Massive Microplastic Contamination Detected In Seals & Deep-Sea Fishes
Plastic has infiltrated into the very depths of the ocean. 75% of the mesopelagic fish in the North Atlantic, a popular food item for the oceans primary predators, have tested positive for microplastic fibres in their system. The researchers further confirmed the presence of microplastic in the scat of grey seals and also in the Atlantic mackerel, eaten by the seals.
These shocking facts come to light as another team of scientists, have, in the United Kingdom, discovered microplastic fibres even in the excretion of seals kept in captivity. Further investigating the food chain, confirmed the presence of plastic in the Atlantic mackerel that these seals routinely feed on. Details of this study have been published in the journal – Environmental Pollution. Various studies have made it evident that the microscopic plastic presence is no longer just limited to the marine animals feeding near the water surface but also to those living in the deeper ends of the ocean
Another recent study in which scientists examined over 233 fishes caught from a remote area in the North Atlantic that is east of Canada’s Newfoundland revealed similarly shocking results. Approximately 73% of these fishes had micro-plastic contamination in their digestive tract. The sample fishes included many varieties of bristlemouth fish, Bean’s sawtoothed eel, lanternfish etc. Since the expedition was conducted many hundred miles away from any coastline, Alina Wieczorek, lead author and a National University of Ireland Galway’s PhD candidate, was surprised at the level of contamination discovered from the study. It is clear now that plastic pollution has infiltrated even the remotest areas of the ocean and is impacting pivotal ecological players such as the mesopelagic fish. The team of scientists too, conducting the study, were highly concerned at finding such amounts of micro-plastic in the mesopelagic fish.
Wieczorek was also partly surprised since the amount of micro-plastic found was much higher compared to the previous two studies which had found 11% and between 9-35% contamination respectively. These differences, according to Wieczorek, could be explained by the difference in the precision of the research method used. This research made use of an alkaline dissolution which was much more concentrated to separate the plastic particles from the guts and further a very fine mesh filter was used to catch even the smallest plastic pieces. Scientists from this latest expedition noted that these extremely small plastic particles make up almost 20% of the total sample, which could also explain the difference in contamination levels found in the different studies conducted.
Another interesting thing to note is that pretty much all of the plastic collected from the surface water as well as those from the fishes were plastic fibres. These plastic fibres come mostly from woven materials such as clothes or the fishing gear ropes. Clothes that use plastic material shed thousands of such microplastic fibres, especially when washed. For this reason, the scientists had to be extra careful not to let plastic fibres from their own clothes fall into the test sample.
A significant portion of the ocean’s biomass is the deep-sea fishes. These fishes, during the daytime, mainly reside in the mesopelagic zone at depths of up to 3000 ft, but swim up to feed in the nutrient-rich surface water. The plastic fibres collected from the surface water and the deep sea fishes had identical colour, shape and size, indicating that these fishes most likely consumed the plastic from the surface waters during their routine migration to the top where they feed during the daytime.
The problem of plastic in the mesopelagic fishes are not just limited to the fishes but have much larger repercussions. For one, these fishes are fed upon by some of the oceans top predators such as sharks, tuna, salmon etc. thus having the plastic contamination move up the food chain. Reports of larger marine animals fatally suffering plastic ingestion are becoming quite common. Recently, 29 kilos of plastic was found inside the tummy of a sperm whale that washed ashore in Spain. With all the seafood that people around the world love to consume, it is not hard to imagine how then the plastic particles make into the human system.
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Image from Surfrider foundation- http-//www.surfrider.org/jims-blog/entry/eating-from-a-food-chain-were-tainting-with-plastic
Another major threat to the ecosystem is the transfer of plastic pollution to the ocean floor, through the mesopelagic fishes that feed near the water surface during night time and later excrete on the seabed in the daytime when they swim back down. Scientists have already confirmed the presence of micro-plastic in deep-sea organisms.
Although the team that conducted this latest study, have not yet examined the harm caused to the fishes by the microplastic in their system, Wieczorek suspects the plastic contamination, apart from the poisoning through the toxic chemicals that it leaks, could impair their feeding impulse causing weight loss. And since we already know that plastic pollution moves up the food chain and into our system, its the adverse effects of human health is a matter of extreme concern.
University of Toronto’s scientist, Chelsea Rochman, had conducted similar studies in the past. In these, she too found the presence of micro-plastic in different marine animals including fishes from the South Pacific gyre and even among many types of fishes and bivalves such as oysters, mussels etc. commonly sold as food, in California and Indonesia. Chelsea also pointed out the importance of investigating, where and how precisely the micro-plastic enters the system of these marine animals.
None of this should come as a surprise, considering the amount of plastic we dump into the oceans every year. In case you don’t know the magnitude of the situation, read this – An era of plastic overkill. People around the world are the primary source of these microscopic plastic particles polluting our oceans, which eventually make it back into our biological system. It is obvious then that the change must begin with us by significantly reducing or even putting a complete stop to unnecessary plastic consumption. Start with yourself, and then help spread the awareness by sharing articles such as these. If you’ve already made specific lifestyle changes to reduce plastic consumption, let others know through your comment below so that they may get motivated to do the same.