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Dr Sunitha Pangala

Profile summary

  • Visiting Informal Academic
  • Visiting Fellow
  • Faculty of Science, Technology, Engineering & Mathematics
  • School of Environment, Earth & Ecosystem Sciences
  • sunitha.pangala

Professional biography

I investigate the capacity for tropical trees to emit soil-produced methane to the atmosphere. My work focusses on two unique ecosystems: Bornean peatswamp forests and Amazonian wetlands. I not only assess if this understudied methane transport pathway can make sizeable contributions to regional and global methane budgets but also investigate the mechanisms responsible for methane transport in trees and insights on controls and variability.   

I am now a recipient of the Royal Society Dorothy Hodgkin Research Fellowship (2017-2022) and have moved to Lancaster Environment Centre, Lancaster University. My new email address is s.pangala@lancaster.ac.uk.

Education:

PhD in Earth and Environmental Sciences  (2009 - 2013)

The Open University, Milton Keynes.

Research Project: “Methane emissions from wetland trees: controls and variability”

PhD Supervisors: Dr. Vincent Gauci, Prof. David Gowing & Dr. Edward Hornibrook

My PhD project investigated the role of wetland adapted trees in transporting soil-produced methane to the atmosphere from both tropical and temperate forested wetlands.  The study suggests that trees in tropical and temperate wetlands emit significant quantities of methane, contributing up to 89% to the ecosystem methane flux. Given that, methane is an important greenhouse gas and 60% of the global wetlands are forested, our study underscores the need for the inclusion of methane emissions from trees in global methane budget estimates, in order to accurately predict its responses to changing environment.

MSc by Research in Environmental Geosciences  (2007 – 2008)

School of Geosciences, University of Edinburgh, Edinburgh, UK

Research Project: “Mitigation of methane emissions from a constructed wetland”

Supervisors: Dr. Dave Reay & Dr. Kate Heal (School of Geosciences)

My Master's project explored the potential for mitigating methane emissions from constructed wetland using two electron acceptors (ochre, a by-product generated from acid mine drain treatment and gypsum), whilst maintaining their water treatment efficiency. Under in-situ conditions, gypsum did not supress methane emissions but the use of ochre (a waste product which is often landfilled) offered a win-win situation by suppressed methane emissions by upto 70% without altering the water treatment efficiency of the wetland.

Bachelor of Engineering in Environmental Engineering (4 years, Hons)    (2000 – 2004)

Visveswaraiah Technological University, Mysore, India

Final Year Research Project: “Polluted ground water treatment using low cost indigenous media”

 

Research interests

Biogeochemical cycling of carbon and nitrogen in forested ecosystems, global change and their impacts on carbon and nitrogen cycling, global methane budget, carbon cycling in peatlands and mangroves, microbial ecology, methane cycling within trees, pathways of methane emissions, microbial interactions in soil, tree physiology and forest ecology. 

Research Activity

Externally funded projects

The role of wetland trees in atmospheric methane emissions: do wetland trees drive the production, consumption and emission of methane?

RoleStart dateEnd dateFunding source
Lead01/Dec/201730/Nov/2022The Royal Society
Methane emissions from wetland trees are an overlooked source of atmospheric methane (CH4; a powerful greenhouse gas) with poor resolution of their global significance and mechanisms. My recent pioneering study in the Amazonian floodplains demonstrates that wetland-adapted trees emit half of all the CH4 emitted from the Amazon basin. This important contribution to the regional CH4 budget (equivalent to the entire Arctic CH4 emissions) helps reconcile the ‘top down’ ‘bottom-up’ CH4 discrepancy that exists for Amazon CH4 budget. This study revealed the importance of tree CH4 emissions globally while highlighting our limited knowledge of the mechanisms driving these emissions and the factors controlling their variability. I hypothesise that trees act as bioreactors wherein most CH4 cycling occurs within the trees and their root zones while the adjacent soil system plays only a subsidiary role. Such a finding could transform our understanding of CH4 dynamics in forested wetlands. To this end, controlled water-table mesocosm experiments and in situ investigations in a temperate forested wetland will be used to elucidate the underpinning processes of CH4 cycling. Stable carbon isotopes (δ13C) measured from all CH4 emitting pathways and CH4 in the soil, will be used to establish the very first character and range of δ13C values of CH4 flux from trees in forested wetlands. Novel experiments using 13C-labelled CH4, acetate and CO2 will be carried out in the mesocosms and in situ to identify how photosynthetically fixed carbon is transformed by in-tree and rhizospheric processes. My study will therefore lay the foundation for a holistic understanding of CH4 cycling in forested wetlands which will help process-based models to accurately represent changes in wetland CH4 emissions.

