Technical note: An empirical method for absolute calibration of coccolith thickness
As major calcifiers in the open ocean, coccolithophores play a key role in the marine carbon cycle. Because they may be sensitive to changing CO 2 and ocean acidification, there is significant interest in quantifying past and present variations in their cellular calcification by quantifying the thic...
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ftcopernicus:oai:publications.copernicus.org:bg59682 2023-05-15T17:51:23+02:00 Technical note: An empirical method for absolute calibration of coccolith thickness González-Lemos, Saúl Guitián, José Fuertes, Miguel-Ángel Flores, José-Abel Stoll, Heather M. 2018-09-27 application/pdf https://doi.org/10.5194/bg-15-1079-2018 https://www.biogeosciences.net/15/1079/2018/ eng eng doi:10.5194/bg-15-1079-2018 https://www.biogeosciences.net/15/1079/2018/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-15-1079-2018 2019-12-24T09:50:37Z As major calcifiers in the open ocean, coccolithophores play a key role in the marine carbon cycle. Because they may be sensitive to changing CO 2 and ocean acidification, there is significant interest in quantifying past and present variations in their cellular calcification by quantifying the thickness of the coccoliths or calcite plates that cover their cells. Polarized light microscopy has emerged as a key tool for quantifying the thickness of these calcite plates, but the reproducibility and accuracy of such determinations has been limited by the absence of suitable calibration materials in the thickness range of coccoliths (0–4 µm). Here, we describe the fabrication of a calcite wedge with a constant slope over this thickness range, and the independent determination of calcite thickness along the wedge profile. We show how the calcite wedge provides more robust calibrations in the 0 to 1.55 µm range than previous approaches using rhabdoliths. We show the particular advantages of the calcite wedge approach for developing equations to relate thickness to the interference colors that arise in calcite in the thickness range between 1.55 and 4 µm. The calcite wedge approach can be applied to develop equations relevant to the particular light spectra and intensity of any polarized light microscope system and could significantly improve inter-laboratory data comparability. Text Ocean acidification Copernicus Publications: E-Journals Biogeosciences 15 4 1079 1091 |
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As major calcifiers in the open ocean, coccolithophores play a key role in the marine carbon cycle. Because they may be sensitive to changing CO 2 and ocean acidification, there is significant interest in quantifying past and present variations in their cellular calcification by quantifying the thickness of the coccoliths or calcite plates that cover their cells. Polarized light microscopy has emerged as a key tool for quantifying the thickness of these calcite plates, but the reproducibility and accuracy of such determinations has been limited by the absence of suitable calibration materials in the thickness range of coccoliths (0–4 µm). Here, we describe the fabrication of a calcite wedge with a constant slope over this thickness range, and the independent determination of calcite thickness along the wedge profile. We show how the calcite wedge provides more robust calibrations in the 0 to 1.55 µm range than previous approaches using rhabdoliths. We show the particular advantages of the calcite wedge approach for developing equations to relate thickness to the interference colors that arise in calcite in the thickness range between 1.55 and 4 µm. The calcite wedge approach can be applied to develop equations relevant to the particular light spectra and intensity of any polarized light microscope system and could significantly improve inter-laboratory data comparability. |
format |
Text |
author |
González-Lemos, Saúl Guitián, José Fuertes, Miguel-Ángel Flores, José-Abel Stoll, Heather M. |
spellingShingle |
González-Lemos, Saúl Guitián, José Fuertes, Miguel-Ángel Flores, José-Abel Stoll, Heather M. Technical note: An empirical method for absolute calibration of coccolith thickness |
author_facet |
González-Lemos, Saúl Guitián, José Fuertes, Miguel-Ángel Flores, José-Abel Stoll, Heather M. |
author_sort |
González-Lemos, Saúl |
title |
Technical note: An empirical method for absolute calibration of coccolith thickness |
title_short |
Technical note: An empirical method for absolute calibration of coccolith thickness |
title_full |
Technical note: An empirical method for absolute calibration of coccolith thickness |
title_fullStr |
Technical note: An empirical method for absolute calibration of coccolith thickness |
title_full_unstemmed |
Technical note: An empirical method for absolute calibration of coccolith thickness |
title_sort |
technical note: an empirical method for absolute calibration of coccolith thickness |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-15-1079-2018 https://www.biogeosciences.net/15/1079/2018/ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-15-1079-2018 https://www.biogeosciences.net/15/1079/2018/ |
op_doi |
https://doi.org/10.5194/bg-15-1079-2018 |
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Biogeosciences |
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15 |
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1091 |
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1766158518842294272 |