Sarah Cook

2016 AFPGR Participant


Organic carbon losses in waters draining peatland oil palm plantations in South East Asia

About Sarah

Sarah Cook is a research student working towards completion of her doctoral degree in the Department of Geography. Sarah is supervised by Professor Sue Page and Dr Mick Whelan.

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About My Research

Intact tropical peatlands are valuable stores of carbon; their high water-tables promote the presence of waterlogged conditions, which prevents organic matter being degrading and thus, carbon is stored within their structure.  The largest resource of tropical peat is found within Southeast Asia, particularly Indonesia and Malaysia which contribute the majority share. However, these ecosystems are often exploited for economic benefit and converted into other forms of land-use. One such example is the conversion of tropical peatlands into oil palm plantations, which is common throughout Southeast Asia. In order to convert tropical peatlands into industrial plantations significant land modifications are required, mainly deforestation and drainage, in order to clear the existing forest and lower the high water-table, enabling agricultural practises to be supported. Oil palm requires specific water-table depths to support its production, thus, continuous drainage is required to maintain a low water table. This is facilitated through the establishment of a complex grid of interconnecting drainage channels which flush out any excess water.

These land modifications lead to significant perturbations in the peat’s carbon reservoirs leading to the release of stored carbon into the atmosphere, significantly contributing the greenhouse gas emissions, converting these carbon sinks into carbon sources. Dependable carbon loss estimates from oil palm plantations on tropical peat are few. Research has heavily focused on the direct gaseous carbon emissions released during this conversion processes and has largely excluded the indirect carbon losses occurring in the drainage waters.

At present, this aquatic component remains largely overlooked but could represent a potentially hidden and important contributor to peatland plantation greenhouse gas emissions. The aim of this research is to address this knowledge gap by monitoring the concentrations of carbon in water draining from two oil palm estates and nearby stands of tropical peat swamp forest in Sarawak, Malaysia, over a 12 month period. The results will be used to help quantify carbon emissions from this land-use change, thereby supporting more sustainable plantation management, as well as potentially helping countries, such as Malaysia, to better monitor, report and verify land-based greenhouse gas emissions. 

Research Findings

The results of this investigation are still on-going. To date I have carried out two intense 12-15 week field campaigns to Malaysia and will be returning again in August 2016. Findings so far suggest that there are differences in the quantity and quality of the organic carbon lost in the waters draining the peatland oil palm plantations and forest land cover-types. However, on-going data collection will enable a fuller picture of the temporal fluvial organic carbon losses to be established. Further work to generate flux data from the study sites will allow for a comparison to be made between the plantation and forest land-cover classes. In addition, it is hoped that radiocarbon dating techniques will be used to determine the ages of the carbon being lost and establish if these carbon loses are modern or aged.     

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