Darwin’s Eden awash in plastics
Penguin guano from the Galápagos is helping UBC researchers track microplastic pollution from around the globe
By Geoff Gilliard
In 1835, Charles Darwin visited the Galápagos Islands as part of the round the world voyage that spawned his seminal On the Origin of Species. The book made the islands famous for their unique species and biological diversity, which arose as creatures arrived and then evolved in isolation. Over millions of years those that drifted, swam or flew to the islands from continental South America diverged genetically from their mainland ancestors and became endemic to the islands: Galápagos sea lions and fur seals, Galápagos marine iguana, Galápagos giant tortoises, flightless cormorant, Darwin’s finches, and Galápagos penguins.
“Galápagos is probably the last Eden,” says Dr. Juan José Alava, a marine ecotoxicology and conservation biologist at the University of British Columbia. “We believe it’s the last oasis for us to conserve biodiversity for future generations because it’s a unique genetic bank that tells us the history of evolution.”
Ironically, the forces of nature that created the conditions for the Galápagos’ amazing biodiversity now threaten that very biodiversity. Four main ocean currents flow through the island chain’s waters from both hemispheres, carrying nutrients that help sustain zooplankton that form the basis of the islands’ vibrant marine food web. But those currents also carry oceanic plastic debris from Asia and the Americas, from fishing lines and nets, containers, bags, bottles, clothing and countless other products — even facemasks used and discarded locally during the COVID-19 pandemic.
“Climate change, overfishing and pollution are conspiring against the evolutionary processes and the composition and structure of food webs,” Dr. Alava says. “When you combine the three you amplify the impact.”
Each year an estimated eight million tonnes of plastic end up in the oceans, often breaking down into microplastics — particles or fibres less than five millimetres in size. Microplastics in water samples from the Galápagos are commonly 20 to 1,000 microns long and 10 to 20 microns thick. In comparison, a human hair is about 70 microns thick.
Many models suggest that microplastics bioaccumulate (build up in the digestive tract or other organs) at higher levels compared to the aquatic environment, or are likely to biomagnify (appear in larger and larger quantities or concentrations as they move up each trophic level in the food web).
“In the ocean, organic matter and microbial communities grow on the plastic as biofilm — known as ‘Plastiphere’ or Epiplastic communities — making it heavier and causing it to sink,” Dr. Alava says. “I think microplastics will be with us forever because they are concentrated in the sediment.”
Upwelling currents bring sediment — and the tiny plastic particles — to the surface. To zooplankton, the microplastics look similar to phytoplankton, the plant-like organisms at the base of the food web. As with larger pieces of plastic debris that are eaten by birds, fish, sea mammals and turtles, so it goes with zooplankton on a much smaller scale.
“There’s evidence that many marine animals ingest microplastics either directly through the water they filtrate or drink, or indirectly through their prey,” Dr. Alava says, who as part of UBC’s Institute for Oceans and Fisheries, and the newly formed UBC Cluster for Microplastics, Health and the Environment, has focused on how persistent organic pollutants move through ocean food webs on the west coast of South America and the northeastern Pacific. “But the main parameter that really drives the accumulation is the elimination of this particle by the organism. We need more evidence from the field.”
Karly McMullen was working as a digital marketer, travelling the globe and scuba diving whenever she had a chance. One day on a beach in Indonesia she was approached by a group of schoolchildren.
“They were drinking bags of juice and each child threw their bag on the beach when they were done,” McMullen recalls. “I pointed out the garbage can near the road and asked why they put their plastic on the beach when there was a garbage can just there. They motioned at the ocean and said ‘This is the garbage.’ I was surprised at their response, but later I realized that in Canada we have the privilege of having our garbage ‘disappear’ and are ignorant of its true destination. We throw plastic in the recycling bin and can rest easy.”
But McMullen couldn’t rest easy. She had come to love the ocean. While diving in Australia in 2017 she saw firsthand the coral bleaching caused by climate change that killed off almost one-third of the 2,300 kilometre-long Great Barrier Reef. The devastation compelled her to put her marketing and psychology training to use saving the ocean.
Back in Canada, McMullen enrolled at UBC and became a graduate student of Dr. Alava and Dr. Evgeny Pakhomov (Marine Zooplankton and Micronekton Laboratory). She’s been working to fill the knowledge gap around bioaccumulation by researching how microplastics impact animals in the Galápagos Islands. McMullen began looking for a charismatic animal that could draw public awareness to the plastic problem.
