This month saw the release of the widely-anticipated second series of Netflix’s Our Planet, narrated by Sir David Attenborough.
As we were once again dazzled by the expansive cinematography of this award-winning team, and by Attenborough's signature soothing tones, the exploration of man-made climate crises was all the more jarring. In the first episode of the docuseries, we were introduced to the Laysan Albatross, a near-threatened species of which 99.7 percent of the global population nest in the Northwestern Hawaiian Islands. With beautiful panning shots of tropical waters and close-ups of albatross chicks, Attenborough soon sobered us by showing devastating scenes of the plastic-polluted shorelines on which the chicks lay. Even in these remote waters, the ocean currents mean tonnes of man-made waste is washed ashore each year. But that isn’t the full extent of the problem.
The albatross family are part of an order known as the 'tube-noses', or Procellariiformes, so named for their tubular nostrils that provide them with an exceptional sense of smell. The olfactory bulb, the part of the brain that processes scent, is also unusually large in this order. Albatross species predominantly eat cephalopods, fish, and crustaceans, which they can detect some 20 kilometres away by following scent trails containing dimethyl sulphide (DMS). DMS is a biological compound produced by phytoplankton, a marine microorganism that forms the bases of aquatic food webs and is primarily consumed by fish and crustaceans. Clouds of DMS in the open ocean form an olfactory map of which tube-noses, including albatross, may follow to find their next meal. Larger Procellariiformes, including the Laysan albatross, are also attracted to a group of chemicals called pyrazines that are emitted by krill and shrimp when they are damaged, such as when they are eaten by the fish on which albatross prey upon. So, smell is seemingly the governing sense of seabirds. How does this link to plastic pollution?
Over the past decade, researchers have discovered that plastics are ingested by marine organisms across the food chain, and that plastics acquire a 'dimethyl sulphide signature' through a process called biofouling. Biofouling is the accumulation of organisms on water-exposed surfaces, causing the plastic structure to degrade. Floating debris is known to be an excellent surface for the accumulation of DMS-producing microbiota, creating an olfactory trap for seabirds foraging the oceans. This disturbing consequence of man-made pollution was heartbreakingly depicted in Our Planet II in which we were shown albatross chicks of multiple species dead or dying on the Northwestern Hawaiian Islands. As Attenborough revealed, albatross young are being accidentally poisoned by their parents who mistake small pieces of plastic for food, which they then regurgitate for feeding. One disturbing scene showed us a Laysan albatross chick trying to regurgitate a cigarette lighter; with Attenborough lamenting that every chick on the island undoubtedly has plastic in its stomach. Once swallowed the plastic may block the birds' digestive systems, resulting in starvation and death. Some studies suggest up to 90 percent of young birds and chicks have ingested plastic, a figure that does not seem far-fetched considering the estimated eight million tonnes of plastic amassing in the sea each year.
As discussed last year at COP27 almost 75 percent of plastic becomes waste, with less than ten percent recycled worldwide. Our global demand for plastic is inextricably linked to climate change, with both plastic production and degradation creating gigantic emissions of greenhouse gases. The UN Environmental Programme estimates that global plastic pollution releases 1.7 gigatonnes of CO2 equivalent over its lifetime, with the figure set to quadruple by 2050. In the UK, climate change is increasingly leading to loss of wildlife and habitats, as well as an increase in extreme weather events. Our seabirds are at the very edge of the anthropocene, with the RSPB revealing that 24 out of 25 of our species are listed as Red or Amber status on the UK list of Birds of Conservation Concern.
