Researchers assess the impact of sargassum seaweed in the TCI.

By Kristy Lee and Sylvia Myers, MSc students, University of Greenwich;
Debbie Bartlett, Ph.D., Faculty of Engineering and Science University of Greenwich;
Franziska Elmer, Ph.D. Marine Ecology Lecturer, School for Field Studies Center for Marine Resource Studies

From the UK, the Turks & Caicos Islands (TCI) are something we imagine only exists in a travel brochure, idyllic islands where sea and sky meet in one infinite colour of blue, with pure white sandy beaches. As MSc students studying Environmental Conservation at the University of Greenwich, we were interested to hear the funding bid to the Darwin Plus Initiative was successful. This UK Government grant scheme helps to protect the natural environment through locally based projects worldwide, and this specific call was focused on British Overseas Territories.

The project, in collaboration with the Department of Environment & Coastal Resources (DECR), the School for Field Studies on South Caicos and the British Overseas Territories Special Interest Group, aims to investigate the impact and potential solutions to the exceptional quantities of seaweed recently experienced on the Islands’ coastlines. It reflects the experience of the University’s algae biotechnology group in finding commercial uses for seaweeds. We were even more excited when we won the competition for two students to travel to the Islands, with our tutor, to play an active part in this project!

Our research began in the UK, finding out as much as we could about the TCI, from the history to the wildlife. We were amazed at the diversity it has to offer—coral reefs, migratory paths for whales, sea turtles and the endemic rock iguana, to name but a few. It was the field trip, however, that became central to the project, and ideas of a luxurious outing to paradise soon faded when we realised the enormity of the task. In just over two weeks we needed to find out who sargassum was affecting and see first-hand where it was being washed up, as well as study the composition of the landing, as any contamination could affect potential use. We needed to collect samples to take back to the UK for the chemists to analyse whilst also making time to absorb the culture and experience some local food!

We began our trip on Providenciales, meeting with project partners and environmental officers and visiting beaches, some completely unaffected and others affected by seaweed washing onto the shore. Seeing fish in the clear water was a novel experience and we particularly enjoyed the sea turtles, seeing at least one every day. This led us to think about whether these and other species could be affected by seaweed on the beaches and if there were any other environmental impacts that may need to be considered.

The importance of tourism to the Islands’ economy was clear and we began to understand the justification for the term “Beautiful by Nature.” We were fortunate that our short visit to Provo coincided with the famous Fish Fry, an evening festival where we experienced the warm welcome and energy of the locals, with music and dance as well as locally made products. It was a great opportunity for souvenir shopping and to learn just how many ways there are of eating conch!
Most of our stay was on South Caicos, where we were welcomed by the School for Field Studies, a residential education centre perched right on the coast and providing study programmes based on marine science. The staff introduced us to many aspects of the island, from the coral reefs and seagrass beds to the excitement of an evening of singing and dancing by local school pupils, and Saturday evenings at Triple J’s Grill. The School for Field Studies provided use of their laboratory and transported us round the island to collect samples of seaweed.

An example of a beach where no action is taken saw the most significant seaweed mass on the Islands.

We found the most common components to be Sargassum fluitans III, Sargassum natans I and Sargassum natans VIII, to give the scientific names. Sargassum has many forms (over 300!) and these particular forms are interesting as, unlike many of the others that attach to rocks and other substrates, these float on the surface of the ocean forming floating mats or rafts. This provides a rich habitat supporting many other organisms, including sea turtles, various fish and there are some species endemic to the sargassum. However, when washed ashore it can become a problem to land managers and tourism operators who have to balance respecting natural processes with keeping the beaches clean and beautiful so as not to impede the visitor experience.

Our work in the lab was to take samples and to find out which of the three forms found across the Caribbean were washing onto the beaches. The importance of this is that little is understood about the chemical characteristics of these and, if there is to be a commercial use for the seaweed, this might be affected by the mix. We developed an identification guide that is now freely available to anyone interested, and a standardised method for collecting, weighing and sorting the seaweed. This also enabled identification of any other materials, such as plastics and other inorganic matter, as well as other types of seaweed and sea grass that could affect options for more sustainable methods of disposal. Our work was carried out to the sounds of the waves beaching themselves on the rocks—exceeding our expectations of a science lab!

A quick trip to Grand Turk completed our tour of TCI, enabling us to begin to understand the diversity of these islands. Unfortunately there was simply not enough time to visit Middle or North Caicos. Grand Turk was a real contrast, with the historical buildings of Cockburn Town dating from the period when the salt industry was highly profitable. The relic salt pans were of particular interest, evidence of the island’s industrial heritage but now hosting internationally important populations of birds, many of them migratory waders, attractive to bird watchers.We enjoyed the peace and quiet and the opportunity to watch pelicans and flamingos until there was a burst of activity in response to the arrival of a large cruise ship. This is a regular occurrence with tourists visiting briefly, touring on Segways, in buggys and on horseback, with some choosing to experience the mangrove-lined creeks and nature reserves. This habitat supports both rich and diverse wildlife, whilst providing storm and flood protection for humans. Grand Turk is exposed to the easterly prevailing winds and so received more sargassum than the more westerly South Caicos and Providenciales, but we were interested to see there was no sargassum on the Cockburn Town side of the island where most of the tourism takes place.

As well as making observations, taking samples and doing our lab work, we were keen to meet as many of those involved in the tourist industry as possible to find out if the increase in seaweed on the beaches was affecting their businesses. We devised a quick questionnaire and held a focus group on the three islands visited, resulting in 100 responses from diverse operations including hoteliers, jet ski hirers, and dive and sport fishing companies. The results were very interesting, revealing that while seaweed could be a problem where it needed to be removed from beaches or could damage equipment (for example, clogging jet ski intakes), there were also some benefits—the floating rafts attract large predatory fish, benefitting sports fishing, and can stabilise beaches, preventing erosion.

This image was taken in 2018 when the estuary between McCartney Cay and Hog Cay, one of the longest mangrove channels in the country, was completely closed off with sargassum.

As always seems to be the case, initial research has generated as many questions as answers! There is no real information about how much sargassum is being deposited on the beaches and no regional information on where or when this is happening, let alone what is causing the increased amounts seen recently. To try to build up a more detailed picture, monitoring sites have been set up and there is an opportunity for anyone to get involved by sending photos with the date and location through an app called epicollect5. Simply find and download the app, select “sargassum watch” and start collecting scientific data that will feed into a Caribbean-wide monitoring. Take a picture with the app every time you go to the beach even if it is sargassum free. It’s so easy to become a citizen scientist and your help is greatly appreciated!

We were sad to leave but returned with samples of the seaweed which is now producing interesting results in the university laboratories. It is early days, but the initial results are causing some excitement among the chemists and we expect full results to be available in the near future. We feel a lot has been achieved in the first six months of this two-year project, and we are grateful to Darwin Plus for enabling us the opportunity to take part in this research and to experience the “Beautiful by Nature” Turks & Caicos Islands.

If you would like to contribute any photos to our project to help build on our sargassum map in the TCI, you can do so by emailing them to franziskaelmer@hotmail.com.