Science news driblet:
Toxic metals such as iron, lead and arsenic may have helped cause mass extinctions in the world’s oceans millions of years ago, according to recent research from the U.S. Geological Survey, the National Center for Scientific Research, France; and Ghent University, Belgium. These findings largely came from studying “teratological” or malformed fossil plankton assemblages corresponding to the initial stages of extinction events approximately 420 million years ago that killed off most marine species
At that time, several mass extinction events shaped the evolution of life on our planet. Some of these short-lived events were responsible for eradication of up to 85 percent of marine species, however the exact kill-mechanism responsible for these crises remains poorly understood.
In a paper just published in Nature Communications, the scientists present evidence that malformed fossil remains of 415 million- year-old marine plankton contain highly elevated concentrations of heavy metals of the kind that can cause morphological abnormalities in today’s marine life. This led the authors to conclude that metal poisoning caused the observed malformation and may have contributed to the extinction of these and many other species.
The entire paper is available here.
Please note, these extinction events were 420 million years ago (or so), not recent.