Reply to Butterfield: The Devonian radiation of large predatory fish coincided with elevated athospheric oxygen levels
2011 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 9, E29- p.Article in journal (Refereed) Published
We welcome this opportunity to clarify the conclusions and implications of our recent publication in PNAS. Butterfield (1) raises four issues regarding the oxygenation of the Paleozoic Earth's surface and its correlation to animal evolution. Our geochemical and paleontological data supported ocean oxygenation in the Silurian-Early Devonian (2), a critical transition in Earth history that influenced biogeochemical cycles and biological systems.
First, Butterfield suggests that evidence of charcoal in late Silurian rocks is incompatible with our claim that the earlier Paleozoic atmosphere had oxygen levels below 50% PAL (present-day atmospheric level). This counterargument rests on the assumption that the “fire window” of 62–166% PAL oxygen is well defined, but this is not the case (3).
Place, publisher, year, edition, pages
2011. Vol. 108, no 9, E29- p.
Research subject Geochemistry
IdentifiersURN: urn:nbn:se:su:diva-65878DOI: 10.1073/pnas.1018818108ISI: 000287844400002OAI: oai:DiVA.org:su-65878DiVA: diva2:465793