In a five year study performed by WWF Australia and partners, they have found that there are “alarming” levels of chemicals in sea turtles on the Great Barrier Reef.
The research was initiated after a mass stranding of green sea turtles in 2012, when more than 100 turtles washed ashore dead or dying in Upstart Bay, south of Townsville.
The research was conducted over the five years by collecting water samples, sediment, food, and the blood and shells of turtles to test for a wide range of elements.
In coastal locations, turtles were found to have elevated levels of metals such as cobalt antimony, and manganese in their blood and food. Those turtles that were found with higher levels of chemicals were also noticeably unhealthy.
In Upstart bay, turtles there were seen with cobalt levels as much as 25 times higher than in some coastal areas with little to no human populations and this was also the highest ever recorded for any vertebrate species. Cobalt is vital for animal and human health but in high levels it can become toxic.
The turtles are being directly impacted by human as the chemicals we use on land ends up in the ocean, threatening the clean water that turtles need to survive.
Rain or water used for agricultural washes the chemicals from land, to river and eventually the ocean. Massive amounts of soil and chemicals are washed from farms during heavy rainfalls and all that sediment and excess chemical wash over the reefs. This pollutes and destroys areas of seagrass and coral, where turtles live and feed, and is most likely responsible for the mass deaths of sea turtles in 2012.
The study, known as Rivers to Reefs to Turtles, aims to identify and measure the key pollutants in rivers, the GBR and in the turtles themselves. They hope that the data collected will help them establish a baseline of where and what needs to be addressed to help protect the ocean and its living creatures.
Scientists working on the research have also recommended expanded monitoring of turtle-population health on the Great Barrier Reef “as an indicator of the health of the reef itself”.
Associate Professor Caroline Gaus, from the University of Queensland said to WWF, “There used to be a theory that the ocean was so huge it would dilute contaminants to such an extent that it remained a relatively healthy environment for marine creatures. But people should be aware that many of the chemicals we flush down the toilet, apply to our gardens, spray on crops, or use in factories can end up in turtles and we don’t yet know how it is affecting them.”
WWF’s project partners include the University of Queensland’s National Research Centre for Environmental Toxicology and School of Veterinary Science, James Cook University’s Centre for Tropical Water and Aquatic Research, Griffith University, the Great Barrier Reef Marine Park Authority, Queensland Government agencies, local Traditional Owners and natural resource management groups, and community members.