Editing Extinction event (section)

====Hydrogen sulfide emissions from the seas====
Kump, Pavlov and Arthur (2005) have proposed that during the [[Permian–Triassic extinction event]] the warming also upset the oceanic balance between [[photosynthesis]]ing plankton and deep-water [[sulfate-reducing bacteria]], causing massive emissions of [[hydrogen sulfide]], which poisoned life on both land and sea and severely weakened the [[ozone layer]], exposing much of the life that still remained to fatal levels of [[UV radiation]].<ref>{{cite journal | vauthors = Berner RA, Ward PD |title=Positive Reinforcement, H2S, and the Permo-Triassic Extinction: Comment and Reply: COMMENT |journal=Geology |date=1 January 2006 |volume=34 |issue=1 |pages=e100 |doi=10.1130/G22641.1 |bibcode=2006Geo....34E.100B |doi-access=free }}</ref><ref>{{cite journal | vauthors = Kump LR, Pavlov A, Arthur MA | year = 2005 | title = Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia | journal = Geology | volume = 33 | issue = 5| pages = 397–400 | doi=10.1130/g21295.1 |bibcode = 2005Geo....33..397K }} Summarised by Ward (2006).</ref><ref name="Ward 2006"/>