Below the Surface: the Plastic Soup

Ever since I have moved to Italy to pursue my career as a marine biologist, my perspective and habits have been deeply changed. During my bachelor’s, I remember going back home to Slovenia for the holidays, always with something new to share with my family and friends. I would go to my uncle’s for a cup of tea and we would talk mostly about the human impact on the environment. He’d be telling me about different articles he had read concerning the problem of plastics and asking me questions, which I am hopefully going to answer at last.

Plastics are extremely versatile, strong and light-weight materials. Due to their low cost, bio-inertness and impeccable moisture barrier properties, these materials are suited for a variety of applications, mostly consumer packaging material (disposable single-use plastics) that pollute the lands and the oceans. The most common classes of plastics used for packaging are polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyvinyl chloride (PVC). Even though one third of plastic resin is converted into the consumer packaging material, fishing gear and aquaculture are two other major contributors of increased plastic debris in the oceans worldwide. With the growing demand, the plastic production has increased from 0.5 to 245 million tonnes per year since the 50’s!

So what does really happen when the plastics enter the ocean? Almost half of the plastics remain buoyant and get carried by ocean currents. Once these pieces become waterlogged or weighed down by epibiota, they start swimming within the water column, sinking progressively to the bottom. Before sinking completely, however, abrasion and photodegradation break the plastic pieces into smaller and smaller ones, creating microplastics. The last are hardly visible particles that are retained by a 67 μm sieve but pass a 500 μm sieve, thus can be found anywhere in the sea. In addition, they have an incredible ability to absorb and bioaccumulate persistent organic pollutants, such as DDT which was used as an insecticide and PCBs used as dielectric and coolant fluids, universally present in waters and on land at low concentrations. This process of bioaccumulation of POPs on microplastics amplifies the potential health risks of animals, including humans, since microlitter gets ingested generally by primary consumers and perpetuates throughout the trophic food web.

It is frightening to know that fragments of hard plastic, plastic bags, fishing gear, as well as textile fibers have been found in stomachs of more than 1000 specimens of 26 fish species caught in the Ionian Sea. Among them, the blackmouth catshark (Galeus melastomus), found on the continental slope between 150 and 1400 m depth, ingested all the debris categories. Hence, there is evidence that the plastic debris has already reached the deep sea environment, and further studies on the plastic litter under 100 m depth should be made.

Barely visible plastic fiber, found while analysing the sediment collected at Palombina Beach, Italy.
(Stereo microscope, magnification 16X)

Unfortunately, it does not end here because plastic debris has been found in stomachs of large pelagic fish of the Mediterranean. Swordfish (Xiphias gladius) and bluefin tuna (Thunnus thynnus), which are commercially exploited to the point of being endangered, especially the latter, which is drastically decreasing in numbers as reported on the IUCN Red List, have been found to contain 12.5% and 32.4% of plastic fragments, respectively; and even the prey they had ingested contained a high percentage of plastics.

Seabirds have been observed to feed their young with bids of plastics they have found on the shore and turtle deaths have been documented due to ingestion of plastic bags because they confused them with their prey – jellyfish.

Sadly enough, plastic does not only block the digestion, but also releases chemical substances that get absorbed by body tissues, disrupting firstly the endocrine system and secondly all the other systems that are controlled by it: e.g. reproductive, nervous. These chemicals are called endocrine disruptors. An example is bisphenol A (BPA), that has been substituted by other chemical compounds (such as BPS), which were later discovered to be even more disrupting!

There is a reason why the social media is bombarding us with visuals of whale sharks and whales carrying fishing nets around their fins, pulling straws and plastic spoons from the turtles’ nostrils, and severely deformed body parts. Entanglement visuals are disturbing for the eye, indeed, but they are a good tool to sensibilise, causing us to change immediately (or at least in my case).

Believe me or not, but sometimes it takes me many hours of meditation and sport activities to calm myself down. It frustrates me because this is a real and huge problem. Plastic is now so abundant that it became a new stratigraphic indicator of Anthropocene. And the Med has been proposed as the 6th accumulation zone for marine litter, as it represents a semi-closed basin, profoundly influenced by ship trafficking, overcrowded coastal areas, intense fishing activities and concentrated tourism. In the Adriatic Sea, most of the plastics collected and analysed derived from paint and paraffin wax, correlated to vessel industries and insulation and impregnation, respectively.

Moreover, if we thought that replacing single-use disposable plastics would solve the problem, we have been deeply mistaken. Biodegradable plastics, such as Mater-Bi, Biofilm and Bioflex, have been proven to be scarcely degradable on land and even to a poorer extend in the marine environment. The increased salinity and decreased temperature make the degradation process almost impossible to occur. Solutions?

Firstly, we need to observe our actions and understand the impact they have. At this point, we need to change our daily patterns, maybe starting with one thing at the time, so that within a year we improve.

Secondly, there shouldn’t be any generational difference. I hear the old ones saying: “It’s your turn now to make the living better,” and I can agree to some extent, for sure, but it cannot be a justification for keeping the standard habits. We are all in this together!

Whenever you walk on a beach and notice plastic pieces, pick them up. Beach clean-up is already a step towards improvement.

Thirdly, education in schools should be focused more on environmental activities. Children are like sponges, they absorb anything. By giving them proper formation, being completely transparent with them and showing that there are solutions, they will be mind blown and 200% into it.

Fourthly, more citizen scientists should get involved with researchers in order to collectively connect and find possible solutions to stop the production of plastic materials and the inappropriate disposal methods.

In conclusion, I would like to stress the importance of connection. Connection between us and connection with the Earth. I doubt that humans have been created to destroy the planet. On contrary, I think we have been given the chance to connect to our roots and realise that all in all, we are animals just like other earthlings.

2 responses to “Below the Surface: the Plastic Soup”

  1. Hello would you mind sharing which blog platform you’re working with? I’m looking to start my own blog in the near future but I’m having a difficult time making a decision between BlogEngine/Wordpress/B2evolution and Drupal. The reason I ask is because your design seems different then most blogs and I’m looking for something completely unique. P.S Sorry for getting off-topic but I had to ask!


    • Hi Millicent,
      we are using the WordPress blog platform and you can find this particular theme design among the free ones available in the WordPress. Of course it my seem different from the basic one because we have organised it according to our needs, but just that you know, it is available.
      Entire Ocean staff


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