2 Oct 2018 - 50 years of plastic waste has brought the world’s oceans to a tipping point in which, by 2050, there will be more plastic in the oceans than there are fish (by weight). Sea turtles are a specific point of concern about ocean plastics, as the intestinal tracts of these large marine animals get blocked when they mistake soft plastics for jellyfish. Headlines about sea turtle deaths on the world’s beaches and community reactions seem to come at us daily. Because of their propensity to ingest debris, sea turtles can be bioindicators of the global marine debris problem, helping us to understand the extent of the plastic problem in our world’s oceans. However, recent research suggests that more can be done to grasp the effects of plastics and other refuse on sea turtles.
Scientists and the public in general are troubled about the increase in ocean trash and the effects of plastics on marine life. Ingestion of marine debris is an increasingly significant problem for marine wildlife and is known to affect more than 170 marine species worldwide. Many marine creatures can’t distinguish common plastic items from food, so they starve because they can’t digest the plastic that fills their stomachs.
Scientific literature about sea turtles tends to correlate their overall health and longevity to the stability and sustainability of the marine environment. Jennifer Lynch of the National Institute of Standards and Technology (NIST) recently published a paper titled, “Quantities of Marine Debris Ingested by Sea Turtles: Global Meta-Analysis Highlights Need for Standardized Data Reporting Methods and Reveals Relative Risk.” In it, she argues that research on turtles over the last 50 years has often only focused on the presence or absence of debris while neglecting to note the amount of garbage found in each turtle gut. Lynch concludes from her own research that trash in turtles should really be handled no differently than any other kind of toxicological issue.
The Various Effects of Plastics on Sea Turtles
Toxicologists often paraphrase Paracelsus, a Renaissance physician who emphasized the value of observation in combination with received wisdom, by saying “the dose makes the poison.”
When doctors determine the risks of environmental toxins on a patient, they base their conclusions on the amount of the substance in question and the patient’s attributes such as weight, age, and size. Lynch explains that, while some people have difficulty imagining plastic as a toxic substance, for turtles, plastic very well could be poisonous to marine life.
“But right now, we don’t know the thresholds,” she said in an article for Science Daily. “We don’t know at what point plastic causes physiological, anatomical, or toxicological impacts on these creatures.”
But the problem may be easier to measure than other exposure issues, provided that the right data is gathered in future studies. Turtles could eventually provide important clues to where garbage is worst. Her research provides some suggestions for improving the science of turtle research.
The NIST researcher says that future sea turtle studies should include all of the following and identify:
- whether or not toxins were discovered in a sea turtle’s gut
- how much trash was discovered in the turtles’ digestive systems
- physiological details like whether the animal was a small hatchling or a large adult
- the turtle species, as different kinds of sea turtles travel in different parts of the oceans