Heavy Metal Toxicity: A Major Driver of Past Biodiversity Crises?

Whether today’s heavy metal pollution represents an unprecedented threat to biodiversity, in Earth’s history remains an open question. Here, we reassess the state-of-the-art research to evaluate whether heavy metal toxicity played a major role in past extinction events. Although there is evidence to heavy metal loading during several past biotic crises, direct causal links to extinctions are still lacking. Recent studies are beginning to reveal potential connections in terrestrial ecosystems, while geochemical signatures point to heavy metal impacts in marine environments. Nonetheless, it remains unclear whether modern heavy metal toxicity represents a uniquely severe threat to biodiversity in Earth’s history.