Human plastic products are constantly found in the world’s oceans, and the microplastics they create are posing serious threats to the entire marine ecosystem.
As twenty-first century humans, we are constantly reminded to watch what we eat. We are wary of macromolecular entities such as cholesterol and saturated fats because of their capabilities of causing chronic lifestyle diseases. Unfortunately, humans across the globe are not the only ones susceptible to the unhealthy intake of substances that may pose long-lasting problems. In the context of Earth’s oceans, marine life from all positions in the food chain are consuming alarming amounts of microplastics. Regrettably, like the tiny macromolecules that humans have to avoid to preserve good health, ingested miniscule microplastics can have significantly unhealthy impacts on aquatic organisms and their ecosystems.
What, exactly, are microplastics? Microplastics are pieces of plastic that measure less than 1 mm (Ziajahromi et al. 2016). Microplastics can be classified into two categories: primary microplastics, which are initially created as plastic products measuring less than 1 mm, and secondary microplastics, which are small pieces of plastic that break off from larger plastic litter (Ziajahromi et al. 2016). Both types of microplastics manage to find their way into the world’s oceans through means such as human littering and water runoff from improperly maintained landfills (Ziajahromi et al. 2016). Once in ocean waters, microplastics are accessible to all sizes and shapes of marine life that can easily mistake these small particles for food and consume them. In their online article “Far more microplastics floating in oceans than thought”, oceanographers Dr. Lavender of Sea Education Association and Dr. van Sebille of Imperial College London remark “…bits of floating microplastic might be ingested by large filter-feeding whales down to nearly microscopic zooplankton” (Lavender & van Sebille 2016), asserting the fact that microplastics are directly entering oceanic food chains at all levels. The fact that microplastics are being consumed by various life forms leads to the pressing questions about how various species respond to microplastics after consumption, how entire ecosystems are ultimately affected, and what can be done to remedy the situation.
In a study published by Water Science & Technology by Dr. Ziajahromi, Dr. Neale, and Dr. Leusch of Griffith University, nine species of aquatic organisms ranging from mussels to European sea bass were exposed to microplastics introduced either in their surrounding water habitats or in their prey sources for varying periods of time. These time periods ranged from a few minutes to several weeks. After the exposure period, the organisms’ physiological and behavioral changes were documented. Out of the nine species, seven displayed noticeable deteriorations in hunting, reproduction, digestive capabilities, and/or overall health (Ziajahromi et al. 2016). In the case of one species, the Common goby, an exposure time of only three minutes was enough to produce a noticeable negative effect on organism hunting effectiveness (Ziajahromi et al. 2016). Although it has been observed in this study that some species are unaffected by prolonged periods of microplastic exposure and some people would argue that evolution will ultimately promote the survival of organisms capable of living in environments containing high amounts of microplastics, these observations and ideas are not nearly enough to corroborate the option of doing nothing about the issue. If microplastics can negatively affect even just one species to the point of bringing about that species’ endangerment or even extinction via poorer health, decreased offspring production, and premature death, a link in the aquatic food chain and ecosystem could be irreparably damaged or even lost. With our dearth of knowledge about the ocean’s ecosystem mechanics, who knows how a change in a species’ population could affect the overall ecosystem, and potentially humans by extension? As scary as it could be, it is entirely possible that the loss of a single key species to microplastic toxicity could result in a rapid domino effect too quick for evolution to respond to, and entire aquatic ecosystems could lose populations and biodiversity at an exponential rate.
Fortunately, the issue of microplastics is internationally recognized, and many national governments are fighting to preserve the biosphere’s aquatic environment via legislation. In 2015, U.S Congress passed the Microbead-Free Waters Act of 2015, effectively outlawing the manufacturing and marketing of cosmetics containing microbead plastics (Ziajahromi et al. 2016). Progressively, more nations are passing similar regulations to stop the oceanic introduction of microplastics. Citizens can also contribute to the solution of cleaning up the world’s oceans by volunteering in cleanup efforts, actively supporting environmentally-friendly legislation, or even simply opting to purchase microplastic-free products. As humans who are responsible for the disturbing state water habitats are in, we can no longer turn a blind eye to the oceans before aquatic biodiversity and organism health completely tank. If humanity is not more proactive about saving marine life, Rachel Carson’s forewarning of a silent spring may have to be accompanied by the horrifying prospect of an empty ocean.
Kara Lavender Law Research Professor of Oceanography, Sea Education Association, & Erik van Sebille Lecturer in Oceanography and Climate Change, Imperial College London. (2016, January 07). Far more microplastics floating in oceans than thought. Retrieved September 08, 2016, from http://theconversation.com/far-more-microplastics-floating-in-oceans-than-thought-51974
Ziajahromi, S., Neale, P. A., & Leusch, F. D. (2016, September 02). Wastewater treatment plant effluent as a source of microplastics: Review of the fate, chemical interactions and potential risks to aquatic organisms. Water Science and Technology, 74(4). doi:10.2166/wst.2016.414 http://wst.iwaponline.com/content/early/2016/09/02/wst.2016.414.abstract