PhD/Master projects in Jimin Yu's group

Please feel free to contact me if you are interested in any (not necesarily all) of the below (both PhD and Master proejects).

  • Application of existing and new methodologies (e.g., foraminiferal trace elements and boron isotopes) for palaeo-reconstructions including ocean carbonate chemistry (e.g., carbonate ion and nutrient) and temperature changes.

  • High resoltuion reconstructions of deep water signals (carbonte ion, temperature, and nutrients) at key locations.

  • Interpretation of paleo proxies along with climate models e.g., LOVECLIM, UVIC, etc, through the existing collaborations.

  • Experience with foraminiferal geochemical analyses in a clean lab for trace elements and boron isotopic analyses for seawater pH reconstructions.
     

Below lists some application criteria.

  • PhD candidates should have some background in any (not necesarily all) of the following fields: Palaeoceanography, Ocean Sciences, and Geochemistry.
  • Prospective students should pass English test as required by the University.
  • See University websites for complete requirements.
  • Candidates are able to work with microfossils using a microscope.
     

Potential projects (2017-)

Project #1. Millennial timescale coupling of climate-Atlantic Ocean circulation

The project aims to reconstruct deep water temperature and salinity changes at millennial to centennial timescales for high sedimentation cores from the Atlantic Ocean. Benthic foraminiferal and ostracod shell Mg/Ca, Li/Mg, and others will be used for reconstructions. The data will allow us to obtain conservative parameters that are critical to understand past ocean circulation changes and, furthermore, their links to climate variabilities and carbon cycling.

Project #2. Southern Ocean nutrient and atmospheric pCO2

It is well known that Southern Ocean processes play a critical role in affecting past atmospheric pCO2 changes. Surface nutrient levels are important to understand the biological pump efficiency in the past. However, despite extensive effort, it remains highly debated regarding the history of the Southern Ocean nutrient changes. One reason is that scientists are short of cores with enough carbonate materials to work on. This project aims to apply geochemical proxies (including Cd/Ca and d15N) to two special cores collected from Polar Antarctic Zone (~70oS) near the deep water formation regions. We are lucky in that these cores have enough foraminiferal shells for analyses. The materials will surely provide new insights into mechanisms for past atmospheric pCO2 changes.

Project #3. Holocene climate-carbon cycle using super high-resolution reconstructions

Compared to the last deglacial period, the Holocene (~0 - 10,000 years ago) climate has remained relatively stable. However, there have been significant changes in ocean circulation and carbon cycle as registered by high-sedimentation archives. For example, ice core records show ~20 ppm increase in atmospheric pCO2 during the last ~8,000 years, but the mechanisms responsible for this change and their links to climate/ocean circulation remain elusive. To investigate Holocene climatic changes, high-sedimentation-rate cores are necessary. We have secured sediment cores with sediment rates up to 50 cm/kyr from key locations in the Atlantic Ocean with which we hope to provide new insights into processes controlling the Holocene climate and carbon cycle. The project aims to use various paleoceanographic tools to reconstruct mid- and deep-depth physical (temperature, salinity) and chemical (nutrient and carbonate ion concentrations) properties at various locations. Along with the use of intermediate complexity models (e.g., LOVECLIM, UVIC, etc), these new data will afford to identify the role of the Atlantic Ocean in controlling the regional and global climate during the Holocene.

Research areas

Research topics in the group are generally flexible, aiming to understand the global carbon cycle, ocean circulation changes, and marine physiochemical evolution on various timescales during Quaternary.

Research will have access to state-of-the-art trace metal and isotopic analysis facilities that are operated by the Ocean & Climate Geosciences:

(LA-)ICP-MS
Neptune MC-ICP-MS
AMS for radiocarbon dating and tracing
Foraminiferal oxygen and carbon isotopes
Low boron-blank clean laboratories (supervised by J Yu)
XRF core scanner

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