Why do large mercury fall flat

Heavy Metals: Did Mercury Contribute to Mass Extinction?

Mercury, today one of many toxins distributed in the environment, could once have played an important role in the end of the world. On the basis of damaged fern spores in deposits, a working group led by Sofie Lindström from the Geological Survey of Denmark and Greenland has now come to the conclusion that the highly toxic heavy metal was involved in one of the great mass extinctions about 200 million years ago. As the team reports in "Science Advances", it found several sections in sediment samples from Denmark and northern Germany with many times higher mercury concentrations. These coincide with carbon isotope anomalies that arise during dramatic crises in the biosphere.

During this event, which marks the boundary between the Triassic and Jurassic geological ages, about a third of all animal groups in the sea died out; in addition various large groups of vertebrates on land, including large amphibians and almost all crocodile relatives. The real cause of the mass extinction was gigantic volcanic eruptions when the supercontinent Pangea broke up - the released carbon dioxide caused a dramatic climate change that put the world of the Triassic under. Normally, the high mercury concentrations at this turn of the century are only evidence of these outbreaks, but Lindström and her team also found enormous amounts of deformed fern spores in the deposits - an indication of influences that damage the genetic material.

This article is included in Spectrum - The Week, 44/2019

It just so happens that mercury does exactly that: As the working group notes, it is the most genetically damaging element on the periodic table. This coincidence suggests a connection that is characteristic of this mass extinction, especially since no comparable amounts of mutated spores were found at the end of the world 50 million years earlier at the beginning of the Triassic. However, the researcher warns against too far-reaching conclusions: Mercury was probably one factor among several. It is possible that the metal weakened particularly large predators. Mercury accumulates in the food chain; nowadays you can see high concentrations in predatory fish such as tuna, for example. However, it does not come from volcanoes.