By Dr. Becker
The explosion of plastic waste over the last several decades has had a devastating impact on the environment, and particularly the marine environment. Plastic is prized for its durability, which is part of what makes it such a pernicious environmental pollutant.
It’s very slow to break down and in some cases — if it’s not exposed to bacterial activity or sunlight — may not break down at all. The result is that our oceans are now teeming with plastic waste — some 360,000 pieces in each square mile.1 If this sounds like a lot, it’s because it is, but the problem is slated to get worse.
Global plastic production is currently doubling at a rate of 11 years, which means, according to a new study published in the Proceedings of the National Academy of Sciences (PNAS), “between 2015 and 2026, we will make as much plastic as has been made since production began.”2
90 Percent of Seabirds Have Plastic in Their Bodies
With all of that plastic swirling around in the oceans, animals that live in and around these areas are being hard hit. The PNAS study conducted a risk analysis of 186 seabird species, including shorebirds, sea ducks, gulls and others, to determine the risks of plastic pollution.
Using studies published between 1962 and 2012, the researchers found that nearly 60 percent of the species had ingested plastic, nearly 30 percent of which had plastic in their gut.
If those studies were conducted today, the researchers estimated that 90 percent of seabirds would have ingested plastic. Contrast this to 1960, when fewer than 5 percent of seabirds had plastic in their stomachs.3
Further, they expect the problem to increase if measures aren’t taken to reduce it, noting, “We predict that plastics ingestion is increasing in seabirds, that it will reach 99% of all species by 2050, and that effective waste management can reduce this threat.”4
The Tasman Sea region between Australia and New Zealand was deemed to be one of the riskiest areas as it has both a high concentration of seabirds and marine debris.
How Does Plastic Harm Marine Creatures?
Plastic harms wildlife via two primary mechanisms: entanglement and ingestion. The latter has been found to affect more than 600 species ranging in size from microorganisms to whales. If the plastic piece consumed is sharp, it can puncture a bird’s organs.
It’s also possible for the birds to consume so much plastic that it takes up most of the space in their gut, leaving little room for food (and altering the bird’s weight). Ingesting plastic is a concern not only because it can’t be digested but also because it can release toxic, hormone-disrupting chemicals. According to the PNAS study:5
“[Plastic] ingestion is known to have many effects, ranging from physical gut blockage to organ damage from leaching toxins.
Recent experimental studies have also demonstrated transmission and toxicological effects of plastics, or adsorbed chemicals, at environmentally relevant concentrations in higher vertebrates. The effect of plastic ingestion on seabirds in particular has been of concern.
This concern is due to the frequency with which seabirds ingest plastic and because of emerging evidence of both impacts on body condition and transmission of toxic chemicals, which could result in changes in mortality or reproduction.
Understanding the contribution of this threat is particularly pressing because half of all seabird species are in decline, a higher fraction than other comparable taxa.”
Birds May Mistake Plastics for Food
As for what types of plastic seabirds consume, it’s a mixed bag. Albatross skim their beaks across the top of the water when eating and thus consume many types of plastic pieces floating on the surface. Diving birds, such as parakeet auklets, may mistake plastic bits for food.6
Plastic bags, bottle caps, tiny plastic particles broken down by waves, disposable lighters, toothbrushes, tampon applicators and light sticks used in longline fishing are just some examples of the plastics being consumed by seabirds.
Other items, such as plastic six-pack beverage holders, may become wrapped around the necks of birds (and turtles, etc.), leading to deformity or suffocation. Sadly, seabird populations, like many birds, are on the decline; populations dropped nearly 70 percent between 1950 and 2010.7
What Other Threats do Seabirds Face?
Seabirds are threatened not only by plastic pollution but also by light pollution, oil spills and other pollution, such as pharmaceutical pollution, in waterways. Human disturbances on shore can cause seabirds to abandon their nests, and fishing practices can also cause seabird deaths.
In the latter case, simple interventions could help protect the birds. For instance, hanging neon orange streamers that hang directly over fishing longlines were shown to startle birds and prevent them from trying to steal the catch (and getting hooked in the process).
The Seabird Saver is another innovative invention created by a marine biologist. It’s mounted on a boat deck and sends out a harmless green laser and noise that scares off seabirds that may otherwise get snagged in fishing lines. You can see the Seabird Saver in action below.
Such innovations are incredibly important, as losing seabirds would have major repercussions on their surrounding ecosystems. University of British Columbia researcher Michelle Paleczny, who led the study showing 70 percent declines in seabird populations, told the Audubon Society:8
“Seabirds play an important role in the food web because they’re predators and they’re also prey, so their removal would influence the structure and function of the food web … Their guano also essentially fertilizes the nearby coastal environment and the food webs there.”