Could the sargassum plaguing Tobago's beaches be an opportunity?

Sargassum. Photo by Mark Yokoyama on Flickr, CC BY-NC-ND 2.0.

This article was written by Sean McCoon and originally published on Cari-Bois News. An edited version is republished here as part of a content-sharing agreement with Global Voices.

Several beaches in Tobago have once again been rendered unrecognisable by large clusters of sargassum seaweed washing ashore. The issue was recently highlighted by researchers from Trinidad and Tobago's Institute of Marine Affairs (IMA), who were in Tobago to conduct monitoring work.

The IMA advised via its social media pages that its team had “noticed a significant amount of sargassum” washing up on the shores of Little Rockly Bay, located along the island's Atlantic coast, where the impact of the brown macro-algae is most acutely felt.

As the sargassum issue has continued to evolve into a seasonal crisis for many Caribbean islands dependent on tourism, people have begun asking questions about the origin of the phenomenon: Why it is happening? Is it possible to stop it? Can sargassum seaweed be put to good use? The answers may surprise you.

What exactly is sargassum?

As the name implies, sargassum comes from the Sargasso Sea, a warm, ecologically important geographic area in the mid to northern area of the Atlantic Ocean.

Sargassum on a beach in Speyside, Tobago, on April 12, 2021. You can see bits of discarded plastic caught up in the seaweed. Photo by Sean McCoon, used with permission.

Sargassum is essentially a type of seaweed, brown algae that floats freely, offering refuge for migratory species without ever attaching to the ocean floor. While all other seas in the world are defined—at least in part—by land boundaries, the Sargasso Sea is defined only by ocean currents which, of course, give the seaweed its nomadic characteristics. Its recent proliferation is being attributed to warmer ocean temperatures as a result of the climate crisis.

Sargassum is an essential habitat for about 120 species of fish and more than 120 species of invertebrates, an important, nursery-type haven that provides shelter and food for endangered species such as sea turtles, as well as for commercially sought-after fish species like tuna.

There are two species involved in the current sargassum influx: Sargassum natans and Sargassum fluitans, which are practically ecosystems onto themselves. However, thanks to its entangled mass, sargassum also tends to accumulate marine debris like plastic, increasing the chances of fatal ingestion by fish and other organisms that live there.

The temperature of the salt water and the many nutrients it contains create ideal conditions for asexual reproduction by fragmentation. When external forces, like wind, waves, animals or boats, break up the floating mats of sargassum, the small pieces soon grow into larger ones. Given the right conditions, fragments of sargassum can span acres of the ocean’s surface.

En masse, it can give off a unique but pungent scent, a result of its constant interaction with the salt and the micro-organisms it picks up along the way. Even some of Tobago's most remote beaches, like Speyside, a popular diving locale to the north of the island, have been besieged by the “stinky” seaweed.

Landfall and its effects

This obvious presence of sargassum in coastal regions and on local beaches is bothersome—not only to Tobago, but to the Caribbean in general. Fisherfolk, tour operators, beachfront business owners, and those in tourism-reliant industries complain that this is a hindrance to their product and service offering.

The hefty amounts of sargassum that have made their way to Tobago’s shorelines have been flagged by local agencies such as the Tobago Environmental Management Authority (TEMA) as a serious risk for boat operators and others who make their living from the sea, and even for visitors who just want to enjoy the beaches.

Sargassum in the waters surrounding Tobago's capital, Scarborough, on April 14, 2021. Photo by Sean McCoon, used with permission.

Boat operators often experience difficulty in manoeuvring their vessels through the sargassum. The cleanup of such large deposits of seaweed along the shoreline is a tedious task, requiring manpower as well as specialised extraction tools and procedures.

Sargassum may be overwhelmingly perceived as a nuisance, but somewhere deep within its tendrils lie opportunities for Small Island Developing States (SIDS). With proper research, willpower and hard work, this seaweed has the potential to boost regional economies, as potentially create entirely new industries. So, what will Caribbean nations do the next time there is a sargassum invasion?

Turning a ‘plague’ into something beneficial

The solution lies in finding innovative ways to monetise sargassum, which has great potential to be used as a form of biofuel — an energy source produced through biological processes, such as agriculture and anaerobic digestion, rather than through geological processes, such as those used in the extraction of fossil fuels like coal and petroleum.

As the use of different, more sustainable types of fuel continues to be explored globally, there is room for innovative forms of renewable energy and ‘green’ ways of thinking and doing. If Caribbean governments can collaborate with individuals to invest in this opportunity post-pandemic, the region may well be on to something that can open doors for sustainable development and economic growth. Sargassum has been washing up on Caribbean beaches year after year; why not use it for all that it’s worth?

Sargassum on the beachfront in Lambeau, Tobago, on April 18, 2021. Photo by Sean McCoon, used with permission.

Opportunities for existing industries

Sargassum absorbs, stores and transports significant amounts of sea salt; it is also rich in nutrients. The concept of using sargassum as a plant fertiliser is not a new idea. Regional farmers have long trekked to coastal areas to do small-scale mining of seaweed as a natural way of enhancing their agricultural output.

Another action that is within reach for the region, is a marine or “on sea” extraction operation. The idea is to have a designated marine area, sufficiently far off the coast, to capture expanses of sargassum, prevent landfall and save on the resources needed for cleanup efforts.

The sargassum, as well as plastics and other harmful debris, can be corralled via a customised floating offshore barrier, collected by boats and repurposed or recycled in an environmentally friendly way. Once properly constructed and put into operation, sea turtles and other marine life would not be adversely affected.

Such sargassum control efforts have great advantages, not just for Caribbean economies, but also for the ability of both locals and visitors to enjoy the simple pleasures of island living.

Sean McCoon is the administration and communications representative for Environment Tobago, a non-governmental, not-for-profit organisation that focuses on environmental advocacy, education and awareness for the island.

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