Coral reefs are no different from any other area of the earth when it comes to plastic garbage, but scientists have recently shown that the deeper the reef, the more plastic waste it is likely to contain.
Investigation of plastic pollution
Marek Okon/ via Unsplash
80 percent of all ocean garbage is made of plastic. Fish are consuming plastics at a rising pace, and marine life may get entangled in this and suffer extreme suffering, according to Lucy Woodall of the University of Exeter in the UK, as per NewScientist.
The abundance of plastic pollution at coral reefs has, however, received less attention than other oceanic areas, according to Woodall.
She claims that because many of these habitats are deep in the water, they are difficult to reach. According to Woodall, if we merely look at the surface, we will be missing a crucial element.
In the Pacific, Atlantic, and Indian oceans, Woodall and her colleagues took water samples from 84 coral reefs at 25 different locations.
These reefs range in depth from 30 to 150 meters, with some being classified shallow (less than 30 meters deep). Divers, crewed submersibles, and remote-controlled vehicles were used to gather the samples.
The researchers discovered that artificial debris measuring more than 5 centimeters across, of which 88% was plastic, had contaminated 92% of the ecosystems they had examined.
According to research, published in Nature, over three-quarters of the larger items detected on coral reefs were from ghost gear, which includes fishing equipment including ropes, lines, and nets, as per The Guardian.
Plastic bottles and food packaging were also prevalent. According to the experts, the plastic represents a new hazard to reefs that are already under stress due to the climate issue and overfishing.
Given that deeper reefs are often distant from sources of plastic pollution, the discovery that trash increased with depth was unexpected, according to Luiz Rocha, co-director of the California Academy of Sciences' Hope for Reefs program.
Reefs that were closer to crowded cities and marketplaces as well as marine protected zones, whose borders are extensively used by fishermen, had higher levels of plastic pollution.
Fishing lines and nets can affect the structure of the reefs and reduce fish diversity and richness, according to the researchers, who also observed that plastic can spread coral disease.
The worst-affected area was the Comoros island chain, which is located off the southeast coast of Africa. There were roughly 84,500 plastic objects per square kilometer there. With only 580 pieces per square kilometer, the Marshall Islands were the least contaminated.
Increased surface wave action and turbulence, which could drive trash deeper, is one possible explanation for why more plastic might be found at greater depths.
The removal of rubbish from shallower reefs by recreational divers and the growth of shallow corals, which have faster growth rates, over the waste are two other options.
The researcher emphasized that their findings show how important it is to update global agreements on tackling plastic pollution at its source and deepen marine protected areas to cover mesophotic reefs.
