Advancing evolutionary ecotoxicology: single to complex contaminant exposure in Chironomus riparius
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Abstract
In the Anthropocene, human activities such as pollution, habitat loss, and climate change have profoundly altered ecosystems, acting as strong selective forces on exposed organisms. Traditional ecotoxicology has mainly focused on short-term toxic effects, neglecting the long-term evolutionary consequences of chronic exposure to anthropogenic stressors. This dissertation establishes evolutionary ecotoxicology as a practical science integrating evolutionary biology, population genetics, and toxicology.
Using the model species Chironomus riparius, experiments were conducted with single contaminants (Benzo[a]pyrene) and complex sediment mixtures from urban runoff. By combining mutation accumulation lines with whole-genome sequencing, both Benzo[a]pyrene and urban sediments were shown to significantly increase mutation rates and impair key life-cycle traits such as fertility, growth, and population rate. Long-term multigenerational experiments further revealed rapid polygenic adaptation to sediment exposure, accompanied by fitness trade-offs and allele frequency shifts in stress-response genes.
These findings demonstrate that pollutant exposure actively drives evolutionary processes, reshaping genetic diversity and long-term ecological resilience. They highlight the need to integrate evolutionary dynamics into environmental risk assessment frameworks to realistically evaluate ecological risks across generations.