What is the Plastisphere ?
Have you ever tripped on a discarded and worn-out Happy Meal toy while walking along the beach shore? Has it ever dawned on you that this piece of garbage can be a habitat for different microbes that have created their own community? For the past 60 years, humans have been unconsciously creating a new ecosystem in the oceans. This ecosystem is made up of different things—from toys and shoes to orange juice containers and toothpaste tubes. Labeled as the plastisphere, scientists are now concerned about this new ecosystem’s environmental impact not only to marine animals, but also to humans.
The beads absorb toxic chemicals, making them poisonous to any creature that mistakes them for food or that eats another that has ingested the plastic — all the way up the food chain.
Around the world, about 245 million tons of plastic is produced yearly. This figure represents a whopping 70 pounds of plastic thrown annually for each of the 7.1 billion people on the planet. The sad news is that of these 245 million tons of plastic per year, around 4.7 million tons of plastic garbage gathers in vast floating oval-shaped ocean garbage patches.
Although we already know that pollution destroys the ecosystem, humans have little idea of how it can also create an ecosystem of its own. These billions of tiny pieces of garbage that float in different bodies of water are exactly like an ecosystem, which humans have unwittingly made by using and throwing away too much plastic. As a result, insects and microbes that might have no business thriving in the middle of the ocean have suddenly found a new home amidst all that drifting plastic. This is now called the “plastisphere.”
A plastisphere is created when debris and garbage are washed into the ocean. This debris will be broken down into bits that are then colonized by microscopic organisms. Once trapped, the plastic particles will remain in the middle of the ocean for centuries.
Scanning electron microscope images showing examples of the rich microbial community on plastic marine debris. From Zettler, Erik Red, Tracy J. Mincer, and Linda A. Amaral-Zettler. “Life in the ‘Plastisphere’: Microbial communities on plastic marine debris.” Environmental science & technology (2013).
Like in any other ecosystem, the food web’s bottom part is often occupied by the organisms that photosynthesize, and the higher order creatures that feed on them. These creatures usually swim freely in the ocean. They need to work hard to stay near the surface to gather light that they will use for photosynthesis. By attaching themselves to a piece of floating plastic, these organisms can stay near the water surface without exerting too much effort. These food-producing bacteria will then be eaten by single-celled animals and other larger predators.
Researchers suspect that some of these small creatures sheltered in the plastisphere may be pathogens, or bacteria that cause diseases. Pathogens may travel long distances on the floating plastic scraps. In a study led by Tracy Mincer of Woods Hole Oceanographic Institution in Massachusetts and Linda Amaral-Zettler of the Marine Biological Laboratory, more than a thousand species of microbes were found during their research conducted from sites in the Northern Atlantic Ocean—including bacteria that can cause cholera and other gastrointestinal illnesses in humans.
The fear that most scientists have is that these creatures in the plastisphere are breaking down huge masses of polypropylene and polyethylene, thus allowing hazardous substances to leak into the environment. These dangerous chemicals may include harmful additives, pigments, plasticizers, flame retardants, and other toxic compounds that may leach into the water. However, scientists are not yet sure about how the zooplankton and other small organisms are responding to this.
Plastisphere and the Food Web
There has been a lot of research done to know the effects of this nearly discovered ecosystem on the food web. According to Amaral-Zettler, the purpose of the study that she conducted was to discover what dwells in the plastisphere and to find out how it functions in this ecosystem; how they are altering this ecosystem; and what the ultimate fate will be of the plastisphere dwellers in the ocean. Some experts are also speculating that some bacterial members of this new ecosystem were nestled in the so-called “pits” on the plastic debris, thus supporting the idea that these organisms play a part in the plastic’s degradation.
However, most scientists fear the effects that the plastisphere can have on the other ecosystem. The effects of plastic garbage, in general, are well documented in the news, in textbooks, and on the Internet. News about fish, birds, turtles, and other marine mammals swallowing plastic materials, suffering from clogged intestines, and choking or starving to death are rampant nowadays. Some scientists think that the hazardous chemicals showing up in ocean animals may have come from bits of plastics.
Tiny bits and pieces of plastic can be found throughout the ocean, like these collected from the open ocean by net.
For decades now, many studies have shown how plastic slowly enters the food web. In 1972, Edward Carpenter, a scientist from San Francisco State University, reported that microbes are capable of attaching themselves to pieces of plastic that float in the ocean. Growth of algae, a type of simple marine plant, is enabled by this plastic debris. Carpenter concluded that algae growth allowed bacteria to grow as well. Unfortunately, the studies made by Edward Carpenter were barely noticed for many years.
More recently, Miriam Goldstein, of UC San Diego’s Scripps Institution of Oceanography, studied plastic debris in the Great Pacific Garbage Patch between California and Hawaii. She and another oceanographer from Sea Education Association, named Deb Goodwin, released a report about the barnacles that they collected. They found out that one-third of these barnacles had plastic particles in their guts. Since crabs devour barnacles, the plastic that has been eaten by the barnacles might be spreading in the food web, which might also affect humans.
Plastisphere and Other New Studies
Further studies are needed to help people understand more about the plastisphere as a new ecosystem that might affect the food chain. Although some smaller organisms may reap the benefits offered by the plastisphere, it is clear that larger marine organisms could become endangered. This will result in the world at large becoming more conscious of this pollution.
Even Drew Talley, a marine scientist from the University of San Diego believes that more studies of the plastisphere system are essential. “It would be a crime not to investigate the damage they might be doing to the oceans and to humans,” he said. People must be aware of the extent of the effects that the plastisphere has on the environment.
Researchers are working hard to know how potentially dangerous bacteria dwell on the plastisphere, how they get there, and how they affect the surrounding ocean. New evidence was found suggesting that these “super-colonizers” can form a detectable cluster on plastics in a matter of minutes. Other findings seem to indicate that there are types of bacteria that favor plastics more than other materials. In addition, scientists have begun to explore whether fish or other marine animals help these pathogens thrive by simply ingesting plastics. This way, bacteria are then allowed to pass through the fish’s guts. The revelation of this information could help other scientists have a better understanding of the potential threat these harmful bacteria pose and the role that this new ecosystem plays in the larger ocean ecosystem, including its potential to change the nutrients contained in the water.
As the studies detailing this new ecosystem are still in their infancy, it is difficult for people to speculate about the potential effects of the emerging plastisphere on marine ecological environments. Although we are seeing bad effects of this new ecosystem among larger marine animals, scientists who are studying this new ecosystem hypothesize that the plastisphere brings new opportunity to thriving smaller organisms. Whatever the case is, further studies are still essential to better understand the life created in a barge of plastic garbage in the ocean.
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