Cleaning it up can be a real problem and leaving it alone can lead to property damage. (Many homeowners policies won't cover fixing it either!)

Keep reading to learn what makes it unique, why you should be clearing it out and the best way to do it.

What does it look like?

Even though it’s technically an alga, Sargassum looks a lot like a seaweed. The colony is connected by a "stipe" that can grow several meters. (“Stipe” is the name of the central branch of a plant.) The "fronds" that look leaves grow from the stipe densely. The whole thing is usually kept afloat by little air bladders that look like berries. If you're a nerd about stuff like this like we are, it's actually pretty interesting.

The whole colony can be small or very large and cumbersome. It’s usually green or brown and feels slimy if you touch it. The whole colony is flexible but strong which lets it survive strong ocean currents.

Where does it grow?

In the wild, it spends most of its life floating around in the ocean. It’s native to the Sargasso Sea in the Caribbean, but due to ocean currents it finds its way all over the Gulf of Mexico too. That means in the US, it can be found in Florida, Georgia, Texas, Louisiana, Mississippi, North Carolina, South Carolina, It’s even been found as far north as Virginia, Maryland, Delaware, New Jersey and Massachusetts. It’s not found inland as often as on ocean shores.

How it’s harmful

It’s actually pretty good for the environment in really small amounts. When it dies, it falls to the ocean floor and adds nutrients to the water for other plants and sea life.

Starting in 2011 however, conditions in the waters of the Atlantic have made Sargassm plants spread a lot further than years before. This has lead to large masses washing ashore all over the Atlantic. When it decomposes it gives off a lot of sulfur gas. That means it smells like rotten eggs or a natural gas leak! Sulfur makes metal rust faster and causes breathing problems for people, especially children and the elderly.

When it dies in the sea it decomposes on the ocean floor. When it decomposes it alters the nutrient mix in the water. It’s helpful to the fish and other sea life in small quantities, but in the large masses that have been more common in recent years are a real problem. It releases sulfuric acid into the surrounding waters harming fish populations and acidifying the water. That harms the food supply of ocean mammals like Manatees.

How do you clear it out?

In the water it usually floats freely. The whole colony can be large, but thankfully it’s usually not rooted to something. The simplest strategy is to just scoop it out! Some people cut it and scoop out the pieces when it gets really big. (It’s easier to lift out of the water that way.)

On the beach, a rake and a spade are the best tools for the job. In the Caribbean it can be such a problem that backhoes are brought in to break it up and remove it. (You probably won't have to do this, we just thought it was pretty impressive.)


Every time we visit Florida, we’ve been hearing more about Sargassum from the people that visit our booth at the trade shows. Out in the wild in the past several years there have been widespread infestations of it up and down the Atlantic coast of the US, as far as Texas and Massachusetts. There are a few ways to take care of it, and you really should in order to prevent damage to your home or your boat. The Aquatic Weed Rake from Prime Waters Manufacturing is designed to be a safe and eco-friendly way to clear it from your dock, harbor or boat. Get yours today!

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