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Aidan Starr

Research student, School of Earth and Environmental Sciences

Email
starra1@cardiff.ac.uk
Campuses
1.71, Main Building, Park Place, Cardiff, CF10 3AT

Overview

I am an oceanographer interested in the relationship between ocean circulation, carbon cycling and climate change. My focus is on how the oceans of the past were different from today and how this influenced atmospheric carbon dioxide concentrations and climate. Understanding the earth-ocean system during climate events of the past 5 million years could help us understand our planets response to climate change of the present and future!


Interests



  • Paleoceanography 

  • Paleoclimatology

  • Marine Sedimentology

  • Physical Oceanography

  • Biogeochemistry


Research

Research interests

Specific Interests



  • Cenozoic foraminifera: life history, ecology and the paleoclimate signals they carry.

  • Sortable silt paleoflow proxy: the application of grain size analysis for paleoceanographic reconstructions, for example to investigate deep water ventilation and overturning vigour.

  • Isotope geochemistry: using carbon isotope gradients to investigate past water mass distribution and oxygen isotope records to reconstruct ice volume, temperature and salinity.

  • Agulhas Leakage: how did Agulhas Leakage vary in the past, and what effect did this have on overturning circulation and climate?

  • Mid-Pleistocene Transition: a fundamental shift in Earth's climate state when ice ages became more intense and longer. Did ocean stratification play a role in the transition from the 41-kyr world to the 100-kyr world?


Thesis

Changes in ice volume and ocean stratification across the Mid Pleistocene Transition: A multiproxy paleoceanographic study on the Agulhas Plateau

Background


One of the most interesting climate features of the past few million years is the tight link between temperatures and carbon dioxide concentrations. For example, during glacial periods atmospheric COwas substantially lower than during interglacial periods. Explanations for this glacial drop in pCOinvoke an important role for the deep ocean. Models have suggested that the deepest waters of the ocean became isolated from the atmosphere during glacials, trapping CO2 and lowering global temperatures. For deep waters to become isolated, density stratification is required, however little is known about how this evolved across the Pleistocene and Pliocene. This project looks to fill this gap in our knowledge.


Methods


Using samples from the recent International Ocean Discovery Program (IODP) Expedition 361, we are reconstructing the hydrography of the agulhas Plateau. We are using a variety of proxies to achieve this:



  • Foraminiferal stable isotopes (Oxygen and Carbon)

  • Sortable silt grain size analysis

  • Ice rafted debris

  • K/Ar and 40Ar/39Ar analyses

Funding source

NERC GW4+ DTP

Supervisors

Ian Hall

Professor Ian Hall

Head of School, Earth and Environmental Sciences
Research Professor