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Philos Trans R Soc Lond B Biol Sci. 2016 May 19;371(1694). pii: 20150510. doi: 10.1098/rstb.2015.0510.

Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study.

Author information

1
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA michael.henehan@yale.edu.
2
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA.
3
Department of Earth Sciences, University of St Andrews, Irvine Building, St Andrews KY16 9AL, UK.
4
Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.

Abstract

Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO2 concentrations (pCO2). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO2 To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous-Palaeogene (K-Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K-Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.

KEYWORDS:

Cretaceous–Palaeogene extinction; LOSCAR; biogeochemical cycling; bolide impact; ecosystem function; mass extinction

PMID:
27114586
PMCID:
PMC4843705
DOI:
10.1098/rstb.2015.0510
[Indexed for MEDLINE]
Free PMC Article

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