Processes determining the marine alkalinity and calcium carbonate saturation state distributions
We introduce a composite tracer for the marine system, Alk<sup>*</sup>, that has a global distribution primarily determined by CaCO<sub>3</sub> precipitation and dissolution. Alk<sup>*</sup> is also affected by riverine alkalinity from dissolved terrestrial carbon...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-12-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/7349/2014/bg-11-7349-2014.pdf |
| _version_ | 1819127409629200384 |
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| author | B. R. Carter J. R. Toggweiler R. M. Key J. L. Sarmiento |
| author_facet | B. R. Carter J. R. Toggweiler R. M. Key J. L. Sarmiento |
| author_sort | B. R. Carter |
| collection | DOAJ |
| description | We introduce a composite tracer for the marine system, Alk<sup>*</sup>, that has a
global distribution primarily determined by CaCO<sub>3</sub> precipitation and
dissolution. Alk<sup>*</sup> is also affected by riverine alkalinity from dissolved
terrestrial carbonate minerals. We estimate that the Arctic receives
approximately twice the riverine alkalinity per unit area as the Atlantic,
and 8 times that of the other oceans. Riverine inputs broadly elevate Alk<sup>*</sup>
in the Arctic surface and particularly near river mouths. Strong net
carbonate precipitation results in low Alk<sup>*</sup> in subtropical gyres,
especially in the Indian and Atlantic oceans. Upwelling of dissolved CaCO<sub>3</sub>-rich deep water elevates North Pacific and
Southern Ocean Alk<sup>*</sup>. We use the Alk<sup>*</sup> distribution to estimate the
variability of the calcite saturation state resulting from CaCO<sub>3</sub> cycling
and other processes. We show that regional differences in surface calcite
saturation state are due primarily to the effect of temperature differences
on CO<sub>2</sub> solubility and, to a lesser extent, differences in freshwater
content and air–sea disequilibria. The variations in net calcium carbonate
cycling revealed by Alk<sup>*</sup> play a comparatively minor role in determining
the calcium carbonate saturation state. |
| first_indexed | 2024-12-22T08:11:28Z |
| format | Article |
| id | doaj.art-66f1e177be934ec99dbb9035a35213b2 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-22T08:11:28Z |
| publishDate | 2014-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-66f1e177be934ec99dbb9035a35213b22022-12-21T18:33:01ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-12-0111247349736210.5194/bg-11-7349-2014Processes determining the marine alkalinity and calcium carbonate saturation state distributionsB. R. Carter0J. R. Toggweiler1R. M. Key2J. L. Sarmiento3Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ, USAGeophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, P.O. Box 308, Princeton NJ, 08542, USAAtmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ, USAAtmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ, USAWe introduce a composite tracer for the marine system, Alk<sup>*</sup>, that has a global distribution primarily determined by CaCO<sub>3</sub> precipitation and dissolution. Alk<sup>*</sup> is also affected by riverine alkalinity from dissolved terrestrial carbonate minerals. We estimate that the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk<sup>*</sup> in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation results in low Alk<sup>*</sup> in subtropical gyres, especially in the Indian and Atlantic oceans. Upwelling of dissolved CaCO<sub>3</sub>-rich deep water elevates North Pacific and Southern Ocean Alk<sup>*</sup>. We use the Alk<sup>*</sup> distribution to estimate the variability of the calcite saturation state resulting from CaCO<sub>3</sub> cycling and other processes. We show that regional differences in surface calcite saturation state are due primarily to the effect of temperature differences on CO<sub>2</sub> solubility and, to a lesser extent, differences in freshwater content and air–sea disequilibria. The variations in net calcium carbonate cycling revealed by Alk<sup>*</sup> play a comparatively minor role in determining the calcium carbonate saturation state.http://www.biogeosciences.net/11/7349/2014/bg-11-7349-2014.pdf |
| spellingShingle | B. R. Carter J. R. