The effects of marine debris and how we are working to combat it.
Pushing away trash while peacefully floating in the ocean on a hot summer day or running your hands through soft sand only to find used plastic spoons is not how most vacationers would like to spend their beach day. What’s even more upsetting, however, is watching the environment face severe harm from a growing epidemic of marine debris. According to the Ocean Conservancy’s Trash Free Seas Alliance, an estimated eight million metric tons of debris end up in the ocean each year (6). This not only has immediate effects on ocean life, water quality, and food safety but also contributes to climate change (3). Luckily, scientists are working on harnessing specific plastic-eating bacteria as a way to dispose of plastic waste, marine debris included.
When a sea turtle, for example, sees a fish net floating towards them, they often mistake it for food and eat it, ingesting the plastic and choking themselves to the point of suffocation or filling their stomachs with so much plastic that they die of starvation (3). According to the Sea Turtle Conservancy, plastic kills over one million marine mammals every year, harms others by means of lacerations or other injuries, and often makes animals susceptible to invasive bacterial infections (2, 3). Invisible plastics (microplastics which are five millimeters or smaller in length) found in marine environments pose a threat to humans as well: studies have found invisible plastics in beer, tap water, salt, and water samples from all oceans around the globe (4). Some of these plastics are carcinogens which can lead to cancer, disrupt the body’s hormones, and inhibit developmental processes (3). On a larger scale, even if marine debris is removed from the ocean, the process of its disposal and degradation can significantly add to the climate crisis. If plastic is burned as a medium of disposal, the burning plastic releases carbon dioxide into the air which increases the amount of carbon emissions in the environment (3). Therefore, scientists are exploring new methods to degrade plastic waste.
In 2016, Japanese researchers identified a bacterial species named Ideonella sakaiensis that degrades polyethylene terephthalate (PET) plastics using enzymes. When the bacteria come into contact with PET plastic, it secretes enzymes that convert the plastic into a terephthalate and ethylene glycol that is then absorbed by the bacteria cell (5). The cell uses these chemicals to create energy and carbon, effectively living off the plastic (7). In 2020, another plastic-eating bacteria strain was found; it is part of the Pseudomonas bacteria family, which is known for its ability to withstand extreme conditions (1). The bacteria is highly effective at degrading polyurethane, a plastic that is harmful to humans when broken down due to the carcinogens and other chemicals released during the process. The bacterium also uses polyurethane as fuel, extracting carbon and nitrogen from it and harnessing them for energy. Profesor John McGeehan, director of the Centre for Enzyme Innovation at the University of Portsmouth in England, explains that “while there is still much work to be done, this is exciting and necessary research that demonstrates the power of looking to nature to find valuable biocatalysts. Understanding and harnessing such natural processes will open the door for innovative recycling solutions” (1). Although these promising discoveries may help us reduce plastic waste and clean our oceans, we still need to limit our plastic use, dispose of it properly, and work together to spread awareness regarding this severe and impending issue. By doing so, we can work towards creating a world in which beachgoers can enjoy their day without encountering plastic trash, marine mammals are safe and healthy in their natural habitat, and climate change is slowed by applying new technologies such as Ideonella sakaiensis in efforts to protect Mother Earth.
Bibliography:
- Carrington, D. (2020, March 27). Scientists Find Bug That Feasts on Toxic Plastic. Guardian News & Media. Retrieved from https://www.theguardian.com/environment/2020/mar/27/scientists-find-bug-that-feasts-on-toxic-plastic.
- Information About Sea Turtles: Threats from Marine Debris. Sea Turtle Conservancy. Retrieved from https://conserveturtles.org/information-sea-turtles-threats-marine-debris/.
- Marine Plastics. International Union for Conservation of Nature. Retrieved from https://www.iucn.org/resources/issues-briefs/marine-plastics#why.
- NOAA. (February 26, 2021). What Are Microplastics? National Oceanic and Atmospheric Administration. Retrieved from https://oceanservice.noaa.gov/facts/microplastics.html.
- Palm, G. J., Reisky, L., Böttcher, D., Müller, H., Michels, E. A. P., Walczak, M. C., Berndt, L., Weiss, M. S., Bornscheuer, U. T., & Weber, G. (April 12, 2019). Structure of Plastic-Degrading Ideonella Sakaiensis MHETase Bound to a Substrate. Nature Communications 10. Retrieved from https://www.nature.com/articles/s41467-019-09326-3.
- Trash Pollution. Ocean Health Index. Retrieved from http://www.oceanhealthindex.org/methodology/components/trash-pollution.
- Tutoru, S. (2016, March). Scientists Discover Plastic-Eating Bacteria That Could Help Clean Oceans. Prescouter. Retrieved from https://www.prescouter.com/2016/03/scientists-discover-plastic-eating-bacteria-that-could-help-clean-oceans/.