Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment

Anthropogenic emissions of carbon dioxide (CO2) into the atmosphere results in climate change and perturbations of the oceanic carbonate system. Atmospheric CO2 concentrations have increased from pre-industrial times from land use changes, fossil fuel combustion and increasing cement production. The...

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Main Author: Clarke, Jennifer
Format: Thesis
Language:English
Published: 2015
Subjects:
Online Access:https://eprints.soton.ac.uk/384569/
https://eprints.soton.ac.uk/384569/1/Clarke%252C%2520Jennifer_Nov_PhD.pdf
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spelling ftsouthampton:oai:eprints.soton.ac.uk:384569 2023-07-30T04:05:37+02:00 Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment Clarke, Jennifer 2015-11-16 text https://eprints.soton.ac.uk/384569/ https://eprints.soton.ac.uk/384569/1/Clarke%252C%2520Jennifer_Nov_PhD.pdf en English eng https://eprints.soton.ac.uk/384569/1/Clarke%252C%2520Jennifer_Nov_PhD.pdf Clarke, Jennifer (2015) Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment. University of Southampton, Ocean & Earth Science, Doctoral Thesis, 171pp. Thesis NonPeerReviewed 2015 ftsouthampton 2023-07-09T22:03:10Z Anthropogenic emissions of carbon dioxide (CO2) into the atmosphere results in climate change and perturbations of the oceanic carbonate system. Atmospheric CO2 concentrations have increased from pre-industrial times from land use changes, fossil fuel combustion and increasing cement production. The ocean is currently a major sink for this anthropogenic CO2, increasing pCO2 and dissolved inorganic carbon concentrations and decreasing pH and carbonate ion concentrations. This has potential biogeochemical and ecosystem consequences. To monitor the ocean’s uptake of CO2, identify regions of enhanced carbonate system changes, and observe the effectiveness of CO2 emission mitigation strategies, high quality pCO2 and pH measurements with good temporal and spatial coverage are required. This thesis presents the characterisation of novel pH and pCO2 sensing spots which use fluorescent detection techniques, and evaluates their potential for in situ seawater deployments. The optode sensing spots were illuminated with low intensity light (0.2 mA, 0.72 mWatt), and the time-domain dual lifetime referencing analysis technique was applied to maximise the lifetime of the spot and reduce overall power consumption of the measurement (1.8 Watt). The same hardware was used for both the pH and pCO2 spot interrogation, thereby demonstrating the versatility of the optode. After initial calibrations over typical seawater ranges for pH and pCO2, (pH range 7.6 – 8.2 and pCO2 range 280-1000 ?atm) the temperature and salinity dependence of the spots was evaluated. The pH displayed both a temperature (- 0.046 pH / °C from 5-25 °C) and salinity dependency (-0.01 pH /psu over 5-35), while the pCO2 sensor showed only a temperature dependence (-39 ?atm °C-1). Precision of the repeated measurement of certified reference material was 0.0074 pH and 0.8 ?atm for the pH and pCO2 optodes, respectively. The optodes were deployed as shipboard autonomous underway systems in the North Atlantic and Southern Ocean, both important CO2 sink regions. The ... Thesis North Atlantic Southern Ocean University of Southampton: e-Prints Soton Southern Ocean
institution Open Polar
collection University of Southampton: e-Prints Soton
op_collection_id ftsouthampton
language English
description Anthropogenic emissions of carbon dioxide (CO2) into the atmosphere results in climate change and perturbations of the oceanic carbonate system. Atmospheric CO2 concentrations have increased from pre-industrial times from land use changes, fossil fuel combustion and increasing cement production. The ocean is currently a major sink for this anthropogenic CO2, increasing pCO2 and dissolved inorganic carbon concentrations and decreasing pH and carbonate ion concentrations. This has potential biogeochemical and ecosystem consequences. To monitor the ocean’s uptake of CO2, identify regions of enhanced carbonate system changes, and observe the effectiveness of CO2 emission mitigation strategies, high quality pCO2 and pH measurements with good temporal and spatial coverage are required. This thesis presents the characterisation of novel pH and pCO2 sensing spots which use fluorescent detection techniques, and evaluates their potential for in situ seawater deployments. The optode sensing spots were illuminated with low intensity light (0.2 mA, 0.72 mWatt), and the time-domain dual lifetime referencing analysis technique was applied to maximise the lifetime of the spot and reduce overall power consumption of the measurement (1.8 Watt). The same hardware was used for both the pH and pCO2 spot interrogation, thereby demonstrating the versatility of the optode. After initial calibrations over typical seawater ranges for pH and pCO2, (pH range 7.6 – 8.2 and pCO2 range 280-1000 ?atm) the temperature and salinity dependence of the spots was evaluated. The pH displayed both a temperature (- 0.046 pH / °C from 5-25 °C) and salinity dependency (-0.01 pH /psu over 5-35), while the pCO2 sensor showed only a temperature dependence (-39 ?atm °C-1). Precision of the repeated measurement of certified reference material was 0.0074 pH and 0.8 ?atm for the pH and pCO2 optodes, respectively. The optodes were deployed as shipboard autonomous underway systems in the North Atlantic and Southern Ocean, both important CO2 sink regions. The ...
format Thesis
author Clarke, Jennifer
spellingShingle Clarke, Jennifer
Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
author_facet Clarke, Jennifer
author_sort Clarke, Jennifer
title Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
title_short Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
title_full Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
title_fullStr Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
title_full_unstemmed Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment
title_sort characterisation of ph and pco2 optodes towards high resolution in situ ocean deployment
publishDate 2015
url https://eprints.soton.ac.uk/384569/
https://eprints.soton.ac.uk/384569/1/Clarke%252C%2520Jennifer_Nov_PhD.pdf
geographic Southern Ocean
geographic_facet Southern Ocean
genre North Atlantic
Southern Ocean
genre_facet North Atlantic
Southern Ocean
op_relation https://eprints.soton.ac.uk/384569/1/Clarke%252C%2520Jennifer_Nov_PhD.pdf
Clarke, Jennifer (2015) Characterisation of pH and pCO2 optodes towards high resolution in situ ocean deployment. University of Southampton, Ocean & Earth Science, Doctoral Thesis, 171pp.
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