Around four million years ago currents swept penguins from the coastal shores of Perú or Chile (the Humboldt penguin, Spheniscus humboldti, is the sister species most closely related to Galápagos penguins) to the Galápagos Islands. There they evolved into the Galápagos penguin (Spheniscus mendiculus) — the world’s rarest penguin, and the only one found north of the equator. The waters from the South Pole control the islands’ climate, keeping the temperature cool enough for penguins to survive the tropical sun.
“They feed on small sea life so we can assess biomagnification, they remain in the Galápagos region year-round, and who doesn’t like penguins?” adds McMullen.
“I was curious to see how much microplastics zooplankton might be eating and how they make their way up to the penguin. If penguins aren’t eliminating the contaminant, then it’s building up more and more to the point where they’re saturated with microplastics inside. So I’m interested in penguin’s guano.”
To determine microplastic concentrations, McMullen is studying samples of seawater, zooplankton, fish stomachs and penguin guano. To gather the samples, Dr. Alava and McMullen collaborate with researchers from the Galápagos National Park and the Polytechnic School of Guayaquil in Ecuador.
In the lab, McMullen adds potassium hydroxide to the penguin guano to break down the biological material, theoretically leaving just the plastic particles. Each particle, almost invisible to the human eye, is placed in a separate Petri dish and tested to see whether it is indeed plastic. All the while, rigorous protocols are in place to make sure microplastics in the air, from clothing, or any other surface don’t contaminate the samples.
Working with UBC chemists Dr. Ed Grant and PhD candidate Matt Kowal, McMullen uses a chemical analysis technique called Raman spectroscopy to identify the polymer, or type of plastic, found in the samples. Laser light focuses on the particle under a microscope. Each particle interacts in a unique way with the laser light, producing a signal that depends on its molecular structure. The spectrum of this Raman signal serves as a fingerprint; by matching the peaks in the Raman spectrum to a library, the polymer can be identified. The technique can identify particles less than 10 microns thick.
“The big challenge is finding these tiny particles in the environment, confirming whether or not they’re plastics, and where they might have come from,” she says. “In our very early analysis we’ve found polypropene fibres, polyethylene and polyamide — commonly known as nylon — but there are still many fibres to analyze. It’s a tedious but important process to help us understand what plastics are in the samples.”
But microplastics are only part of the issue facing the Galápagos.
“Once we understand whether or not microplastics are accumulating in food webs, we can consider how climate change factors may change the rate at which microplastics are accumulated,” Dr. Alava says. “It might well be the case that climate change could exacerbate the problem.”
Climate change is making El Niño events more frequent and more intense, and the Galápagos Islands have been hit hard. El Niño events shift the cooling waters and nutrients away from the Galápagos Islands. Phytoplankton grow best in cold water, which tends to have more nutrients than warmer waters. Although Galápagos penguins have evolved somewhat to cope with the warm climate, they tend not to breed when their main source of food — sardines, anchovies and mullets — become scarce.
“The more I dig into it, the more I realize there’s so much that we don’t know,” McMullen says. “I’m really interested to see how microplastics might interact in a multi-stressor situation. Do microplastics play a role in the penguins’ survival by making it harder for their population to adapt in warming waters where there’s less food available?”
In recent years the Galápagos penguin population has declined severely, with around 1,200 of the mature seabirds in existence, placing it in the ‘Endangered’ category of the International Union for Conservation of Nature Red List.
“We need to gradually divorce from plastic if we really want to make a difference,” Dr. Alava says. “Plastic has been a benefit to society, but we need products that will biodegrade in a shorter time. Industry needs to find more environmentally friendly substitutes so we can start eliminating some of the plastic that is more harmful — like plastic bags, food packing containers and bottles that are used only once and then discarded.”
According to the UN Environmental Program, worldwide plastic production reached 348 million tonnes in 2017. Dr. Alava and McMullen hope that their research will help policy efforts to cap and control plastic waste.
The global community has banned or controlled the use of other substances that threaten life on Earth: ozone depleting chemicals, pesticides, mercury and persistent organic pollutants. The UN Environment Program has a resolution in place to forge an international agreement to tackle what it calls an epidemic of plastic pollution by 2024.
But our relationship with plastic is complicated.
“ln the Galápagos for instance, we need to be mindful of how plastics have improved people’s lives,” says McMullen. “We need to approach it in a way that’s equitable so that we’re not creating problems for people in other countries. In the global north we’ve become so accustomed to the convenience lifestyle that it will take changing our psychology and our behavior to move forward in a more sustainable way.”
The work of Dr. Alava and Karly McMullen is funded by the Nippon Foundation.
