ORCID
- Hayley R. Manners: 0000-0001-8545-4463
Abstract
The Late Ordovician (~459–444 million years ago) was characterized by global cooling, glaciation and severe mass extinction. These events may have been driven by increased delivery of the nutrient phosphorus (P) to the ocean and associated increases in marine productivity, but it is not clear why this occurred in the two pulses identified in the geological record. We link both cooling phases—and the extinction—to volcanic eruptions through marine deposition of nutrient-rich ash and the weathering of terrestrially emplaced ash and lava. We then reconstruct the influence of Late Ordovician volcanic P delivery on the marine system by coupling an estimate of bioavailable phosphate supply (derived from a depletion and weathering model) to a global biogeochemical model. Our model compares volcanic ash P content in marine sediments before and after alteration to determine depletion factors, and we find good agreement with observed carbon isotope and reconstructed temperature shifts. Hence, massive volcanism can drive substantial global cooling on million-year timescales due to P delivery associated with long-term weathering of volcanic deposits, offsetting the transient warming of greenhouse gas emission associated with volcanic eruptions. Such longer-term cooling and potential for marine eutrophication may be important for other volcanism-driven global events.
DOI Link
Publication Date
2021-12-02
Publication Title
Nature Geoscience
Volume
14
Issue
12
ISSN
1752-0894
Acceptance Date
2021-10-15
Deposit Date
2021-10-19
Embargo Period
2022-06-02
Funding
This work was funded by NERC grant NE/K00543X/1, 'The role of marine diagenesis of tephra in the carbon cycle'. B.J.W.M. acknowledges support from NERC grant NE/S009663/1. T.M.G. acknowledges support of NERC grant NE/R004978/1 and funding from the Alan Turing Institute (EP/N510129/1). We thank C. Rasmussen and S. Leslie for comments, which helped to improve the manuscript. We are grateful to staff of the IODP Gulf Coast Repository and IODP Kochi Core Repository for their assistance during sampling of cores U1396C and U1339D, respectively.
First Page
924
Last Page
929
Recommended Citation
Longman, J., Mills, B., Manners, H., Gernon, T., & Palmer, M. (2021) 'Late Ordovician climate change and extinctions driven by elevated volcanic nutrient supply', Nature Geoscience, 14(12), pp. 924-929. Available at: 10.1038/s41561-021-00855-5
