<i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2
Abrupt millennial-scale climate change events of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas) were accompanied by marked increases in atmospheric CO<sub>2</sub> (CO<sub>2atm</sub>) and decreases in its stable carbon isotopic ratios (<i>δ</i&g...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2017-04-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/13/345/2017/cp-13-345-2017.pdf |
| _version_ | 1811294077518348288 |
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| author | M. C. Campos C. M. Chiessi I. Voigt A. R. Piola H. Kuhnert S. Mulitza |
| author_facet | M. C. Campos C. M. Chiessi I. Voigt A. R. Piola H. Kuhnert S. Mulitza |
| author_sort | M. C. Campos |
| collection | DOAJ |
| description | Abrupt millennial-scale climate change events
of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas)
were accompanied by marked increases in atmospheric CO<sub>2</sub> (CO<sub>2atm</sub>)
and decreases in its stable carbon isotopic ratios (<i>δ</i><sup>13</sup>C),
i.e. <i>δ</i><sup>13</sup>CO<sub>2atm</sub>, presumably due to outgassing from the
ocean. However, information on the preceding Heinrich Stadials during the
last glacial period is scarce. Here we present <i>δ</i><sup>13</sup>C records
from two species of planktonic foraminifera from the western South Atlantic
that reveal major decreases (up to 1 ‰) during Heinrich
Stadials 3 and 2. These <i>δ</i><sup>13</sup>C decreases are most likely related
to millennial-scale periods of weakening of the Atlantic
meridional overturning circulation and the consequent increase (decrease) in
CO<sub>2atm</sub> (<i>δ</i><sup>13</sup>CO<sub>2atm</sub>). We hypothesise two mechanisms
that could account for the decreases observed in our records, namely
strengthening of Southern Ocean deep-water ventilation and weakening of the
biological pump. Additionally, we suggest that air–sea gas
exchange could have contributed to the observed <i>δ</i><sup>13</sup>C decreases.
Together with other lines of evidence, our data are consistent with the
hypothesis that the CO<sub>2</sub> added to the atmosphere during abrupt
millennial-scale climate change events of the last glacial period
also originated in the ocean and reached the atmosphere by outgassing. The
temporal evolution of <i>δ</i><sup>13</sup>C during Heinrich Stadials 3 and 2 in
our records is characterized by two relative minima separated by a relative
maximum. This <q>w structure</q> is also found in North Atlantic and
South American records, further suggesting that such a structure is a
pervasive feature of Heinrich Stadial 2 and, possibly, also Heinrich Stadial 3. |
| first_indexed | 2024-04-13T05:11:05Z |
| format | Article |
| id | doaj.art-8f16a480067d45b5aea904a29c10da01 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-04-13T05:11:05Z |
| publishDate | 2017-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-8f16a480067d45b5aea904a29c10da012022-12-22T03:01:01ZengCopernicus PublicationsClimate of the Past1814-93241814-93322017-04-0113434535810.5194/cp-13-345-2017<i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2M. C. Campos0C. M. Chiessi1I. Voigt2A. R. Piola3H. Kuhnert4S. Mulitza5School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, 03828-000, BrazilSchool of Arts, Sciences and Humanities, University of São Paulo, São Paulo, 03828-000, BrazilMARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, GermanyServicio de Hidrografia Naval (SHN), Buenos Aires, C1270ABV, ArgentinaMARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, GermanyMARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, GermanyAbrupt millennial-scale climate change events of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas) were accompanied by marked increases in atmospheric CO<sub>2</sub> (CO<sub>2atm</sub>) and decreases in its stable carbon isotopic ratios (<i>δ</i><sup>13</sup>C), i.e. <i>δ</i><sup>13</sup>CO<sub>2atm</sub>, presumably due to outgassing from the ocean. However, information on the preceding Heinrich Stadials during the last glacial period is scarce. Here we present <i>δ</i><sup>13</sup>C records from two species of planktonic foraminifera from the western South Atlantic that reveal major decreases (up to 1 ‰) during Heinrich Stadials 3 and 2. These <i>δ</i><sup>13</sup>C decreases are most likely related to millennial-scale periods of weakening of the Atlantic meridional overturning circulation and the consequent increase (decrease) in CO<sub>2atm</sub> (<i>δ</i><sup>13</sup>CO<sub>2atm</sub>). We hypothesise two mechanisms that could account for the decreases observed in our records, namely strengthening of Southern Ocean deep-water ventilation and weakening of the biological pump. Additionally, we suggest that air–sea gas exchange could have contributed to the observed <i>δ</i><sup>13</sup>C decreases. Together with other lines of evidence, our data are consistent with the hypothesis that the CO<sub>2</sub> added to the atmosphere during abrupt millennial-scale climate change events of the last glacial period also originated in the ocean and reached the atmosphere by outgassing. The temporal evolution of <i>δ</i><sup>13</sup>C during Heinrich Stadials 3 and 2 in our records is characterized by two relative minima separated by a relative maximum. This <q>w structure</q> is also found in North Atlantic and South American records, further suggesting that such a structure is a pervasive feature of Heinrich Stadial 2 and, possibly, also Heinrich Stadial 3.http://www.clim-past.net/13/345/2017/cp-13-345-2017.pdf |
| spellingShingle | M. C. Campos C. M. Chiessi I. Voigt A. R. Piola H. Kuhnert S. Mulitza <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 Climate of the Past |
| title | <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 |
| title_full | <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 |
| title_fullStr | <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 |
| title_full_unstemmed | <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 |
| title_short | <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2 |
| title_sort | i δ i sup 13 sup c decreases in the upper western south atlantic during heinrich stadials 3 and 2 |
| url | http://www.clim-past.net/13/345/2017/cp-13-345-2017.pdf |
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