The Caribbean is renowned globally for its stunning beaches and crystal clear ocean. However, its islands and the surrounding seas are being contaminated by plastics and other manmade fibres, posing a potential future threat to its diverse marine life and the tourism industry on which its economy depends.
That is according to a new study, the first holistic assessment of marine and land-based plastic pollution in the Southern Caribbean and some of the environmental and human factors which might influence its distribution.
The study is the result of sample analysis from a pioneering all-female Round the World sailing mission led by eXXpedition. Samples were collected in late 2019 from the seas and seafloor, and from land-based assessments.
Off the coast of five Caribbean countries, it identified 18 different polymers of plastic – including, synthetic fibres, paint flakes and acrylics – in waters across the Caribbean, with the highest concentrations (5.09 particles per m³) located off the San Blas islands in Panama.
Detailed ocean modelling and an assessment of regional policies indicated the abundance of microplastics in the area likely arose from a combination of distant sources carried by ocean currents and run-off from mainland Panama, which has some of the highest estimated levels (around 44%) of mismanaged waste in the region.
By contrast, the waters off Antigua, Bonaire and Colombia had lower quantities of terrestrial and marine plastics. Antigua, in particular, had a high diversity of polymers, with the research suggesting the majority of the microplastics collected were likely to have been transported by currents generated in the wider North Atlantic Ocean, even originating in the so-called North Atlantic garbage patch.
Writing in Science of the Total Environment, the study’s authors suggest both terrestrial litter and the microplastics identified in marine samples may arise from the maritime and tourism industries.
That in turn, they say, represents the complex challenges of managing plastic pollution since both are major contributors to the economies of the Caribbean region.
The research was led by scientists at the University of Plymouth in conjunction with the University of Georgia, Plymouth Marine Laboratory (PML) and the Technological University of Panama.
Molly James, Marine Ecosystem Modeller at PML and study participant, said: "Having followed the work of eXXpedition for a while I was excited to be asked to be involved in this project. My particular role was to use particle tracking modelling techniques to identify potential source locations of plastic fragments collected in samples taken by the eXXpedition crew. We found that ocean currents can cause transboundary movements of plastic particles within the Island groups in the Caribbean Sea which could undermine local national and national legislation aimed at reducing plastic pollution. In some cases we found that plastics found around the Caribbean Islands likely came from the wider North Atlantic Ocean. Our findings highlight the need for interdisciplinary and collaborative research and solutions to plastic pollution."
Dr Winnie Courtene-Jones, eXXpedition Science Lead and Post-Doctoral Research Fellow in the International Marine Litter Research Unit at the University of Plymouth, is the study’s lead author. She said: “Until now, evidence of the abundance of plastics within the Caribbean has been lacking. This study presents a snapshot of plastic pollution, and how it differs – in quantity, nature, origin and the policies in place to manage it – across the south of the region. It contributes towards the void of knowledge regarding marine plastic pollution in the Caribbean Sea but also highlights the need for international and interdisciplinary collaborative research and solutions to plastic pollution.”
eXXpedition’s Round the World voyage left Plymouth in October 2019 to visit some of the most important and diverse marine environments on the planet with the aim of inspiring a network of changemakers, informing effective solutions with industry and influencing policy change on land.
Emily Penn BEM, eXXpedition Founder and one of the co-authors on the current study, said: “Our vision for eXXpedition Round the World was to explore remote and inaccessible parts of the planet to pinpoint where the solutions to plastic pollution lie on land by better understanding the sources. The surprising thing from our discoveries is the huge diversity of polymer types which means the pollution has come from many different sources and as a result means the solutions need to be diverse too. We all share one planet and wherever we live the ocean connects us - this study demonstrates why for any game-changing action to tackle ocean plastic pollution all sectors of the community must come together in a holistic way across the Caribbean region and beyond.”
Professor Richard Thompson OBE, Head of the International Marine Litter Research Unit and senior author on the study, added: “It is now very clear that plastic litter presents a global environmental problem. There are changes we can all make in our everyday lives to help address that challenge. However, it is only by gaining a better understanding of how plastic debris passes from its source to the ocean that we will be fully equipped to tackle the problem.”