The oceans are the world's garbage dump. It always has been and always will be, and the macro-plastic waste in the seas that we are familiar with, such as plastic bags, water bottles, single-use plastic foam containers, etc., kills marine life, from whales to sea birds to fish. When the plastic breaks down in the environment, it becomes brittle and slowly breaks down by sunlight, tumbling in the surf, and even by animals knawing on it and is known as micro-plastics.
Yale 360 notes that microplastics are a lot like a snowflake; no two are the same" they're made of many different polymers and come in a rainbow of colors. Fragments chip away as they tumble around the environment, while fibers split repeatedly. And each particle grows a unique "plastisphere" of bacteria, viruses, and algae." Like plastic, microplastics release toxic chemicals, methane (the breakdown of plastic produces greenhouse gases that will last forever) and, as already mentioned, make the world an ugly place while killing terrestrial and marine life. As a result, Humans and other animals have systemic plastic pollution in our bodies due to inhalation and ingestion of food and water.
Microplastics are making the climate even worse as researchers begin to fear that these tiny particles are “inhibiting one of the world’s most important carbon sinks, preventing planet-warming carbon molecules from being locked away in the seafloor.” The process is still in the early stages of research, but it is yet another example of the unintended consequences of our consumption of fossil fuels.
Joseph Winters writes in Grist:
To understand the potential magnitude, you first have to understand an ocean phenomenon called the “biological carbon pump.” This process — which involves a complex network of physical, chemical, and biological factors — sequesters up to 12 billion metric tons of carbon at the bottom of the ocean each year, potentially locking away one-third of humanity’s annual emissions. Without this vital system, scientists estimate that atmospheric CO2 concentrations, which recently hit a new record high of 421 parts per million, could be up to 250 parts per million higher.
snip
The pump works like this: First, carbon dioxide from the atmosphere dissolves into water at the surface of the ocean. Using photosynthesis, tiny marine algae called phytoplankton then absorb that carbon into their bodies before passing it onto small ocean critters — zooplankton — that eat them. In a final step, zooplankton excrete the carbon as part of “fecal pellets” that sink down the water column. Once these carbon-containing pellets reach the ocean floor, the carbon can be remineralized into rocks — preventing it from escaping back into the atmosphere.
snip
Perhaps most concerning to scientists is the way microplastics may be affecting that final stage, the sinking of zooplankton poop to the bottom of the seafloor. Once ingested, microplastics get incorporated into zooplankton poop and can cause fecal pellets to sink “way, way more slowly,” said Matthew Cole, a senior marine ecologist and ecotoxicologist at the Plymouth Marine Laboratory in the U.K. In a 2016 paper he published in Environmental Science & Technology, he documented a 2.25-fold reduction in the sinking rate for the fecal pellets of zooplankton that had been exposed to microplastics. Other research has shown that plastic-contaminated krill fecal pellets can sink about half as quickly as their purer counterparts.
This reduced sinking rate is a result of microplastics’ buoyancy — especially those made of low-density polymers like polyethylene, the stuff used in grocery bags and likely the most common polymer in the surface ocean. Slower sinking rates mean fecal pellets may spend up to two or even three days more than usual drifting through the water column, presenting more opportunities to be intercepted.
There are additional processes that we should address. Mainly the health of the micro-organisms. Warming oceans and ocean acidification stress phytoplankton and oxygen depletion or dead zones in some areas. These high levels of microplastics in the ocean are toxic to these organisms. Joseph Winters notes that “Cole’s experiments on copepods, a common kind of zooplankton, have shown that ingested microplastics take up space in copepods’ guts, causing them to eat less real food, produce smaller eggs that are significantly less likely to hatch, and live shorter lives”