In the depths of the world’s oceans, marine life is consuming plastic at an alarming rate. And although the impact is not as visible, even coral is succumbing to this lethal trend. In this recent study, scientists think they have found the route of its appeal – and it isn’t what you might think.
From the wildest stretches of the African desert to the deepest trenches of the remotest seas, the world is comprised of diverse, fascinating ecosystems that make up life on planet earth today. But although they are fascinating they are also fragile, and it seems as though humankind’s often-callous attitude towards nature is putting many life forms at risk.
As land is cleared and industrialization pumps pollutants into both air and sea, the diversity of our world is under threat. In fact, it’s estimated that as many as 2,000 species go extinct each year. And among the most threatened ecosystems of all are the ones that exist beneath the waves.
For coral reefs in particular, the future looks bleak. Although these underwater habitats currently occupy only a tiny fraction of the ocean, they support a staggering 25 percent of all marine life. In fact, there are thousands of different species of fish, crustacea, bacteria and more that live in reefs around the world.
However, these diverse ecosystems are dying at an alarming rate. In fact, according to a 2011 report by the World Resources Institute, as many as 75 percent of the oceans’ coral reefs are currently endangered – a figure that’s expected to rise to 100 percent by 2050.
Apparently, there are many factors that are contributing to the decline of the world’s coral reefs. Among them are overfishing, tourism, development and climate change. Additionally, natural occurrences such as hurricanes and disease all have a negative impact on these fragile ecosystems.
Sadly, scientists have recently begun to speculate that we can also add plastic to the list of things that are damaging our coral reefs beyond repair. In fact, back in 2015, a study by Australia’s James Cook University revealed some worrying trends.
During the study, researchers concluded that coral polyps – the organisms that form coral reefs – were consuming small pieces of plastic in alarming amounts. In fact, they appeared to be getting through them just as quickly as their usual food. Unfortunately, the study found that these plastics were then becoming lodged within the corals’ tissue, rather than being expelled as part of a normal digestive process.
According to JCU scientist Dr. Mia Hoogenboom, this process could prove a death sentence. Apparently, fragile corals need nutrients from food as well as sunlight in order to survive. If they continue to consume plastics, they could find themselves facing starvation.
But why would corals choose to consume such a toxic and unnatural substance? While creatures such as turtles, seagulls and fish might spot plastics and confuse them with food, corals have no eyes with which to make a similar mistake. So how is trash ending up in their stomachs?
Previously, many scientists assumed that corals were accidentally consuming plastics. But in a paper published in the Marine Pollution Bulletin in October 2017, researchers proposed an alternative reason. Apparently, humans might be producing plastics that are just too delicious for corals to resist.
In a laboratory study, researchers from North Carolina’s Duke University ran a series of tests on coral kept in seawater tanks. Alternatively, they placed particles of both plastic and sand inside the tanks. But while the corals rejected the sand, their reaction to the plastic was far more surprising.
In the study’s findings, the corals quickly consumed any plastic that landed near their mouths. And even though researchers tried many different types of trash, they found that the corals gobbled up a staggering 80 percent of it. The sand, meanwhile, was almost universally ignored.
Hoping to understand the appeal, researchers also tested the corals with plastic coated in nutritious microorganisms. However, to their surprise, the polyps preferred the unmodified version – consuming up to five times as much of the raw material.
For marine researcher Alexander Seymour, the conclusion was clear. “At least some of the hundreds of additives are acting as phagostimulant – a fancy word for compounds that are tasty,” he told the Washington Post in October 2017. “Plastics may be inherently tasty,” the paper’s co-author, marine science student Austin Allen, agreed.
Sadly, their bizarre choice of diet probably isn’t doing the corals any good. Although the study found that most of the plastic was expelled within six hours, in around eight percent of cases the pieces became lodged within the polyps for at least 24 hours.
So just how much of a risk does plastic pose to the fragile ecosystems of coral reefs? For anyone who has ever picked up litter on the beach, it is clear how widespread the problem is. In fact, it’s estimated that the plastic being dumped in our oceans equates to some eight million tons every year.
And while turtles entangled in packaging and seagulls caught in plastic bags have become worryingly common sights, it seems that society is less aware of the damage our wastefulness is causing beneath the waves. Hopefully, this study will show people just how far-reaching the problem of pollution can be.
Although plastics are only one of many problems faced by corals struggling to survive today, Seymour and Allen hope that their research will bring about change. If scientists are able to determine exactly what the polyps are drawn to, they will be able to remove it from future production.
Meanwhile, our oceans continue to degrade, with almost 50 percent of all marine life disappearing over the last 40 years. If we want to halt the decline, studies such as this one have a vital role to play. However, it’s also down to each of us as individuals to change the way we live and consume – if we want to leave a world behind for our children to enjoy.