Overview

Project Highlights:

  • Reconstruct first high-resolution Pliocene Indian monsoon runoff
  • Training in multi-proxy geochemical and micropaleontological reconstructions
  • International collaboration with IODP expedition scientists

The Indian Monsoon, a subsystem of the Asian Monsoon, is one of the best examples of coupling between solid earth, ocean and atmospheric processes. The Indian Summer Monsoon (ISM) precipitation is the main seasonal driver of water availability, supporting billions of people. The future projection of mean annual ISM rainfall is highly variable under different warming scenarios and an increase of three-fold in the frequency of extreme precipitation over India land has been suggested if global mean temperature increases ≥ 1.5 °C1. In order to improve our understanding, rainfall response during past warm climates, beyond the instrumental record, is needed. Our ongoing work in the Plio-Pleistocene indicates variable ISM dynamics linked to warming2, global cooling and/or orbital forcing factors (from International Ocean Discovery Program (IODP) expedition 353 Sites in the Bay of Bengal/BoB). However, studies from the early/mid-Pliocene (3 to 5 Ma) are needed to capture the response during the prevailing warm and high atmospheric carbon dioxide (CO2) conditions3.

This project, therefore, will apply a multi-proxy approach to reconstruct ISM rainfall/runoff, seasonality of monsoon rainfall/runoff and ISM wind variability on orbital and/or tectonic timescales from the core ISM region of the BoB. The selected IODP sites already have X-Ray Fluorescence (XRF) elemental ratios and diatom proxy data (for the northern BoB site). New records from this project will be compared with published monsoon and climate records to identify the nature of the linkage between Asian Monsoon subsystems and global climate. This project will primarily utilise newly drilled continuous sedimentary successions from the BoB (IODP Expedition 353, Sites U1444, U1445 and U1443 and ODP site 722 in the Arabian Sea) to address some of the key questions: what is the role of elevated CO2 and climate on ISM rainfall and wind driven productivity? How are ISM dynamics linked to the other Asian and global monsoon regions?

 

Modern rainfall superimposed with wind stress in Asia during the northern hemisphere summer and winter showing different monsoon regions (modified after Wang et al., 2003). Samples are available from IODP Exp 353 Sites (yellow stars) and ODP site 722 (blue star) for this project.

Methodology

The deep-sea mud samples will be washed and the larger fraction (>150 um) will be used for picking benthic and planktic foraminifera for geochemical work (oxygen and carbon isotopes measurements on carbonates) and shell size from the same interval on a split of the same sample (as part of the ongoing IODP project) in the fully equipped laboratories at The Open University. Benthic foraminifer oxygen isotope measurements will be used to develop an early Pliocene stratigraphy. Tooth-pick samples will be used for coccolithophore assemblage and size and mass work at CEREGE (Dr Bolton). The study sites have existing XRF scanned geochemical data which will be coupled with coccolithophore and foraminifera (in collaboration) assemblage, coccolithophore and planktic foraminifera mass and size data to infer changes in surface water stratification and productivity and runoff in response to monsoon variations. Additionally, planktic foraminiferal geochemical data will be utilised to infer orbital scale and seasonal extremes in rainfall/runoff2.

Training and Skills

addition to CENTA2 training events, the student will receive specific training on coccolithophore assemblage and mass and size work at CEREGE (Dr Bolton) and work closely with project partner (Dr Littler) for stratigraphy and comparison with organic proxies (Dr Littler).

The student will receive project specific training with supervisors (PA and MB) and OU offers a diverse set of training courses throughout their PhD.

Specific skills that will be acquired during this project include:

  • Conducting research on newly discovered deep-sea sediments (IODP Expedition 353) and working with an international team
  • Nannofossil and microfossil assemblages and geochemical analyses
  • Data handling and interpretation from a wide variety of sources
  • Scientific communication through writing, poster and oral presentations to academic and non-academic audiences
  • Co-supervision on your own devised OU’s master’s project and teaching research methods to A level Nuffield funded summer students.

 

Timeline

Year 1: Obtain training in sample processing of core material for microfossils (taxonomy), inorganic geochemical and stable isotope techniques. Generate benthic oxygen isotope stratigraphy and interpret existing XRF data. Attend UK-IODP annual meeting.

Year 2: Present elemental results at the Geochemistry Research in Progress meeting (UK) and prepare a manuscript based on age model, coccolithophore productivity and XRF data. Generate stratification and productivity records from the BoB sites. Carry out statistical analyses of generated data set. Write and submit first manuscript.

Year 3: Finish remaining analytical work, data analyses, and write draft of second manuscript. Present results at an international conference based on submitted manuscript. Carry out CENTA placement.

Year 4: Write up thesis and respond to reviewers of the submitted manuscripts.

 

Partners and collaboration (including CASE)

This project will benefit from international collaborations and networking opportunities with IODP 353 expedition scientists. In particular, there will be collaboration with scientists working on the Plio-Pleistocene transition for stratigraphy, foraminifera assemblage (Marci Robinson, USGS), diatom productivity (Oscar Romero, AWI, Germany) proxies and monsoon modelling (Phil Holden and Emmeline Gray, OU).

Further Details

Students should have a background in palaeoclimate or micropalaeontology. Experience of microscopy work and a strong interest in palaeoclimate proxy are highly desirable. The successful student will join a well-established team researching in rapid global warming events (http://www.open.ac.uk/science/environment-earth-ecosystems/research/palaeoenvironmental-change/rapid-global-warming-events) in Palaeoenvironmental change group and a vibrant  postgraduate community at the Open University.

Please contact Dr Pallavi Anand [pallavi.anand@open.ac.ukfor further information.

Applications should include: