COMPREHENSIVE CALIBRATION OF CRITICAL PALEOCEANOGRAPHIC PROXIES

Lead Research Organisation: University of Southampton
Department Name: School of Ocean and Earth Science

Abstract

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 atmosphere). 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 for a wide range of geochemists internationally.

Publications

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Bridgestock L (2018) Controls on the barium isotope compositions of marine sediments in Earth and Planetary Science Letters

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German CR (2016) Hydrothermal impacts on trace element and isotope ocean biogeochemistry. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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Hernandez-Sanchez M (2012) Signature of organic matter exported from naturally Fe-fertilised oceanic waters in Deep Sea Research Part I: Oceanographic Research Papers

 
Description Trace metal supply from ocean sediments is a significant source of iron to the oceans
Exploitation Route Earth system models
Sectors Environment

URL http://www.southampton.ac.uk/oes/news/2013/11/exploring_our_oceans_oceanography_mooc.page
 
Description Citation in Environment Audit Committee report
Geographic Reach Multiple continents/international 
Policy Influence Type Citation in other policy documents
Impact The EAC Committee report urges Government action to stop using seas as a sewer. Specific impact of my contribution included a statement that Govt should commit not to pursue licences for seafloor massive sulfides within UK jurisdiction. The UK should use its significant influence to impose a moratorium on licences outside UK jurisdiction and work with the International Seabed Authority to ensure robust Environmental Impact Assessments that are based on the precautionary principle and make the best use of available scientific evidence.
URL https://publications.parliament.uk/pa/cm201719/cmselect/cmenvaud/980/980.pdf
 
Description Free Online Course: Exploring our Oceans 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Exploring our Oceans has reached a global audience (over 35,000 sign ups), and our learners have a wide range of backgrounds and motivations for taking the course.

The course design and FutureLearn platform ensures accessibility for all. Videos introduce key concepts at a basic level, and accompanying text expands on video content. Extended reading opportunities and links to external organisations, provide signposting for broader learning and
engagement. Links to open access papers stretch participants for deeper advanced learning.

Our postgraduate facilitators develop their public engagement skills and confidence via asynchronous discussion of emotive subjects within the community. Delivering such a course has enabled the Faculty to test new technologies and activities at scale before use with on-campus students.
Nelson Mandela University is a contributor to the course as part of a Newton grant (ESRC: ES/N013913/1 Capacity building and PhD student partnership with Nelson Mandela University in the Marine and Maritime sectors, 2015-2018). Part of the legacy of this project includes sharing learning resources and capacity building for developing online learning in South Africa. Summary of Impacts • Maintained a significant 4 year presence on a global online platform
• Boosted applications to undergraduate programmes and engaged with our incoming students during the recruitment cycle
• Promoted our research in deep sea exploration
• Built on a 4*REF2014 Impact Case Study: Exploring the Deep: Public Engagement with Deep Ocean Research and provided clear metrics on reach and impact of learner experience.
• Developed our graduate students' skills in communication, impact and engagement
• Delivered our Newton funded project goals to transform marine postgraduate education in South Africa in partnership with Nelson Mandela University,
• Helped to build our international partnerships worldwide
Year(s) Of Engagement Activity 2014,2015,2016,2017,2018
URL https://www.futurelearn.com/courses/exploring-our-oceans
 
Description Life Scientific BBC Radio 4 
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 Interview with Jim Al-Khalili discussing all elements of current and past funding and impact.
Year(s) Of Engagement Activity 2018
URL https://www.bbc.co.uk/programmes/b0b6m5y3