Ammonium ocean following the end-Permian mass extinction

Sun, Y. D.; Zulla, M. J.; Joachimski, M. M.; Bond, D. P.G.; Wignall, P. B.; Zhang, Z. T.; Zhang, M. H.

Abstract

The aftermath of end-Permian mass extinction was marked by a ~5 million year interval of poorly-understood, extreme environments that likely hindered biotic recovery. Contemporary nitrogen isotope variations are considered, using a new conceptual model, to support a scenario that shows intensive nitrate-removal processes gradually depleted the global oceanic nitrate inventory during long-lasting oceanic anoxia. Enhanced nitrogen fixation shifted the oceanic nitrogenous nutrient (nutrient-N) inventory to an ammonium dominated state. Ammonium is toxic to animals and higher plants but fertilizes algae and bacteria. This change in ocean chemistry could account for the intense and unexplained losses of nektonic taxa and the proliferation of microbial blooms in the Early Triassic. The transition from a nitrate ocean to an ammonium ocean was accompanied by a decrease in respiration efficiency of organisms and a shrinking oceanic nutrient-N inventory, ultimately leading to generally low productivity in the Early Triassic oceans. These unappreciated nutrient changes during episodes of prolonged ocean anoxia may be the key life-limiting factor at such times.

Citation

Sun, Y. D., Zulla, M. J., Joachimski, M. M., Bond, D. P., Wignall, P. B., Zhang, Z. T., & Zhang, M. H. (2019). Ammonium ocean following the end-Permian mass extinction. Earth and planetary science letters, 518, 211-222. https://doi.org/10.1016/j.epsl.2019.04.036

• Journal Article Type: Article
• Acceptance Date: Apr 23, 2019
• Online Publication Date: May 17, 2019
• Publication Date: Jul 15, 2019
• Deposit Date: Apr 24, 2019
• Publicly Available Date: May 18, 2020
• Journal: Earth and Planetary Science Letters
• Print ISSN: 0012-821X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 518
• Pages: 211-222
• DOI: https://doi.org/10.1016/j.epsl.2019.04.036
• Keywords: Ocean anoxic event; Nitrogen cycle; Early Triassic; Ammonium ocean
• Public URL: https://hull-repository.worktribe.com/output/1641616
• Additional Information: This is the accepted manuscript of an article published in Earth and planetary science letters. The version of record is available at the DOI link in this record