Marine plastic pollution is present in all oceans, including remote oceanic islands. Despite the increasing number of articles on plastic pollution in the last years, there is still a lack of studies in islands, that are biodiversity hotspots when compared to the surrounding ocean, and even other recognized highly biodiverse marine environments. Articles published in the peer reviewed literature (N = 20) were analysed according to the presence of macro (>5 mm) and microplastics (<5 mm) on beaches and the marine habitats immediately adjacent to 31 islands of the Atlantic Ocean and Caribbean Sea. The first articles date from the 1980s, but most were published in the 2000s. Articles on macroplastics were predominant in this review (N = 12). Beaches were the most studied environment, possibly due to easy access. The main focus of most articles was the spatial distribution of plastics associated with variables such as position of the beach in relation to wind and currents. Very few studies have analysed plastics colonization by organisms or the identification of persistent organic pollutants (POPs). Islands of the North/South Atlantic and Caribbean Sea were influenced by different sources of macroplastics, being marine-based sources (i.e., fishing activities) predominant in the Atlantic Ocean basin. On the other hand, in the Caribbean Sea, land-based sources were more common.

Seagrass beds are increasingly impacted by human activities in coastal areas, particularly in tropical regions. The objective of this research program was to study seagrass beds characteristics under various environmental conditions in the French Antilles (FA, Caribbean Sea). A total of 61 parameters, from plant physiology to seagrass ecosystem, were tested along a gradient of anthropogenic conditions, distributed across 11 sites and 3 islands of the FA. A selection of 7 parameters was identified as relevant for the monitoring of seagrass meadows in the framework of public policies. They combined “early warning indicators” (e.g. nutrients and some trace metals) and long-term responding parameters (e.g. shoot density) adapted to management time scales. The ecological status of seagrass meadows was evaluated using a PCA. This work is a first step towards monitoring and management of seagrass meadows in the FA.

The Caribbean Sea is reported to have one of the highest levels of plastic pollution of any marine ecosystem. Much less is known about the levels of microplastics as an emerging pollutant in the marine environment, especially in the water column and benthic substrates where they can be easily ingested by marine organisms. This study was carried out to quantify marine microplastics in the Wider Caribbean using the mollusk, queen conch (Aliger gigas). We analyzed feces collected from queen conch, a non-lethal method of sampling, to investigate microplastic pollution in eleven sites across the Wider Caribbean. Microplastics were extracted by degradation of organic matter from feces with peroxide (30%) over 48 h. Microplastics were then analyzed by stereomicroscope and scanning electron microscope. Microplastics were found to be present in the feces of all 175 queen conch sampled, and in statistically different abundances among sites, but with no obvious geographical pattern. The highest and lowest levels were found in Central America; the highest being in Belize (270 ± 55 microplastics/queen conch) and Alacranes, Mexico (203 ± 29 microplastics/queen conch), whilst the lowest levels were found in Puerto Morelos, Mexico. Fibers, mostly between 1000 and 1500 μm in size, were the most frequent microplastic particle types at every site and represented between 60 and 98% of all microplastic particles found. Our results suggest that the use of queen conch feces is a suitable method for detecting benthic microplastic pollution, and have confirmed that microplastic pollution of marine benthos is widespread across the Wider Caribbean.

In recent years, the North Atlantic and the Caribbean Sea have experienced unusual and unprecedented pelagic Sargassum blooms, which may adversely affect coastal ecosystems and productive ocean. Sargassum has the potential to scavenge trace elements and radionuclides from seawater, and when bioaccumulated and thus concentrated, can pose a potential threat to higher trophic organisms, including humans that consume impacted seafood. In this study, trace elements and naturally-occurring U/Th-series radionuclides were measured in Sargassum that were collected in the coastal waters of the Caribbean Sea (Antigua/Barbuda, Belize, and Barbados) to better define baseline concentrations and activities, and to assess the scavenging potential for these trace elements and radionuclides. The mean concentration of trace elements observed in Sargassum collected across these three Caribbean Sea are ranked accordingly to the following descending order: Sr > As>Fe > Mn > Zn > Ni > V > C > Cd > Se > Co > Cr > Pb > Ag > Hg. 210-Po and ²¹⁰Pb activities in Sargassum were observed to be more elevated than previously reported values.

