Nestled in the bottom corner of the North Atlantic, circling Bermuda, you’ll find a sea with no coastline. Forming part of the High Seas, the Sargasso Sea is brimming with mystery and magic. Perhaps it’s the proximity to the famed Bermuda Triangle; perhaps it’s that few seem to have heard of the sea, despite its importance.

Or perhaps it’s what bobs on the surface of this sea. Hailed as “a golden floating rainforest”, the Sargasso Sea boasts vast rafts of the world’s only holopelagic seaweed, ‘Sargassum’. This is seaweed that floats freely in water and reproduces vegetatively, and is where the Sargasso Sea got its name.

The history books don’t look kindly on Sargassum. They describe it as “treacherous”, “ensnaring” and “immovable”, with many stories of ships steering well clear (or not) of the “herbaceous mass”.

While we might forgive 19th century seafarers this account, there’s every reason today to look at the seaweed – and the sea where it naturally occurs – with wonder. That it’s a haven for biodiversity and plays a disproportionately large role in oceanic carbon sequestration are just two of the many reasons it deserves recognition.

If you’re hooked by the mystique surrounding the Sargasso Sea, same. Luckily, there’s loads to explore. From what makes Sargassum so special, to the opportunities and threats it faces, to what we can all do to protect it (and why we should), join us as we take a curious dive beneath the Sargasso Sea and its golden canopy. 

Special Sargassum

The Sargasso Sea is the only place where a significant amount of Sargassum grows in the open ocean, providing a unique habitat, migration route and spawning ground far from land. As a result, it’s known to host no less than 10 endemic species and countless iconic marine species. 

At any one time, you might find marlins, swordfish, tuna, sharks and whales enjoying the sea. It’s also where turtles spend some of their ‘lost years’ – named this because the early years of a turtle’s life used to be a mystery to us!

Where local and international communities are concerned, Sargassum plays a significant role in recreational and commercial fishing. The seaweed provides a nursery for offspring, allowing fish populations the chance to mature and replenish. But Sargassum’s role extends far beyond the sea. Once washed up (typically on Bermuda’s beaches) the weed becomes an integral part of that ecosystem. For example, organisms live in and eat the Sargassum, which in turn provides food for birds and scavengers. The decomposed seaweed also plays a role in preventing soil erosion. According to the Sargasso Sea Commission, “In this way Sargassum has helped shape the island of Bermuda.”

“Sargassum has helped shape the island of Bermuda.”

Sargasso Sea Commission

Smelly Sargassum

While nature loves washed up Sargassum, many people do not. Rotting seaweed is smelly and unsightly, and it’s causing problems beyond Bermuda.

Over the past decade, strong currents and winds have pushed Sargassum as far as Ghana. Since 2009, rafts the size of football pitches have been turning up on its beaches and causing chaos in local communities that rely on fishing and tourism. 

Locals, scientists and opportunists are keen to turn the “burden into an economic, social and environmental asset”. Where washed up Sargassum had previously been harvested for use as fertiliser or cattle feed, people are now exploring its usefulness in medical, nutritional and industrial products. Ideas include using Sargassum as a biomass resource for renewable fuels and as an antibiotic/antifungal substance to inhibit HIV infection

The Sargasso Sea Commission is cautious of these proposals. It warns of the dangers of Sargassum harvesting; “…the growth of new and novel uses of Sargassum weed could radically increase demand and increase pressures for large-scale exploitation and harvesting…”.

“…the growth of new and novel uses of Sargassum weed could radically increase demand and increase pressures for large-scale exploitation and harvesting

Sargasso Sea Commission

With such a critical role to play in its surrounding and wider ecosystem, the commission wants the seaweed left where it is. While there’s every reason to explore the repurposing of washed up Sargassum in places like Ghana, protection from exploitation in its natural habitat is critical. 

Save the Sargassum

The Sargasso Sea is beyond the jurisdiction of any government, making it vulnerable to activities like shipping, overfishing, pollution and of course, commercial Sargassum harvesting. 

In 2010, the Government of Bermuda formed the Sargasso Sea Alliance with the aim to mobilise support to protect the sea. They have urged that “the Sargasso Sea is hugely more valuable as an intact and healthy ocean area than as one that is depleted and degraded.” Cheers to that!

“The Sargasso Sea is hugely more valuable as an intact and healthy ocean area than as one that is depleted and degraded.”

Sargasso Sea Commission

Thankfully, international policy is trending in the Sargasso Sea’s favour. In 1992, The Rio Declaration introduced a precautionary approach to environmental degradation, declaring that a lack of scientific evidence can’t be used as a reason to postpone measures that will prevent it. 

This policy has been used in most marine environmental treaties since, and in 2011 the International Tribunal for the Law of the Sea acknowledged the “trend towards making this approach part of customary international law”. 

Lauded as an “extraordinary open-ocean ecosystem” and “a strange and unique creation of the nature”, the Sargasso Sea and its Sargassum is slowly but surely gaining international recognition. How can we help? Here are a few ideas to get started: 

Be Curious!

  • One of the overarching goals of the Sargasso Sea Commission is to “promote international recognition of the unique ecological and biological nature and global significance of the Sargasso Sea.” So tell your parents, friends, neighbours, and pets about the Sargasso Sea and the critical role it plays in its ecosystem. 
  • What happens when oil spills meet massive islands of seaweed? Find out here. Or, read more about the mysteries of the sea in this fantastic article by The Bermudian
  • Drawing parallels between Sargassum and the Great Pacific Garbage Patch? Even if you live nowhere near either, you can still help. In your day to day life, try to use less plastic, which is derived from oil and often ends up littering our oceans. 
  • If you feel strongly about the protection of this sea, leverage the power of politics. For example, if you’re in the UK you can write directly to your local MP.
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