Last week we discussed additives, biodegradable plastics, and bioplastics. This week we move out into the water and discuss ghost fishing, microplastics and the oceans swirling garbage patches.
Ghost Nets/Fishing/Gear
Fishing gear—much of it made of plastic—that has been abandoned, discarded, or lost at sea is referred to as ghost gear. These often massive clumps of nets, lines, traps, buoys, and other materials become entangled and often intrap sealife including turtles, whales, sharks, dolphins, seals, fish, and seabirds eventually relegating them to the past tense after they meet a rather grim demise. Those lucky enough to escape the grip of these floating tombs are often scarred for life as a result of line cutting into them.
When these ghost nets are not found bobbing in the blue abyss of the open ocean they can be found smothering coral, destroying fragile reef ecosystems. A staggering 640,000 tons of gear is left in our oceans each year. without anyone profiting from the catches, they are affecting already depleted commercial fish stocks. Caught fish die and in turn attract scavengers which will get caught in that same net, thus creating a vicious circle.
Ghost fishing is one of the greatest killers in our oceans, and not only because of their numbers. Literally, hundreds of kilometers of nets and lines get lost every year and due to the nature of the materials used to produce, predominantly plastic-based polymers, these types of gear can and will keep fishing for multiple decades, possibly even for several centuries.
Microplastics
Microplastics, basically just tiny pieces of plastic, many of which are unassuming and easily overlooked when out on a beach clean up, cause problems where ever and whenever they are found. And it is these less than five millimeter long fragments that are able to work their way into our food chain. Two types of microplastics exist, those being primary and secondary microplastics.
Primary microplastics include resin pellets that are melted down to manufacture plastic products—also known as nurdles—and microbeads added to products such as cosmetics, soaps, and toothpaste as abrasives. The entire Southern African coast is still littered with these lentil sized prophets of maritime doom following the spill of nearly 50 tons of nurdles on October 10th 2017. Find out more about how our coast if fairing in the wake of this environmental disaster almost seven months later here.
Secondary microplastics result from the fragmentation of larger plastic items this is commonplace in the ocean as rough sea’s out along our coasts and deep at sea can obliterate large pieces of petrochemical-based debris. Microfibers are individual plastic filaments that are woven together to make fabrics like polyester, nylon, acrylic, and so on.
Sunlight does eventually “photodegrade” the bonds in plastic polymers, reducing it to smaller and smaller pieces, but that just makes matters worse. These microfibres over time are released into the air and water and are often consumed by creatures from plankton all the way up to whales resulting in a trophic cascade of plastic through the food chain.
Ocean Garbage Patches
Thanks to the action of ocean currents, marine debris often collects within ocean gyres, forming what’s known as a garbage “patch”.Right now, a huge, swirling pile of trash in the Pacific Ocean is growing faster than expected and is now three times the size of France, covering roughly 1.6 million square kilometers in size — up to 16 times bigger than previous estimates, according to a recently published study. The majority of the material is plastic.
The term patch is a misnomer as it suggests trash so thick it resembles floating islands. In reality, the patches look more like a watered down vegetable soup, due to the fact that an overwhelming amount of the debris is comprised of microplastics. found throughout the water column, rather than just floating on the surface. It’s like a galaxy of garbage, populated by millions of smaller trash islands that may be hidden underwater or spread out over many miles.
There are five major gyres on Earth, which are large systems of rotating ocean currents created by global winds and tides: the North and South Pacific Gyres, the North and South Atlantic Gyres, and the Indian Ocean Gyre.
