The effect of microbial activity and adsorption processes on groundwater dissolved organic carbon character and concentration
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Date
2017-12-14
Journal Title
Journal ISSN
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Publisher
American Geophysical Union (AGU)
Abstract
Balancing the terrestrial global carbon budget has proven to be a significant challenge. Whilst the movement of carbon in the atmosphere, rivers and oceans has been extensively studied, the potential for groundwater to act as a carbon source or sink through both microbial activity and sorption to and from mineral surfaces, is poorly understood. To investigate the biodegradable component of groundwater dissolved organic carbon (DOC), groundwater samples were collected from multiple coastal and inland sites. Water quality parameters such as pH, electrical conductivity, temperature, dissolved oxygen were measured in the field. Samples were analysed and characterised for their biodegradable DOC content using spectrofluorometric and Liquid Chromatography-Organic Carbon Detection (LC-OCD) techniques at set intervals within a 28 day period. Further to this, we performed laboratory sorption experiments on our groundwater samples using different minerals to examine the effect of adsorption processes on DOC character and concentration. Calcium carbonate, quartz and iron coated quartz were heated to 400ºC to remove potential carbon contamination, and then added at various known masses (0 mg to 10 g) to 50 mL of groundwater. Samples were then rotated for two hours, filtered at 0.2 μm and analysed by LC-OCD. This research forms part of an ongoing project which will assist in identifying the factors affecting the mobilisation, transport and removal of DOC in uncontaminated groundwater. By quantifying the relative importance of these processes, we can then determine whether the groundwater is a carbon source or sink. Importantly, this information will help guide policy and identify the need to include groundwater resources as part of the carbon economy.
Description
Keywords
Ground water, Adsorption, Carbon, Microorganisms, Carbon sinks, Minerals
Citation
McDonough, L., Oudone, P., Rutlidge, H., Meredith, K., O'Carroll, D. M., Andersen, M. S., & Baker, A. (2017). The effect of microbial activity and adsorption processes on groundwater dissolved organic carbon character and concentration. Poster presented at the AGU Fall Meeting, 2017, New Orleans, Louisiana, USA, 11-15 December 2017. In AGU Fall Meeting Abstracts, Vol. 2017, B43F-1621. Retrieved from: https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/219381