PhD: 2025-OU1 Reconstruction of Indian Monsoon variability in response to Plio-Pleistocene climate

Project highlights

Reconstruct Indian Monsoon variability using deep-sea material
Training in multi-proxy geochemical and/or micropaleontological techniques
International collaboration with IODP expedition scientists

Overview

The Indian Monsoon (IM) is the main seasonal driver of water and food availability, supporting billions of people. The future projection of mean annual summer monsoon rainfall is highly variable under different warming scenarios and an increase in the frequency of extreme precipitation has been suggested if global mean temperature increases ≥ 3 °C1. Our ongoing proxy and modelling work suggest multiple competing controls on IM dynamics (precipitation and wind) during the Plio-Pleistocene linked to atmospheric carbon dioxide (CO2), global cooling, orbital forcing factors and gateway closure2. Nevertheless, the past evolution of IM remains elusive since it is grossly under-represented in Asian monsoon palaeoclimate proxy records. This project aims to produce new proxy records to both fill gaps in our knowledge and test competing external and internal forcing factors affecting IM dynamics across selected intervals of Pliocene-Pleistocene (2-5 million years ago), capturing the prevailing warm, high atmospheric CO2 conditions and gateway closure3.

This project builds on previous and ongoing work to provide flexible opportunities to be trained and employ data/model approach4 to reconstruct past IM variability in response to evolving boundary conditions of Pliocene-Pleistocene climate. Examples include application of a multi-proxy approach to reconstruct IM rainfall/runoff variability, seasonality of monsoon rainfall/runoff and marine biological productivity in response to IM wind variability on orbital timescales from the core IM region of the Bay of Bengal (BoB) or work on integrating existing data with numerical model. The selected International Ocean Discovery Programme (IODP) cores have already been scanned for X-Ray Fluorescence (XRF) elemental ratios and foraminifera assemblage data for the mid-Pliocene (collaborator Robinson). Possibilities of generating new records include pollen and charcoal abundance change to reconstruct continental vegetation, foraminifera/coccolithophore assemblage to reconstruct upper ocean productivity/ecosystem changes, combining microfossil and bulk sediment XRF records with foraminifera based geochemical proxy (oxygen and carbon isotopes and trace elements) records for the targeted interval to ground truth observed trends in continental climate. New data from this project will be compared with published monsoon and climate records to identify the nature of the linkages between vegetation and climate, rainfall and wind components of the IM and/or between Asian Monsoon subsystems and global climate. This project will utilise continuous Plio-Pleistocene sedimentary successions from the BoB (IODP Expedition 353, Sites U1445, U144, U1448 and U1443) to address some of the key questions: what is the response of IM dynamics during the evolving boundary conditions of early- and mid-Pliocene? What is the relationship between vegetation and climate in the monsoon region? How are IM dynamics linked to the other Asian and tropical monsoon regions?

There are two maps shown vertically that captures Indo-Pacific regions between 10°S to 50°N latitudes and 40 °E to 180 °E longitude. The maps show wind vectors and mean precipitation (ranging between 1-17 mm/day. The precipitation colour shading grades from red (maximum) to orange to light yellow (minimum). The maximum rain in the Indo-Pacific region occurs during the northern hemisphere summer (top) and drier conditions during the northern hemisphere winter. There are three green stars showing IM study Sites (U1445 in the north, U1444 which is south of U1445, U1448 in the Andaman Sea and U1443 in the southern Bay of Bengal) and a blue star in the Arabian Sea showing location of data from an ODP Site (722).

Figure 1: Modern rainfall superimposed with wind stress in Asia during the northern hemisphere summer (A) and winter (B) showing different monsoon regions (modified after Wang et al., 2003). Samples are available from IODP Exp 353 Sites (green stars) for this project and published data from ODP site 722 (blue star).

Host

The Open University

Theme

Dynamic Earth

Supervisors

Project investigator

Pallavi Anand, Open University, pallavi.anand@open.ac.uk

Co-investigators

Phil Holden (Open University)
Luke Mander (Open University)
Kate Littler (University of Exeter)
Firoze Quamar (BSIP, India)
Mel Leng (BGS)
Marci Robinson (USGS)
Masafumi Murayama (Kochi University, Japan)

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
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Methodology

The method will include processing of ocean sediments to extract pollen, dinocysts and charcoal5 and the coarse fraction (>150 mm) will be used for picking foraminifera for geochemical work (oxygen and carbon isotopes measurements) in the fully equipped laboratories at The Open University. Coarse fraction samples will be used to extend benthic foraminifer oxygen isotope based Pliocene stratigraphy and for geochemical measurements. Tooth-pick samples could be used for obtaining coccolithophore abundance data at CEREGE (Dr Bolton). The study sites already have XRF scanned bulk sediment geochemical data which will be coupled with micropalaeontological and geochemical data to infer changes in surface water stratification, productivity, ecosystem changes and runoff in response to monsoon variations. Further, targeted intervals will be used for multi-species planktic foraminifera geochemical (coupled trace element and oxygen isotope) data to reconstruct ISM dynamics. Additionally, planktic foraminiferal geochemical data will be utilised to infer orbital and/or seasonal scale variations in rainfall/runoff and put in context with model output4.

Training and skills

DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.

In addition, the student will receive specific training based on selected proxy based study which includes, pollen and charcoal (Mander and Quamar), coccolithophore assemblage data collection and interpretation from (Bolton, CEREGE), oxygen isotope and trace element data collection from (Anand), numerical modelling work (Holden) and work closely with collaborators.

The student will receive project specific training with supervisors and additional OU training.

Specific skills that will be acquired during this project include:

Microfossils assemblage 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/or teaching research methods to year 12 students through Nuffield research placement.

Partners and collaboration

This project will benefit from international collaborations and networking opportunities with IODP 353 expedition scientists. There will be collaboration with scientists working on regional pollen (Firoze Quamar, BSIP, India), coccolithophore (Clara Bolton, CEREGE) and planktic foraminifera-based proxies for oceanographic changes (Marci Robinson, USGS) across the Plio-Pleistocene on the expedition samples.

Further details

Please contact Pallavi Anand (pallavi.anand@open.ac.uk) for further information and informal discussion about this project.

To apply to this project: 

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2025. 
You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities. 
Your application materials, including the CENTA Studentship Application Form 2025, your CV and the Open University application form must be emailed to STEM-EEES-PHD@open.ac.uk. Instructions on how to apply to the Open University are to be found on https://www5.open.ac.uk/stem/environment-earth-ecosystem-sciences/research/phd-students/current-opportunities-and-how-apply, please ensure you read this webpage before applying as you will need to obtain the relevant OU application form from here. Please quote CENTA 2025-OU1 when completing the application form.

  Applications must be submitted by 23:59 GMT on Wednesday 8th January 2025. 

Possible timeline

Year 1

Investigate microfossil-based proxy data collection from the selected study site and familiarise with the taxonomy using available training set and atlas. Obtain training in relevant sample processing. Obtain long term data for the study site. Present data at UK-IODP Annual Meeting.

Year 2

Generate age model data by picking benthic foraminifera of samples from early/mid Pliocene. Obtain micropalaeontological and/or geochemical data from targeted orbital cycles of the Plio-Pleistocene interval. Present data at Pal(a)eoPERCS seminar.

Year 3

Finish remaining analytical work, data analyses, and present results at an international conference and write up thesis and/or prepare manuscript(s).