Past and future adaptations of phytoplankton to carbon dioxide
Photosynthesis is responsible for fixing approximately 111 – 117 Pg of CO₂ into organic carbon each year, of which about half is performed by algae in the oceans. Over geological timescales, photosynthesis by algae was instrumental in transforming Earth’s atmosphere. Despite the integral role algae...
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| Materiálatiipa: | Oahppočájánas |
| Giella: | English |
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2011
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| Fáttát: |
| _version_ | 1826303915112529920 |
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| author | Young, J Jodi Nicole Young |
| author2 | Rickaby, R |
| author_facet | Rickaby, R Young, J Jodi Nicole Young |
| author_sort | Young, J |
| collection | OXFORD |
| description | Photosynthesis is responsible for fixing approximately 111 – 117 Pg of CO₂ into organic carbon each year, of which about half is performed by algae in the oceans. Over geological timescales, photosynthesis by algae was instrumental in transforming Earth’s atmosphere. Despite the integral role algae play in the carbon cycle, the interaction and feedbacks between CO₂ fixation by algae and atmospheric CO₂ is poorly understood. This thesis expands upon our current knowledge by tracing the evolution of the key enzyme of photosynthesis, Rubisco, in algae through geological history. It was found that Rubisco underwent adaptation during distinct periods corresponding with falling atmospheric CO₂. The pattern of adaptation hints at physiological adaptation to varying concentrations of atmospheric CO2 and possibly indicates the emergence of carbon concentrating mechanisms (CCMs). This adaptation was probed further within the red and chromist algae, identifying key residues within the Rubisco protein sequence that may influence its kinetic properties. This research also provided new measurements of Rubisco CO2 affinity within the haptophyte algae. Finally, the importance of HCO₃- use by phytoplankton in the modern ocean was explored. HCO₃- utilisation was modelled through signals retained within stable carbon isotopes of organic matter estimate the response to anthropogenic increases of CO₂. The results indicate that phytoplankton utilise a large proportion HCO₃- which shows little sensitivity to anthropogenic increases of CO₂, even when model predictions are extended to 2100. This thesis demonstrates how algae can respond to CO₂ levels over geological and anthropogenic time scales. |
| first_indexed | 2024-03-07T06:09:56Z |
| format | Thesis |
| id | oxford-uuid:ef1fc31a-d2a5-4ec4-8849-ea73a74b643b |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:09:56Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:ef1fc31a-d2a5-4ec4-8849-ea73a74b643b2022-03-27T11:38:04ZPast and future adaptations of phytoplankton to carbon dioxideThesishttp://purl.org/coar/resource_type/c_db06uuid:ef1fc31a-d2a5-4ec4-8849-ea73a74b643bEarth sciencesEvolution,ecology and systematicsEnvironmental changeEnglishOxford University Research Archive - Valet2011Young, JJodi Nicole YoungRickaby, RPhotosynthesis is responsible for fixing approximately 111 – 117 Pg of CO₂ into organic carbon each year, of which about half is performed by algae in the oceans. Over geological timescales, photosynthesis by algae was instrumental in transforming Earth’s atmosphere. Despite the integral role algae play in the carbon cycle, the interaction and feedbacks between CO₂ fixation by algae and atmospheric CO₂ is poorly understood. This thesis expands upon our current knowledge by tracing the evolution of the key enzyme of photosynthesis, Rubisco, in algae through geological history. It was found that Rubisco underwent adaptation during distinct periods corresponding with falling atmospheric CO₂. The pattern of adaptation hints at physiological adaptation to varying concentrations of atmospheric CO2 and possibly indicates the emergence of carbon concentrating mechanisms (CCMs). This adaptation was probed further within the red and chromist algae, identifying key residues within the Rubisco protein sequence that may influence its kinetic properties. This research also provided new measurements of Rubisco CO2 affinity within the haptophyte algae. Finally, the importance of HCO₃- use by phytoplankton in the modern ocean was explored. HCO₃- utilisation was modelled through signals retained within stable carbon isotopes of organic matter estimate the response to anthropogenic increases of CO₂. The results indicate that phytoplankton utilise a large proportion HCO₃- which shows little sensitivity to anthropogenic increases of CO₂, even when model predictions are extended to 2100. This thesis demonstrates how algae can respond to CO₂ levels over geological and anthropogenic time scales. |
| spellingShingle | Earth sciences Evolution,ecology and systematics Environmental change Young, J Jodi Nicole Young Past and future adaptations of phytoplankton to carbon dioxide |
| title | Past and future adaptations of phytoplankton to carbon dioxide |
| title_full | Past and future adaptations of phytoplankton to carbon dioxide |
| title_fullStr | Past and future adaptations of phytoplankton to carbon dioxide |
| title_full_unstemmed | Past and future adaptations of phytoplankton to carbon dioxide |
| title_short | Past and future adaptations of phytoplankton to carbon dioxide |
| title_sort | past and future adaptations of phytoplankton to carbon dioxide |
| topic | Earth sciences Evolution,ecology and systematics Environmental change |
| work_keys_str_mv | AT youngj pastandfutureadaptationsofphytoplanktontocarbondioxide AT jodinicoleyoung pastandfutureadaptationsofphytoplanktontocarbondioxide |