DEEP IN THE JUNGLE

Gold - shiny, coveted and valuable. In addition to worldwide mining in large industrial mines, gold is extracted in many tropical countries by small-scale artisanal mining. This does not involve the use of machines, but often substances such as mercury. This is not only illegal - it also has serious consequences for the environment, humans and animals.

In illegal gold mining, mercury is used to dissolve the precious metal from the rock using a chemical reaction. In the process, the toxic heavy metal enters the surrounding waters and is absorbed by living organisms. The organisms accumulate the mercury in their bodies. Via the food cycle, the concentration of the poison steadily increases along the food chain. At the top of this chain are caimans, in which particularly high levels of heavy metals are measured.

ROSANNA IN ACTION FOR CAIMANS

In French Guiana, a region in north-eastern South America, Rosanna Mangione and her colleague Jérémy Lemaire are investigating mercury levels in caimans on behalf of the University of Vienna. Mercury cannot be broken down by the body and even in small quantities damages vital organs such as the brain and liver. It also has a negative impact on reproduction.

For their research project, Rosanna and Jérémy mark the caimans so that they can identify and observe the animals more easily. “Our tagging and recapture data form the basis for the first long-term study to assess the population development of caimans in French Guiana,” explains Rosanna. The results so far show that the offspring of contaminated caimans are smaller than those of their uncontaminated conspecifics. “Caimans that hatch larger have significantly better chances of survival,” Rosanna continues. In addition to the health of the animals, the researchers are also investigating their habitat to find out how heavy metal pollution affects the entire ecosystem.

PROTECTING PEOPLE AND NATURE THROUGH EDUCATION

An important aspect here is that sustainable protection requires a holistic view of the ecosystem: “The establishment of nature reserves, for example, is of little use if heavy metals are released directly next to the protected area. This is because they then enter the nature reserve via precipitation or a watercourse,” says Rosanna. With their research, Rosanna and Jérémy want to promote a better understanding of the complex relationships in the ecosystem. The knowledge gained can help communities and governments to take appropriate measures to effectively protect caimans, people and the environment.

You can find more information about Rosanna and Jérémy's work here.