Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae
The present work examines the relationship between pH-induced changes in growth and stable isotopic composition of coccolith calcite in two coccolithophore species with a geological perspective. These species (Gephyrocapsa oceanica and Coccolithus pelagicus) with differing physiologies and vital eff...
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| Format: | Journal article |
| Language: | English |
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American Geophysical Union
2015
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| _version_ | 1797062549239234560 |
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| author | Hermoso, M |
| author_facet | Hermoso, M |
| author_sort | Hermoso, M |
| collection | OXFORD |
| description | The present work examines the relationship between pH-induced changes in growth and stable isotopic composition of coccolith calcite in two coccolithophore species with a geological perspective. These species (Gephyrocapsa oceanica and Coccolithus pelagicus) with differing physiologies and vital effects possess a growth optimum corresponding to average pH of surface seawater in the geological period during their first known occurrence. The “ancestral” C. pelagicus has much wider pH tolerance in terms of growth rates than the more recently evolved G. oceanica. Diminished growth rates are explained by the challenge of proton translocation into the extracellular environment at low pH and enhanced aqueous CO2 limitation at high pH. Reducing the cell dynamics in this way leads to a lower degree of oxygen isotopic disequilibrium in G. oceanica. In contrast, the slower growing species C. pelagicus, which typically precipitates near-equilibrium calcite, does not show any modulation of oxygen isotope signals with changing pH. Overall, carbon and oxygen isotope compositions are best explained by the degree of utilization of the internal dissolved inorganic carbon (DIC) pool and the dynamics of isotopic reequilibration inside the cell. Thus, the “carbonate ion effect” may not apply to coccolithophores. This difference with foraminifera can be traced to different modes of DIC incorporation into these two distinct biomineralizing organisms. From a geological perspective, these findings have implications for refining the use of oxygen isotopes to infer more reliable sea surface temperatures (SSTs) from fossil carbonates and contribute to a better understanding of how climate-relevant parameters are recorded in the sedimentary archive. |
| first_indexed | 2024-03-06T20:47:06Z |
| format | Journal article |
| id | oxford-uuid:3646f2f3-9087-4469-8027-45de4f3ecb41 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T20:47:06Z |
| publishDate | 2015 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:3646f2f3-9087-4469-8027-45de4f3ecb412022-03-26T13:36:53ZControl of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algaeJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:3646f2f3-9087-4469-8027-45de4f3ecb41PaleoceanographyEnglishORA DepositAmerican Geophysical Union2015Hermoso, MThe present work examines the relationship between pH-induced changes in growth and stable isotopic composition of coccolith calcite in two coccolithophore species with a geological perspective. These species (Gephyrocapsa oceanica and Coccolithus pelagicus) with differing physiologies and vital effects possess a growth optimum corresponding to average pH of surface seawater in the geological period during their first known occurrence. The “ancestral” C. pelagicus has much wider pH tolerance in terms of growth rates than the more recently evolved G. oceanica. Diminished growth rates are explained by the challenge of proton translocation into the extracellular environment at low pH and enhanced aqueous CO2 limitation at high pH. Reducing the cell dynamics in this way leads to a lower degree of oxygen isotopic disequilibrium in G. oceanica. In contrast, the slower growing species C. pelagicus, which typically precipitates near-equilibrium calcite, does not show any modulation of oxygen isotope signals with changing pH. Overall, carbon and oxygen isotope compositions are best explained by the degree of utilization of the internal dissolved inorganic carbon (DIC) pool and the dynamics of isotopic reequilibration inside the cell. Thus, the “carbonate ion effect” may not apply to coccolithophores. This difference with foraminifera can be traced to different modes of DIC incorporation into these two distinct biomineralizing organisms. From a geological perspective, these findings have implications for refining the use of oxygen isotopes to infer more reliable sea surface temperatures (SSTs) from fossil carbonates and contribute to a better understanding of how climate-relevant parameters are recorded in the sedimentary archive. |
| spellingShingle | Paleoceanography Hermoso, M Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title | Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title_full | Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title_fullStr | Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title_full_unstemmed | Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title_short | Control of ambient pH on growth and stable isotopes in phytoplanktonic calcifying algae |
| title_sort | control of ambient ph on growth and stable isotopes in phytoplanktonic calcifying algae |
| topic | Paleoceanography |
| work_keys_str_mv | AT hermosom controlofambientphongrowthandstableisotopesinphytoplanktoniccalcifyingalgae |