"Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction,"...the nickel was sourced from the volcanic terrain, very likely carried by aerosol particles and deposited in the ocean, where it dramatically changed the chemistry of seawater and severely disrupted the marine ecosystem.
"The study results provide strong evidence that nickel-rich particles were aerosolized and dispersed widely, both through the atmosphere and into the ocean," Wasylenki said. "Nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life."
Prior to this study, the connection between Siberian Traps flood basalt volcanism, marine anoxia and mass extinction was rather vague, but now we have evidence of a specific kill mechanism.