ORCID Profile
0000-0003-4706-1233
Current Organisations
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
,
University of Bristol
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Publisher: American Geophysical Union (AGU)
Date: 03-2019
DOI: 10.1029/2018PA003420
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-01-2020
Abstract: Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. The best model fits to the data required most outgassing to occur before the impact. When combined with other lines of evidence, these models support an impact-driven extinction. However, volcanic gases may have played a role in shaping the rise of different species after the extinction event. Science , this issue p. 266
Publisher: Elsevier BV
Date: 11-2016
Publisher: American Geophysical Union (AGU)
Date: 04-2015
DOI: 10.1002/2014GC005514
Publisher: Elsevier BV
Date: 02-2013
Publisher: Springer Science and Business Media LLC
Date: 11-02-2015
DOI: 10.1038/NATURE14155
Abstract: Atmospheric CO2 fluctuations over glacial-interglacial cycles remain a major challenge to our understanding of the carbon cycle and the climate system. Leading hypotheses put forward to explain glacial-interglacial atmospheric CO2 variations invoke changes in deep-ocean carbon storage, probably modulated by processes in the Southern Ocean, where much of the deep ocean is ventilated. A central aspect of such models is that, during deglaciations, an isolated glacial deep-ocean carbon reservoir is reconnected with the atmosphere, driving the atmospheric CO2 rise observed in ice-core records. However, direct documentation of changes in surface ocean carbon content and the associated transfer of carbon to the atmosphere during deglaciations has been hindered by the lack of proxy reconstructions that unambiguously reflect the oceanic carbonate system. Radiocarbon activity tracks changes in ocean ventilation, but not in ocean carbon content, whereas proxies that record increased deglacial upwelling do not constrain the proportion of upwelled carbon that is degassed relative to that which is taken up by the biological pump. Here we apply the boron isotope pH proxy in planktic foraminifera to two sediment cores from the sub-Antarctic Atlantic and the eastern equatorial Pacific as a more direct tracer of oceanic CO2 outgassing. We show that surface waters at both locations, which partly derive from deep water upwelled in the Southern Ocean, became a significant source of carbon to the atmosphere during the last deglaciation, when the concentration of atmospheric CO2 was increasing. This oceanic CO2 outgassing supports the view that the ventilation of a deep-ocean carbon reservoir in the Southern Ocean had a key role in the deglacial CO2 rise, although our results allow for the possibility that processes operating in other regions may also have been important for the glacial-interglacial ocean-atmosphere exchange of carbon.
Location: Germany
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Michael Henehan.