Plastics and Earth’s Ocean: Part 1
Planet Earth’s Ocean has got 5 trillion problems and it’s all plastic.
What is plastic
From the Greek πλαστικος (plastikos), the term “plastics” literally means “fit for molding”. Plastic derives from cellulose and fossil fuel-based chemicals, like natural gas or petroleum. This material is malleable during manufacture, which allows it to cast, press, and extrude in a variety of shapes. There are other properties that have been crucial for plastic use, such as lightweight, durable, flexible, and inexpensive. All these convenient features have led to extremely widespread use.
Sometimes, when we think of plastic, we might picture the hard pieces or the classic plastic bottle, but it is so much more pervasive than we think. Plastics are in houses, cars, toys, screens, IT tools, medical equipment, and more. Even our clothes can have plastics and quite a lot of them. The critical feature here is durability. Durability is the characteristic that makes plastic so unsustainable for planet Earth because its lifecycle it’s so long. Few examples of durability of different plastic types are in the table below:
|Plastic bag||20 years|
|Coffee cup||30 years|
|Plastic straw||200 years|
|6 pack plastic rings||400 years|
|Plastic water bottle||450 years|
|Coffee pod||500 years|
|Plastic cup||450 years|
|Disposable diaper||500 years|
|Plastic toothbrush||500 years|
The Great Pacific Garbage Patch
Now, imagine plastics, of any kind, being disposed of from land use into the sea. It is discarded, disappears from our sight, and ends up somewhere so far to probably not be seen again. With this in mind, we are not taking into consideration the regular eternal dynamics of the ocean currents. A so-called “gyre” in marine physics is described as “any large system of circulating ocean currents”, which forms some sort of gigantic loop in the ocean. Therefore, the plastics disposed of in different distant countries, eventually land in a Subtropical Convergence Zone, which accumulates it all in a big patch, the Great Pacific Garbage Patch (GPGP).
The GPGP sits halfway between Hawaii and California and consists of 1.6 million km^2 of plastics. That is 2 times the size of Texas and 3 times the size of France, making it the largest accumulation of plastics in the world. Of all the accumulated debris, around 50% is single-use plastics. Our unawareness and unsustainable use literally lead to the formation of a human-made island, made entirely of plastics.
Impacts on the marine environment
Over 1 million seabirds and 100,000 marine animals die from plastic pollution every year. The main hazards of plastics for marine life are ingestion, entanglement, injury, and infection. Aquatic animals can mistake plastic for food. If you think about it, pre-production pellets look like little eggs. Upon ingestion, especially in high quantities, plastic accumulation will block digestive tracts and diminish the urge to eat. This can alter feeding behavior and reduce growth and reproductive output. Eventually, some animals have their stomachs filled with plastic and will starve and die. Moreover, hundreds of marine species suffer from plastic suffocation and entanglement. This happens mainly with fishnets, but can easily also happen with plastic rings, gloves, and other materials. Animals can get entangled, and this can easily be lethal as it can prevent proper swimming, feeding, or resurfacing.
Entanglements also subject marine life to lacerations and internal injuries. Considering that every day around 8 million pieces of plastic make their way into our oceans, ingestion and entanglement risk is pretty high for the life inhabiting it. Furthermore, floating plastics can disrupt ecosystems as they contribute to the spread of invasive marine organisms and bacteria. The microbial community colonizing marine plastic debris has been identified as potentially pathogenic “hitchhikers” in the so-called Plastisphere. Certain toxic bacteria living on the surfaces of microplastics are actually capable of causing coral bleaching and triggering wound infections in humans.
These are just some of the risks that have been researched and assumed on plastics, but just as we cannot study the extent of life in the ocean, we cannot see the extent of plastics in it either. Plastic has been found as far as 11km deep, contaminating the most remote places on Earth, hence we might never know the full potential damage operated from plastic pollution on marine ecosystems.
By Costanza Manes, One Health Research Fellow