Marine litter is a world-wide problem, but the knowledge on this topic in remote areas such as the poles and the deep-sea is still limited. This paper seeks to provide the first accounts of deep-sea litter in the South-Western Caribbean Sea. The survey used 5066 still images from ROV video surveys around four hydrocarbon exploratory drilling zones. Forty-eight deep-sea litter items were found at depths between 427 and 2561 m, and analyzed by three different marine litter classifications. Plastic was the most frequent material (65%) and general litter the main category (69%). Almost half of the deep-sea litter items were found close to marine organism. This baseline is a first step to further research of human impact on the marine bottoms of the Caribbean. The paper highlights the importance of deep-sea litter as a descriptor of marine pollution, and the role of scientific cooperation between off-shore industry and the academy.

This baseline paper shows the Indo-Pacific mussel Perna viridis (Asian green mussel) inhabiting on floating plastic substrates in the Atlantico Department, as well as rafting on marine debris found at the Via Parque Isla de Salamanca (Magdalena). Both observations are the northernmost record of the species found in the Colombian Caribbean Sea. The above finding opens a new door that suggests that larval dispersion alone may not be the only process responsible for the presence of this invasive suspension-feeder bivalve because this species needs specific vectors for its dispersal. Some organisms such Perna viridis can persist in the marine environment, but they do not necessarily have a rafting capability that allows them to move over long distances. Floating structures as well as marine debris can serve as optimal substrates in the marine environment, contributing to an increase in the problems of non-native species on sites with a high degree of susceptibility to species invasion.

Anthropogenic beach debris was recorded during beach surveys of 24 Caribbean islands during April 2014–April 2016. Beach debris was classified according to material type (e.g., polystyrene) and item use (e.g., fishing). Geophysical features (substrate type, beach direction, and human accessibility) of sample sites were recorded in order to investigate their relationship with debris density. Results suggest the density of macro debris (items >5mm) is highest on uninhabited, sandy beaches facing a leeward direction. Higher debris quantities on inaccessible beaches may be due to less frequent beach clean ups. Frequently accessed beaches exhibited lower macro, but higher micro debris (items 1–5mm) densities, possibly due to removal of macro debris during frequent beach clean ups. This suggests that while geophysical features have some influence on anthropogenic debris densities, high debris densities are occurring on all islands within the Caribbean region regardless of substrate, beach direction, or human accessibility.

The semi enclosed Caribbean Sea is ranked as having one of the most intense maritime traffic in the world. These maritime activities have led to significant oil pollution. Simultaneously, this sea supports many critical habitats functioning as a Large Marine Ecosystem (LME). While the impacts of oil pollution are recognised, a number of management challenges remain. This study applies spatial modelling to identify critical areas potentially at risk from oil spills in the form of a potential oil spill risk (POSR) model. The model indicates that approximately 83% of the sea could be potentially impacted by oil spills due to shipping. The results from this study collectively support a management framework for minimising ship generated oil pollution in the Caribbean Sea. Among the recommended components are a common policy, surveillance and monitoring controls, standards, monitoring programmes, data collection and greater rates of convention ratifications.

Baseline data on anthropogenic seafloor debris contamination in the year 2000 is provided for 24 submersible video transects at depths of 80–900m, off the Dutch ABC-islands (Aruba, Bonaire, Curaçao), in the southeastern Caribbean Sea. In total, 202 objects were documented from a combined 21,184m of transect, ranging from sandy lower island-slope to rocky upper island-slope habitat. Debris densities differed significantly with depth. Highest debris accumulation (0.459 items 100m−2 or 4590 items per km2) occurred at depths of 300–600m on more shallow-sloping (20–30°) sand and silt bottoms. The overall average debris density was 0.27 objects per 100m2 (or 2700 items per km2), which is an order of magnitude higher than most other deepwater debris studies. What we describe may be representative for other small, populated, steep volcanic Caribbean islands. Food and beverage-related items were the single largest usage category identified (44% of objects; mostly glass beverage bottles).

Plastic resin pellets collected from remote islands in the Pacific, Atlantic, and Indian Oceans and the Caribbean Sea were analyzed for polychlorinated biphenyls (PCBs), dichloro-diphenyltrichloroethane and its degradation products (DDTs), and hexachlorocyclohexanes (HCHs). Concentrations of PCBs (sum of 13 congeners) in the pellets were 0.1–9.9ng/g-pellet. These were 1–3 orders of magnitude smaller than those observed in pellets from industrialized coastal shores. Concentrations of DDTs in the pellets were 0.8–4.1ng/g-pellet. HCH concentrations were 0.6–1.7ng/g-pellet, except for 19.3ng/g-pellet on St. Helena, where current use of lindane is likely influence. This study provides background levels of POPs (PCBs<10ng/g-pellet, DDTs<4ng/g-pellet, HCHs<2ng/g-pellet) for International Pellet Watch. Sporadic large concentrations of POPs were found in some pellet samples from remote islands and should be considered in future assessments of pollutants on plastic debris.