Plastic pollution entering Galapagos seawater, beaches and animals
Image credit: Adam Porter
Plastic pollution has been found in seawater, on beaches and inside marine animals around the Galapagos Islands.
A new study by the University of Exeter, the Galapagos Conservation Trust (GCT) and the Galapagos Science Centre has found plastic in all marine habitats at the island of San Cristobal, where Charles Darwin first landed in Galapagos.
At the worst-polluted hotspots - including a beach used by the rare 'Godzilla' marine iguana - more than 400 plastic particles were found per square metre of beach.
Plastic was also found inside more than half of the marine invertebrates studied (such as barnacles and urchins, e.g. pictured above), as well as littering the seabed.
The findings suggest most plastic pollution in Galapagos - a world-famous biodiversity haven - arrives on ocean currents. The study also identifies the Galapagos marine vertebrates most at risk from swallowing plastic or getting entangled, including scalloped hammerheads, whale sharks, sea lions and sea turtles.
"The pristine image of Galapagos might give the impression that the islands are somehow protected from plastic pollution, but our study clearly shows that's not the case," said Dr Ceri Lewis, of Exeter's Global Systems Institute.
"The highest levels of plastic we found were on east-facing beaches, which are exposed to pollution carried across the eastern Pacific on the Humboldt Current. These east-facing beaches include Punta Pitt, a highly polluted site that is home to Godzilla marine iguanas which - like so much Galapagos wildlife - are found nowhere else in the world.
"There are less than 500 Godzilla marine iguanas in existence and it's concerning that they are living alongside this high level of plastic pollution."
Speaking about microplastic particles found inside marine invertebrates, lead author Dr Jen Jones, of GCT, said: "These animals are a crucial part of food webs that support the larger species that famously live on and around the Galapagos Islands. The potential health effects of plastic ingestion on marine animals are largely unknown and more research is needed."
The study's findings include:
- Just 2 per cent of 'macroplastic' (items and fragments larger than 5mm) was identified as coming from the islands. The true figure could be higher, but the findings strongly suggest most plastic arrives on ocean currents.
- These macroplastics were found at 13 of 14 sandy beaches studied, with 4,610 items collected in total. Large microplastics (1-5mm) sieved from the surface 50mm of sand were found at 11 of 15 sites tested.
- Significant accumulations of plastic were found in key habitats including rocky lava shores and mangroves.
- Microplastics were found in low concentrations in all seabed and seawater samples, with higher concentrations at the harbour suggesting some local input.
- All seven marine invertebrate species examined were found to contain microplastics. 52 per cent of the 123 individuals tested contained plastic.
To analyse the possible impact of plastic on Galapagos marine vertebrates such as sea lions and turtles, the researchers reviewed 138 studies of plastic ingestion and entanglement among such species worldwide.
They also considered where in Galapagos each species is known to be found and considered their conservation status on the IUCN Red List of Threatened Species. Based on this, the study identifies 27 species in need of urgent monitoring and mitigation.
Dr Jones, who led the study as part of her PhD at Exeter, said: "Our study highlights how far plastic pollution travels and how it contaminates every part of marine ecosystems. Given the level of pollution we have found in this remote location, it's clear that plastic pollution needs to stop at source. You can't fix the problem just by cleaning beaches."
Dr David Santillo, of the Greenpeace Research Laboratories at the University of Exeter, said: "This situation is only going to get worse if we don't dramatically change our use of plastics."
Last year, the research team won a £3.3m grant from the UK government to investigate and address plastic pollution in the Eastern Pacific. However, the grant has since been reduced by 64 per cent and may be cancelled altogether after the first year due to Official Development Assistance (ODA) cuts announced in March 2021.
The study was published in the journal Science of the Total Environment, titled: "Plastic contamination of a Galapagos Island (Ecuador) and the relative risks to native marine species."
In December 2020, a study showed that plastic waste is able to travel thousands of kilometres in just a few months through rivers and oceans.
This oceanic mobility was amply illustrated in April this year, when a separate study showed that a ship’s container lost overboard in the North Atlantic resulted in printer cartridges washing up everywhere from the coast of Florida to northern Norway.
The question of how so much plastic pollution ends up in the world's oceans continues to vex environmentalists, although it is now widely accepted that most of the plastic gets there from rivers. Technology is being developed and further refined to help clean up the waterways that transport the plastic pollution to the sea.
One possible natural solution was proposed earlier this year. In January, a study published in Scientific Reports suggested that the planting of underwater seagrass meadows could effectively trap, extract and carry marine plastic debris to shore, thereby helping to remove plastic litter from the sea.
Meanwhile, suitably motivated groups of people continue to take direct action against the tide of plastic waste. In April, the UK charity Surfers Against Sewage (SAS) launched its ‘Million Mile Beach Clean’ initiative, which seeks to tackle the threat of plastic pollution to marine wildlife.
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