Caribbean Research Paper
SOURCE, SEA AND SINK
The Caribbean is renowned globally for its stunning beaches and crystal clear ocean. However, its islands and the surrounding sea are being contaminated by plastics, posing a potential future threat to its diverse marine life and the tourism industry on which its economy depends.
To date, little work has quantified plastics within the Caribbean marine environment or examined their potential sources. We aimed to address this during eXXpedition Round the World (RTW) by conducting the first holistic assessment of marine and land-based plastic pollution in the Southern Caribbean, alongside scientists at the University of Plymouth in conjunction with the University of Georgia, Plymouth Marine Laboratory and the Technological University of Panama.
The full study – Source, Sea and Sink – a holistic approach to understanding plastic pollution in the Southern Caribbean – is published in Science of the Total Environment (November 2021)
A HOLISTIC APPROACH
In November and December 2019 our fantastic all-female crew sailed from Antigua to Panama via Bonaire, Aruba and the San Blas Islands. To study the distribution of microplastics within the Caribbean holistically, we collected samples from surface water, subsurface water and sediment to examine the abundance and distribution of microplastics in each part of the marine environment, and conducted a number of land-based surveys. Computer simulations were also used to predict where plastics collected in the samples may have come from.
Samples were collected using a manta trawl – a fine-mesh net designed to skim along the surface of the ocean – to collect microplastics floating on the surface.
We used a Niskin bottle – a container that can collect a water sample at depth – to collect samples 25 metres below the surface in order to analyse microplastics within the water column.
We conducted sediment sampling using a Van Veen grab – a metal device that collects sediment – at near-shore locations on our route to sample microplastics that have sunk to the seabed.
We conducted CAPLite Waste Management Street Surveys using the Circularity Assessment Protocol (CAP) to characterise land-based litter, logging items into the Marine Debris Tracker. The CAP has been developed by Professor Jenna Jambeck at the University of Georgia, and involved the collection of community-level data in the countries eXXpedition visited. This included mismanaged waste and waste infrastructure, and will be put into use informing decisions about how to reduce land-based plastic pollution.
We used computer simulations to give insights to where the plastics collected with the manta trawl may have originated in collaboration with Dr. Winnie Courtene-Jones, University of Plymouth, Dr. Molly James, Plymouth Marine Laboratory, Dr. Nikolai Maximenko, International Pacific Research Center and. Dr Simon van Gennip, Mercator Ocean.
5 KEY FINDINGS
Off the coast of five Caribbean countries, we identified 18 different types of plastic – including synthetic fibres, paint flakes and acrylics.
The highest concentrations of microplastics were located off the San Blas islands in Panama.
By contrast, Antigua had among the lowest quantities of terrestrial and marine plastics, yet the greatest diversity.
Tobacco products, plastic fragments and food packaging were consistently the top three categories of litter recorded in land-based surveys in every country.
Very few plastic bags or polystyrene foams were found as litter in countries which had a ban on these items (Antigua, Aruba). However polystyrene foam was identified within surface water samples.
UNDERSTANDING THE TRANSBOUNDARY MOVEMENT OF MARINE PLASTIC
We set out on eXXpedition Round the World to pinpoint where the solutions to plastic pollution lie on land by better understanding the sources.
Paint flakes identified across marine samples from the Caribbean may arise from the maritime and tourism industries, highlighting the complex challenges of managing plastic pollution since both are major contributors to the economies of the Caribbean region.
The high concentrations of microplastics located off the San Blas islands in Panama likely arose from a combination of distant sources, carried by ocean currents, and run-off from mainland Panama, which has some of the highest levels (around 44%) of mismanaged waste in the region.
The Antiguan samples had a high diversity of polymer types and computer modelling suggests these plastics may have been transported by currents generated in the wider North Atlantic Ocean, even originating from the so-called North Atlantic garbage patch.
The importance of understanding the transboundary movement of marine litter in the Caribbean, due to the prevailing ocean currents, can not be understated. Such movement can undermine local or national legislation aimed at reducing plastic pollution.
HOW TO USE THIS RESEARCH TO CREATE CHANGE
A MULTIDISCIPLINARY NEED
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. The holistic approach of this research and consequent results, highlights the importance and need for more integrated and interdisciplinary studies to better understand and inform on the most effective solutions to the multifaceted issue of plastic pollution.
Just as the types and sources of plastic pollution are many, so too must be the solutions. There’s no silver bullet solution, there’s not one thing, but there are hundreds of different ways to solve it. As well as more holistic research, what’s needed is a multidisciplinary approach to solution finding, which is the same approach we took to collecting the data for this study by involving multidisciplinary women from diverse professional backgrounds, not typically scientists, who made up the eXXpedition crew in the Caribbean.
Great thanks are extended to all the study authors, scientific partners, the vessel crew, shore team and guest crew on voyage legs 3-5 of eXXpedition Round the World. Thanks also to the Science Advisory Board and all sponsors who enabled this research, especially Travel Edge, TOMRA, SAP, Red Ensign Group, 11th Hour Racing and Slaughter and May.