Feature
THE BEACH INVADER For the past decade, a prolific beach invader has wreaked seasonal havoc on idyllic beaches in the tropical Atlantic.
“ The mats of Sargassum can be massive, and when it washes to shore it can pile metres high. It can be devastating. As it decomposes, it stinks, can cause skin irritation and it gives off gases that can cause breathing difficulties.” Emma Tompkins Professor of Geography, Environment and Development
From the eastern coast of Mexico to the west coast of Africa – and everywhere in between – a potent-smelling seaweed known as Sargassum is devastating not only beaches, but livelihoods too. Moreover, climate change appears to be making it worse. Back in 2011, little was known about Sargassum. But since then, it has made its presence so prevalent that it has had researchers around the world grappling to understand where it comes from and what to do with the thousands of tonnes that wash up on shores every year. Emma Tompkins, Professor of Geography, Environment and Development, is part of a team at Southampton focusing on those questions. She also has a personal interest in understanding the seaweed conundrum, as she explained: “My family emigrated to
the Cayman Islands 35 years ago. I visited in 2018 and our favourite beach was covered in stinking seaweed, so much so that we couldn’t go into the sea. It was just bizarre.” This stinking seaweed was, Emma discovered, Sargassum. It was first spotted in extensive blooms across the tropical Atlantic in 2011. Back in Southampton, Emma worked with Robert Marsh, Professor in Oceanography and Climate, Dr Yue Zhang, Lecturer in Environmental Engineering, and researcher Dr Susan Hanson to understand more about Sargassum, finding out both climate and oceanic drivers are behind it. The basics Sargassum is a brown, large-leaf seaweed that floats. It has long been found in the Sargasso Sea, off the coast of Bermuda and, until 2011, was always contained to this area. However, an anomalous weather event in 2010 is believed to be responsible for Sargassum spreading. Seedlings were pushed south to warmer waters, where it is thriving every year. Huge rafts of Sargassum, amounting to millions of tonnes, have been spotted floating anywhere between Mexico and Ghana – some of which have measured the equivalent of 200 football pitches in size.
Workers clearing Sargassum from a Mexican beach
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Emma said: “The mats of Sargassum can be massive, and when it washes to shore it can pile metres high. It can be devastating. As it decomposes, it stinks, can cause skin irritation and it gives off gases that can cause breathing difficulties.
