Boron isotopes as a proxy for pH in siliceous and calcareous marine algae
Rising CO2 in the atmosphere has directly led to a reduction in surface ocean pH -a process known as ocean acidification. There is a need to understand past climates in terms of ocean pH change in order to be able to relate these to the current effects of climate change on marine organisms. One way of...
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ftsouthampton:oai:eprints.soton.ac.uk:416836 2023-07-30T04:07:04+02:00 Boron isotopes as a proxy for pH in siliceous and calcareous marine algae Donald, Hannah, Katie 2017-11-20 text https://eprints.soton.ac.uk/416836/ https://eprints.soton.ac.uk/416836/1/Donald_Hannah_PhD_Thesis_Nov_17.pdf en English eng University of Southampton https://eprints.soton.ac.uk/416836/1/Donald_Hannah_PhD_Thesis_Nov_17.pdf Donald, Hannah, Katie (2017) Boron isotopes as a proxy for pH in siliceous and calcareous marine algae. University of Southampton, Doctoral Thesis, 178pp. uos_thesis Thesis NonPeerReviewed 2017 ftsouthampton 2023-07-09T22:19:46Z Rising CO2 in the atmosphere has directly led to a reduction in surface ocean pH -a process known as ocean acidification. There is a need to understand past climates in terms of ocean pH change in order to be able to relate these to the current effects of climate change on marine organisms. One way of doing this is by measuring boron isotopes in marine carbonates, such as foraminifera and corals, to estimate past ocean pH, and thus to infer past pCO2. Key regions of atmospheric-ocean CO2 exchange are the Southern Ocean and subarctic North Pacific, and they are also areas where modern ocean acidification is occurring fastest. The current application of the boron isotope proxy is restricted in these high latitude regions due to lack of calcareous organisms preserved in the sediment here. Therefore, there is a need to expand the boron isotope proxy into novel materials, such as diatoms and coralline algae, which are found in these key high latitude habitats in abundance. This thesis aims to investigate whether the hard parts of marine algae (siliceous: di-atoms; calcareous: coralline algae) are suitable archives for the boron isotope pH proxy. This is achieved by examining: (i) which boron species could be incorporated into the frustule/skeleton; (ii) the relationship between boron isotopic composition and seawater pH, and hence the sensitivity of boron isotopes in each organism to changes in seawater pH; (iii) the palaeo-archive potential of each organism. These aims are addressed by developing a method to measure boron isotopes and boron content of diatoms by MC-ICP-MS, calibrating the boron-pH relationships in a species of diatom using culturing experiments, applying this calibration to sedimentary diatoms collected from a core in the subarctic North Pacific, and also by investigating the relationship between boron isotopes and seawater pH in a species of coralline algae. Thesis Southern Ocean Subarctic University of Southampton: e-Prints Soton Southern Ocean |
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University of Southampton: e-Prints Soton |
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language |
English |
description |
Rising CO2 in the atmosphere has directly led to a reduction in surface ocean pH -a process known as ocean acidification. There is a need to understand past climates in terms of ocean pH change in order to be able to relate these to the current effects of climate change on marine organisms. One way of doing this is by measuring boron isotopes in marine carbonates, such as foraminifera and corals, to estimate past ocean pH, and thus to infer past pCO2. Key regions of atmospheric-ocean CO2 exchange are the Southern Ocean and subarctic North Pacific, and they are also areas where modern ocean acidification is occurring fastest. The current application of the boron isotope proxy is restricted in these high latitude regions due to lack of calcareous organisms preserved in the sediment here. Therefore, there is a need to expand the boron isotope proxy into novel materials, such as diatoms and coralline algae, which are found in these key high latitude habitats in abundance. This thesis aims to investigate whether the hard parts of marine algae (siliceous: di-atoms; calcareous: coralline algae) are suitable archives for the boron isotope pH proxy. This is achieved by examining: (i) which boron species could be incorporated into the frustule/skeleton; (ii) the relationship between boron isotopic composition and seawater pH, and hence the sensitivity of boron isotopes in each organism to changes in seawater pH; (iii) the palaeo-archive potential of each organism. These aims are addressed by developing a method to measure boron isotopes and boron content of diatoms by MC-ICP-MS, calibrating the boron-pH relationships in a species of diatom using culturing experiments, applying this calibration to sedimentary diatoms collected from a core in the subarctic North Pacific, and also by investigating the relationship between boron isotopes and seawater pH in a species of coralline algae. |
format |
Thesis |
author |
Donald, Hannah, Katie |
spellingShingle |
Donald, Hannah, Katie Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
author_facet |
Donald, Hannah, Katie |
author_sort |
Donald, Hannah, Katie |
title |
Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
title_short |
Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
title_full |
Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
title_fullStr |
Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
title_full_unstemmed |
Boron isotopes as a proxy for pH in siliceous and calcareous marine algae |
title_sort |
boron isotopes as a proxy for ph in siliceous and calcareous marine algae |
publisher |
University of Southampton |
publishDate |
2017 |
url |
https://eprints.soton.ac.uk/416836/ https://eprints.soton.ac.uk/416836/1/Donald_Hannah_PhD_Thesis_Nov_17.pdf |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean Subarctic |
genre_facet |
Southern Ocean Subarctic |
op_relation |
https://eprints.soton.ac.uk/416836/1/Donald_Hannah_PhD_Thesis_Nov_17.pdf Donald, Hannah, Katie (2017) Boron isotopes as a proxy for pH in siliceous and calcareous marine algae. University of Southampton, Doctoral Thesis, 178pp. |
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uos_thesis |
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1772820161103921152 |