PhD Oral Defense of Sujata Murty: Reconstructing Surface Water Mixing and Climate using Records of Sea Surface Salinity and Radiocarbon from Southeast Asian Corals

PhD Oral Defense of Sujata Murty: Reconstructing Surface Water Mixing and Climate using Records of Sea Surface Salinity and Radiocarbon from Southeast Asian Corals

Event Type: 

  • Oral Defense

Venue: 

ASE 3D Visualisation Laboratory (N2-B1c-16c)

Date: 

30 August, 2018 - 10:30 to 11:30

About the Event: 

The Indonesian Seas provide an oceanic pathway, the Indonesian Throughflow (ITF) that transports heat and freshwater from the tropical Pacific Ocean into the Indian Ocean. The ITF thus impacts air-sea heat exchange, inter-ocean heat distribution, and regional and global climate systems. However, during the East Asian Winter Monsoon (EAWM) buoyant South China Sea waters inhibit surface ITF flow and reduce heat transport to the Indian Ocean. Records of past monsoon influences on surface water variability in the Indonesian Seas are therefore critical to better understand the interactions between monsoon-driven ocean circulation and Indo-Pacific climate. I present multi-century, coral-derived records of sea surface salinity and ocean circulation to examine the role of the EAWM in surface water mixing variability throughout the Makassar and Lombok Straits, located along main ITF pathways. In the Makassar Strait, records of reconstructed sea surface salinity and radiocarbon (used to trace water masses) indicate that changes in the mean state of the EAWM and Indo-Pacific climate alter the advection of South China Sea surface waters into the Indonesian Seas. Farther along the ITF pathway, records of reconstructed sea surface salinity from the northern and southern Lombok Strait reveal along-channel shifts in the contribution of South China Sea waters that coincide with the transition from a strong to weak EAWM mean state in the mid-20th century. This multi-site, multi-proxy study thus documents that changes in the strength and state of the EAWM alter surface water circulation throughout the western Indonesian Seas, likely interacting with southward ITF transport and thus regional and global climate systems across the Indo-Pacific.

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Members of the Examination Committee:

  • Associate Professor Nerilie Abrams (External Examiner), Australian National University, Australia
  • Dr Nancy Grumet Prouty (External Examiner), United States Geological Survey, USA
  • Assistant Professor Patrick Martin (Internal Examiner), Nanyang Technological University, Singapore

Oral Examination Committee:

  • Associate Professor Jesvin Yeo Puay Hwa (Chairman), Nanyang Technological University, Singapore
  • Professor Arnold Gordon (Oral Examiner), Columbia University, USA
  • Professor Steve Lansing (Oral Examiner), Nanyang Technological University, Singapore
  • Associate Professor Emma Hill (Oral Examiner), Nanyang Technological University, Singapore     
  • Assistant Professor Patrick Martin (Oral Examiner), Nanyang Technological University, Singapore 

Advisors:

  • Associate Professor Nathalie Goodkin, Nanyang Technological University, Singapore
  • Associate Professor Kimberly Kline, Nanyang Technological University, Singapore

About the Speaker: 

Sujata Murty

Sujata Murty received her B.A. in biology and geology (highest honours) from Oberlin College in 2012. Her undergraduate dissertation focused on reconstructing centennial-scale climate variability from sea surface temperature gradients in Red Sea corals. Sujata received fellowships in 2010 and 2011 to conduct research at the Woods Hole Oceanographic Institution, and in 2017 received a fellowship from the Committee on Space Research to conduct interdisciplinary research at the Lamont-Doherty Earth Observatory. She worked as a research assistant with the Goodkin lab at the Earth Observatory of Singapore from 2012 to 2013 before joining the Interdisciplinary Graduate School at Nanyang Technological University as a PhD student under the supervision of Dr Nathalie Goodkin. During her PhD, she used geochemical records from Southeast Asian corals to reconstruct past changes in surface ocean circulation, precipitation and Indo-Pacific climate.

20 Aug 2018
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