Publications

Large emissions from floodplain trees close the Amazon methane budget (2017-12-14)
Pangala, Sunitha R.; Enrich-Prast, Alex; Basso, Luana S.; Bittencourt Peixoto, Roberta; Bastviken, David; Hornibrook, Edward R. C.; Gatti, Luciana V.; Moratta, Humberto; Calazans, Luana Silva Braucks; Sakuragui, Cassia Mônica; Bastos, Wanderley Rodrigues; Malm, Olaf; Gloor, Emanuel; Miller, John Bharat and Gauci, Vincent
Nature, 552 (pp. 230-234)
Semi-rigid chambers for methane gas flux measurements on tree stems (2016-02-26)
Siegenthaler, Andy; Welch, Bertie; Pangala, Sunitha R.; Peacock, Michael and Gauci, Vincent
Biogeosciences, 13 (pp. 1197-1207)
The contribution of trees to ecosystem methane emissions in a temperate forested wetland (2015-07)
Pangala, Sunitha R.; Hornibrook, Edward R.C.; Gowing, David J. and Gauci, Vincent
Global Change Biology, 21(7) (pp. 2642-2654)
Controls on methane emissions from Alnus glutinosa saplings (2014-02)
Pangala, Sunitha R.; Gowing, David J.; Hornibrook, Edward R. C. and Gauci, Vincent
New Phytologist, 201(3) (pp. 887-896)
Trees are major conduits for methane egress from tropical forested wetlands (2013)
Pangala, Sunitha R.; Moore, Sam; Hornibrook, Edward R. C. and Gauci, Vincent
New Phytologist, 197(2) (pp. 524-531)
Mitigation of methane emissions from constructed farm wetlands (2010-01)
Pangala, Sunitha R.; Reay, David S. and Heal, Kate V.
Chemosphere, 78(5) (pp. 493-499)
Methane production and transport in a tropical peatland (2014)
Hoyt, Alison; Pangala, Sunitha; Gandois, Laure; Cobb, Alex; Kai, Fuu-Ming; Xu, Xiaomei; Gauci, Vincent; Mahmud, Y.; Kamariah, A.; Eri, Jangarun and Harvey, Charles
In : AGU Fall Meeting (15-19 Dec 2014, San Francisco, CA, USA)
Methane emissions from woody stems of tropical and temperate wetland trees (2013-12-12)
Pangala, S. R.; Hornibrook, E. R.; Gowing, D. J.; Bastviken, D.; Enrich-Prast, A. and Gauci, V.
In : AGU Fall Meeting (9-13 Dec 2010, San Francisco, CA, USA)
Trees are important conduits for emission of methane from temperate and tropical wetlands (2013-04)
Gauci, Vincent; Pangala, Sunitha; Gowing, David and Hornibrook, Edward
In : European Geosciences Union General Assembly (07-12 Apr 2013, Vienna)
Methane emission through trees in temperate and tropical wetlands (2012-12)
Pangala, Sunitha R.; Gauci, Vincent; Hornibrook, Edward R. C. and Gowing, David
In : AGU Fall Meeting (3-7 Dec 2012, San Francisco, CA, USA)
Considering scale when assessing wetland methane emissions: wetland forest soils versus wetland forests (2012-06)
Gauci, Vincent and Pangala, Sunitha R.
In : 9th INTECOL International Wetlands Conference: Wetlands In A Complex World (03-08 Jun 2012, Orlando, Florida) (p 156)
Methane emissions through trees in tropical and temperate forested wetlands (2012-06)
Pangala, Sunitha R.; Gauci, Vincent; Hornibrook, Edward R. C. and Gowing, David J.
In : 9th INTECOL International Wetlands Conference: Wetlands in a Complex World (03-08 Jun 2012, Orlando, Florida) (p 170)
Tree-mediated methane emissions from tropical and temperate peatlands (2012-04-26)
Pangala, S. R.; Gauci, V.; Hornibrook, E. R. C. and Gowing, D. J.
In : EGU General Assembly 2012 (22-27 Apr 2012, Vienna)