Lead Research Organisation: University of Bristol
Department Name: Chemistry


Humans have directly recorded information about only a narrow range of climate. Evidence for a much larger range of possible Earth climate, and for thresholds within the climate system, come from paleoclimate records derived from archives such as ice and sediment cores. Assessing the range of such climates and the mechanisms that caused them is of fundamental importance if we are to accurately predict future climate. Such paleoclimate work relies absolutely on the application of proxies. We cannot measure environmental variables such as ocean circulation directly for past times, but we can find chemical proxies for these variables in paleo-archives. Development and calibration of these proxies is critical to paleoclimate. But such calibration can sometimes lag behind their application, leading to uncertain reconstructions of the past. The work proposed here seeks to address this issue with an explicit focus on calibration of critical proxies for paleoceanography. The proposal brings together researchers with a variety of chemical specialities, but all with a strong track record for proxy calibration work. Although each of these researcher also applies proxies to paleoclimate questions, this is not a paleoclimate proposal, but is focused on understanding the modern water-column and upper-sediment behaviour of chemical-species used as paleoproxies. We will understand the geochemistry that links the final sediment composition to climate variables, and assess the limitations on these links so that proxies are not applied inappropriately. We will focus on a limited number of proxies, each of which has clear (and, in most cases, demonstrated) potential to provide important information about the past. These proxies, if accurately calibrated, will provide information about the pattern and rate of past ocean circulation, and about the composition, flux and nutrient utilisation of past biological productivity (which sets the removal of carbon from the ocean). They therefore have tremendous potential to inform us about the role of the oceans in past climate, both through the transport of heat and carbon. The proxy calibration work proposed here will allow that potential to be better and more accurately realized. The geochemical focus of this proposal is also central to a major new international research programme investigating the marine cycling of trace elements and isotopes / GEOTRACES. A research cruise in the South Atlantic is proposed here to allow collection of water-column and sediment samples for the proxy calibration work. This cruise will form a UK component of the GEOTRACES programme. Although funds are only sought for the calibration of critical paleoproxies in this proposal, the research cruise will be a platform for a wide range of other biogeochemical research. Such work might include assessment of biologically significant metal fluxes at ocean margins, chemical transport in deep-water masses, and the controls on micronutrient supply to the surface waters of the low-dust South Atlantic. We will ensure, though our existing involvement in the GEOTRACES programme, that the widest possible range of such research is achieved on the cruise, making this an important research cruise to a wide range of geochemists internationally.


10 25 50
Description Observation that glycerol dialkyl glycerol tetraether (GDGT) lipid distributions vary with water column depth, implying the existence of multiple pelagic Thaumarchaeotal communities and with major implications for the interpretation of GDGT-based palaeo-temperature reconstruction.

Observation that lipid distributions are rapidly and dramatically altered during sinking and shallow sedimentary diagenesis.

Discovery of new relationships between algal carbon isotope fractionation and nutrient regime; the implication is that trace metals exert a strong control over carbon assimilation.
Exploitation Route Developing collaborations with renewable energy sector: Our results highlight the important role of atmospheric carbon dioxide as a climate driver, emphasising the need to move to a carbon neutral economy. The observation regarding GDGTs is fundamentally informing the entire scientific community's application of the TEX86 temperature proxy.
Sectors Environment

Description The primary impact of this research reflects its title's aspirations: it has helped us better understand a range of organic biomarker-based palaeoceanographic and palaeoclimatic proxies. In particular, it has transformed our understanding of the widely used TEX86 proxy for sea surface temperature by unambiguously showing that the distributions of ether lipids on which the proxy is based vary markedly through the water column - and that this variation is incorporated into sediments. This means that TEX86 is not truly a SST proxy and its application must be carefully considered. By extension, the work now underpins TEX86-based reconstructions of earth system sensitivity, a climate parameter of great societal interest.
First Year Of Impact 2012
Sector Environment
Impact Types Societal

Description Living in the Futures Past 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact During 2015-2016, Pancost was interviewed by Susan Kucera on past and future climate change. Those conversations - as well as others - were compiled into the film Living in Futures Past, released at film festivals in early 2018. The film was produced by and stars Jeff Bridges. Info available at: and
Year(s) Of Engagement Activity 2018