- Where and what is the “Great Pacific Garbage Patch”?
- Why aren’t there any satellite photos of the “Garbage Patch“?
- Where is all the plastic coming from?
- What types of plastic are causing the problem?
- How long does it take plastic to break down?
- What is the difference between photodegradation and biodegradation?
- What effect is plastic having on marine life?
- Can’t we clean up the plastic in the Gyre?
- How does this affect me? Is my health at risk?
- What are the next steps on Algalita’s research agenda?
The “Great Pacific Garbage Patch” is an area of high concentration of debris in the northeastern corner of the vortex, or center, of North Pacific Subtropical Gyre. It is also known as the “Eastern Pacific Garbage Patch” because it is theorized there is another “Garbage Patch” on the western side of the Gyre. It is not a “patch” or a floating “island” of debris, but it is actually a “plastic soup” where the plastic is distributed throughout the water column. The eastern area of the vortex is characterized by relatively consistent high pressure and little wind becoming a convergent area or accumulation zone. Algalita’s first study area in this corner of the vortex, which showed high concentrations of plastic in the surface (Manta) samples, was roughly the size of Texas. As the area of study expanded, so did the size of “Garbage Patch” to roughly twice the size of Texas.
When seen from above plastic appears as confetti on the ocean’s surface, among an occasional piece of derelict fishing gear. Many of the pieces of plastic are not seen because of the fluid dynamics of the ocean, stirring the plastic just below the surface by the wave action created by the wind and currents. Some of the floating plastic becomes fouled by plant growth or organisms attaching to it, which make it sink below the surface. Certain types of plastics are heavier than the water and sink or to the ocean floor. This cannot be captured in satellite photos.
It is estimated that land-based sources are responsible for up to 80% of marine debris. About 65% of this, or essentially half of all found in the ocean, comes from consumer-used plastics that have not been disposed of properly. These non-point (diffuse) sources include trash that comes from further inland, carelessly discarded and carried by the wind and/or down streams and rivers flowing into the sea.
Heavy storms can contribute to the immense volume of debris via flood or swift moving water. Additionally, both intentional and unintentional plastic debris “lost” in the ocean by cargo and passenger ships and the fishing industry compounds the problem.
Land-based point sources include plastic manufacturers and fabricators who inadvertently spill “nurdles” that ultimately find their way to the oceans. A “nurdle” is a pre-production plastic pellet. They are chemically produced in a few facilities and then shipped to processors where they are melted and shaped into many types of consumer products, such as toothbrushes, and nonconsumer products, such as handles for crates or packaging materials.
The majority of our samples collected in the water column at one, ten, thirty, and one hundred meter depths, contain primarily low-density polyethylene, expanded styrene (Styrofoam), polypropylene, and PET (polyethylene terephthalate). There are others, but these are the most predominant.
No one can say with certainty how long plastics will last in the environment. Depending on the type of plastic, its size and shape, its method of manufacture, the length of time to degrade can be hundreds of years or longer.
So many factors are at play, such as temperature, amount of sunlight, water chemistry, agitation, and the surface area of the material. Each situation is different. What degrades in a landfill or a municipal waste treatment plant digester does not necessarily degrade in the ocean. In any case, some of the plastic that currently exists in the ocean appears to have been there for decades. One euphemism stated by some is “That plastic, like diamonds, is forever.”
Photodegradation refers to the action of ultraviolet radiation and solar heat on plastic. In the absence of special additives (many plastics contain UV filters specifically designed to resist this natural process), the plastic weakens and breaks into pieces. This is a physical change, not a chemical one.
Biodegradation occurs when living organisms transform the chemical bonds of the plastic. In current scientific understanding, biodegradation plays a very limited role in the environmental fate of plastics. While there have been preliminary, isolated reports of specific terrestrial microorganisms that can “digest” certain types of plastic, plastic is generally NOT “digestible.”
Large pieces of plastic can kill by entrapment, suffocation and drowning. Smaller pieces can be ingested, causing choking or intestinal blockage. In some cases, starvation occurs because the plastic makes the animal feel full without having had any nourishment.
Plastic consumed by marine life appears to either pass through the digestive tract intact if it is small enough, or remains in the animal, blocking the intestinal tract, causing death.
When the animal dies, the plastic is either released to be eaten again or swallowed by a predator eating the prey. In the case of seabirds, many of them simply perish on shore. Their stomach contents are eventually all that’s left of them.
Accumulation of Persistent Organic Pollutants (POPs) on plastic, and the resulting effects on marine life when this plastic is ingested is a topic of much discussion in the scientific community. The term POP (persistent organic pollutant) is a description of organic materials that do not completely dissolve in water and do not degrade into harmless materials in a relatively short amount of time. There is a tremendous need for more research on POPs.
Examples of POPs include PCB’s (polychlorinated biphenyls) and other materials that resist degradation. Many POPs are proven carcinogens. Other POPs contribute to other problems with marine life, such as reproductive issues due to hormone disruption.
To clean the Gyre poses a whole new set of issues and obstacles; therefore, we feel the present focus should be on preventing further accumulation of polluting materials in the oceans.
Think of how difficult it would be to gather confetti from along a stretch of beach. Now imagine the area you are trying to clean is not only miles long, but also miles deep.
Plastic debris exists throughout the water column. Some of it floats, some swirls below the surface at various depths and some has already sunk to the sea floor. All the while, more and more trash is entering the area. While some of the plastic debris is large enough to be scooped out, much of it consists of tiny fragments.
Although cleaning the ocean today appears to be impractical, we embrace the creativity of those trying to solve this problem. Some of these new ideas may not only help clean up the ocean, but be applicable to the waterways entering the ocean or be appropriate to use further up the watershed.
It seems more practical to not only use some of these new ideas to help clean the ocean, but to adapt them to the waterways entering the ocean from further up the watershed, thus preventing further accumulation downstream.
There is more research needed in this area. There are questions about exactly how plastic pollution transfers pollutants associated with that plastic into the marine environment.
Not enough is known about what toxins accumulate. We are not sure how much plastic is ingested by fish, for example, and what affects the pollutants have on fish and the entire food chain.
We are fearful that toxins absorbed by fish through the ingestion of plastic is already beginning to rise within the food chain, and more research on that topic is needed.
Our team of scientists have begun analyzing water samples collected during the 2014 North Pacific Gyre Expedition. The ultimate goal is to evaluate long-term trends and changes in the Gyre by merging data collected over the past 15 years with new 2014 data.
Our land-based research includes an ongoing project examining the role of plastics in transporting POPs. Algalita biologists are currently studying fish collected during the California Bight 2013 survey to determine the type and amount of plastic ingested and analyze both the fish and plastics consumed for contaminants.