Posts here on Life in the City have covered the gamut of impacts of urbanization: the urban heat island, habitat fragmentation, artificial structures, changes in species interactions, and more. One aspect of anthropogenic change we haven’t yet considered is alterations to radioecology, or the ecology of how radioactive compounds affect organisms and the environment. While radioactivity varies naturally over the earth’s surface, human development of nuclear power to provide energy for an increasingly urban population has changed these patterns.
The two most significant anthropogenic events to change the radioactivity of Earth’s surface were incidents at nuclear power plants Fukushima Daiichi in 2011 and Chernobyl in 1986. The incident at Chernobyl released radioactive material over a large portion of Eastern Europe. High concentrations of material now occur in the cities and countryside surrounding the nuclear reactor, which were evacuated. While humans are now largely absent from this area, animal and plant populations are flourishing. One outstanding question is how elevated levels of ionizing radiation in the area may be impacting these organisms.
Germán Orizaola, a senior researcher at the University of Oviedo, has been examining the impacts of radiation on frogs in the Chernobyl area since 2016. When beginning this project, his first observations were that 1) there were abundant frogs in the Exclusion Zone around the plant, and 2) they were all normal! When examining these frogs, however, Germán found that the frogs living inside the zone were much darker than those outside with normal green coloration. Darker coloration caused by higher melanin levels may offer higher resistance to ionizing radiation, a potential adaptation of these frogs.
Germán and colleagues also looked at age of the frogs and the aging process (via telomere length) and did not find any differences between frogs near the plant and those outside the Exclusion Zone. The team is also examining physiological parameters and immune function, but so far they have found no major effects of living in the contaminated area.
Currently, the research team is working on gathering historical genomic data from frog specimens collected prior to the Chernobyl Incident to allow comparisons to contemporary samples. These data will allow them to test for increased mutation rates or accumulation and potentially detect adaptive responses that may be allowing these frogs to live in an environment that remains highly contaminated by radiation.
To keep up to date on Germán’s work, follow him on Twitter (@GOrizaola) or check out his excellent blog!
You can watch the full presentation here:
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