Atmospheric Carbon Injection Linked to End-Triassic Mass Extinction

http://news.sciencemag.org/sciencenow/2011/07/did-greenhouse-gasses-unleash-th.html?ref=hp

Ruhl, M., Bonis, M. R., Reichart, G-.R., Sinninghe Damste, J. S., and W. M. Kürschner. 2011. Atmospheric Carbon Injection Linked to End-Triassic Mass Extinction. Science 333:430-434. DOI:10.1126/science.1204255.

Abstract - The end-Triassic mass extinction (~201.4 million years ago), marked by terrestrial ecosystem turnover and up to ~50% loss in marine biodiversity, has been attributed to intensified volcanic activity during the break-up of Pangaea. Here, we present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval. These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 103 gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.