Abstract
Evaluation of foraminiferal test dissolution in deep-sea sediments facilitates reconstruction of seawater chemistry. Here we observed test dissolution processes of the planktic foraminifera Trilobatus sacculifer, Globigerinoides ruber, and Neogloboquadrina dutertrei from midlatitudes of the western North Pacific; in these three species, we tested the ability of a new dissolution index using data from X-ray micro-computed tomography scanning. Although the dissolution process of foraminiferal tests differed slightly among species, dissolution of all species was equally assessed by the calcite density distribution (%Low-CT-number calcite volume) calculated from the CT number histogram. In T. sacculifer and G. ruber, the test area density, a conventional proxy for assessing test condition based on weight measurement, is affected by variations in the thickness of the outermost chamber wall; thus, this conventional proxy can be affected by sea surface conditions during test calcification. In contrast, the relationship between the %Low-CT-number calcite volume of tests and the deep seawater calcite saturation state suggests that X-ray micro-computed tomography scanning is applicable for evaluating the intensity of foraminiferal test dissolution at the undersaturated deep seafloor in this area and is an invaluable proxy for detecting deep seawater carbonate ion concentration changes on glacial-interglacial timescales.
| Original language | English |
|---|---|
| Pages (from-to) | 6051-6065 |
| Number of pages | 15 |
| Journal | Geochemistry, Geophysics, Geosystems |
| Volume | 20 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Dec 1 2019 |
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All Science Journal Classification (ASJC) codes
- Geophysics
- Geochemistry and Petrology
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Micro-CT Scanning of Tests of Three Planktic Foraminiferal Species to Clarify DissolutionProcess and Progress. / Iwasaki, S.; Kimoto, K.; Okazaki, Y.; Ikehara, M.
In: Geochemistry, Geophysics, Geosystems, Vol. 20, No. 12, 01.12.2019, p. 6051-6065.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Micro-CT Scanning of Tests of Three Planktic Foraminiferal Species to Clarify DissolutionProcess and Progress
AU - Iwasaki, S.
AU - Kimoto, K.
AU - Okazaki, Y.
AU - Ikehara, M.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Evaluation of foraminiferal test dissolution in deep-sea sediments facilitates reconstruction of seawater chemistry. Here we observed test dissolution processes of the planktic foraminifera Trilobatus sacculifer, Globigerinoides ruber, and Neogloboquadrina dutertrei from midlatitudes of the western North Pacific; in these three species, we tested the ability of a new dissolution index using data from X-ray micro-computed tomography scanning. Although the dissolution process of foraminiferal tests differed slightly among species, dissolution of all species was equally assessed by the calcite density distribution (%Low-CT-number calcite volume) calculated from the CT number histogram. In T. sacculifer and G. ruber, the test area density, a conventional proxy for assessing test condition based on weight measurement, is affected by variations in the thickness of the outermost chamber wall; thus, this conventional proxy can be affected by sea surface conditions during test calcification. In contrast, the relationship between the %Low-CT-number calcite volume of tests and the deep seawater calcite saturation state suggests that X-ray micro-computed tomography scanning is applicable for evaluating the intensity of foraminiferal test dissolution at the undersaturated deep seafloor in this area and is an invaluable proxy for detecting deep seawater carbonate ion concentration changes on glacial-interglacial timescales.
AB - Evaluation of foraminiferal test dissolution in deep-sea sediments facilitates reconstruction of seawater chemistry. Here we observed test dissolution processes of the planktic foraminifera Trilobatus sacculifer, Globigerinoides ruber, and Neogloboquadrina dutertrei from midlatitudes of the western North Pacific; in these three species, we tested the ability of a new dissolution index using data from X-ray micro-computed tomography scanning. Although the dissolution process of foraminiferal tests differed slightly among species, dissolution of all species was equally assessed by the calcite density distribution (%Low-CT-number calcite volume) calculated from the CT number histogram. In T. sacculifer and G. ruber, the test area density, a conventional proxy for assessing test condition based on weight measurement, is affected by variations in the thickness of the outermost chamber wall; thus, this conventional proxy can be affected by sea surface conditions during test calcification. In contrast, the relationship between the %Low-CT-number calcite volume of tests and the deep seawater calcite saturation state suggests that X-ray micro-computed tomography scanning is applicable for evaluating the intensity of foraminiferal test dissolution at the undersaturated deep seafloor in this area and is an invaluable proxy for detecting deep seawater carbonate ion concentration changes on glacial-interglacial timescales.
UR - http://www.scopus.com/inward/record.url?scp=85076339099&partnerID=8YFLogxK
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U2 - 10.1029/2019GC008456
DO - 10.1029/2019GC008456
M3 - Article
AN - SCOPUS:85076339099
VL - 20
SP - 6051
EP - 6065
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
SN - 1525-2027
IS - 12
ER -