Seaweeds are marine macroalgae that naturally bloom in the Atlantic Ocean. When they get washed up on beaches, they come in drove and form piles along the coastal areas. A type of seaweed known as sargassum is predicted to spread further north of the Atlantic Ocean and into Europe in the coming decades.
The Threat of an Invasion
Since 2011, an annual summer event has been conducted focusing on the influx of individual sargassum mats, which measure up to several kilometers wide. It features large piles of seaweeds that get washed up on coastal communities across the tropical Atlantic from the Caribbean to West Africa. Such massive amounts of seaweed deposits can devastate local communities, posing threats to the area's health, tourism, environment, and fishing industry.
A group of researchers from the University of Southampton assessed the growth of sargassum and its projected effect in the coming decades. They discovered that by the year 2050, the invasion would extend further north, reaching southwest Europe and making the sargassum season longer.
Sargassum is a marine organism that is very sensitive to temperature. It usually thrives in warm tropical seas but will die when the water temperature exceeds about 29 degrees Celsius. Since the oceans are predicted to be warmer by 1.5 degrees within the next 30 years, the water temperature might be too hot for the sargassum to survive in the tropical summer. This was revealed by Oceanography and Climate Professor Robert Marsh from the University of Southampton. The experts also predict that the sargassum will be more prevalent in the early part of the year and will creep towards the poles from the tropical Atlantic belt.
Additionally, they concluded that sargassum is not the carbon sink it was initially assumed to be since it has a limited capacity to absorb carbon dioxide. In the past, there has been a belief that sargassum can capture carbon from the atmosphere. However, the research team suggests that using this seaweed as a carbon sink is far from reality.
Professor Marsh further explains that sargassum is currently affecting countries that do not have the means to deal with it on their own. Because of this, he believes that international collaboration is needed to research and understand the nature of sargassum and manage it when it gets washed ashore.
What is a Sargassum?
Sargassum is a large brown macroalgae genus that includes more than 300 species. They are distributed throughout the global oceans with temperate and tropical seasons where they can grow in shallow water and coral reefs.
In the open sea, they are usually seen as leafy, rootless algae floating around the ocean. But once they get washed up on the coast, they can damage the local ecosystems, close tourism sites, and even restrict fishing yields.
Upon reaching the land, sargassum begins to rot after 48 hours, releasing irritants such as hydrogen sulfide, which is hazardous for people with respiratory issues. Aside from this, the bunch of sargassum along the coast releases a stinky smell that resembles rotten eggs or manures.
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