Methanogenic Burst in the End-Permian Carbon Cycle
Methanogenic burst in the end-Permian carbon cycle Daniel H. Rothmana,b,1, Gregory P. Fournierc, Katherine L. Frenchb, Eric J. Almc, Edward A. Boyleb, Changqun Caod, and Roger E. Summonsb aLorenz Center, bDepartment of Earth, Atmospheric, and Planetary Sciences, and cDepartment of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139; and dState Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China Edited by John M. Hayes, Woods Hole Oceanographic Institution, Woods Hole, MA, and approved February 4, 2014 (received for review September 27, 2013) The end-Permian extinction is associated with a mysterious disrup- and its perturbation to the carbon cycle but also to amplify the tion to Earth’s carbon cycle. Here we identify causal mechanisms via development of marine anoxia. Taken as a whole, these results three observations. First, we show that geochemical signals indicate reconcile an array of apparently disparate observations about the superexponential growth of the marine inorganic carbon reservoir, end-Permian event. coincident with the extinction and consistent with the expansion of a new microbial metabolic pathway. Second, we show that the effi- Growth of the Marine Carbon Reservoir cient acetoclastic pathway in Methanosarcina emerged at a time sta- Fig. 1A displays the carbon-isotopic record in Meishan, China tistically indistinguishable from the extinction. Finally, we show that (5). Immediately preceding the extinction event, the isotopic com- nickel concentrations in South China sediments increased sharply at position δ1 of carbonate carbon declines by about 7‰ during the extinction, probably as a consequence of massive Siberian volca- a period of about 100 thousand years (Kyr), first slowly, and sub- nism, enabling a methanogenic expansion by removal of nickel lim- sequently rapidly.
[Show full text]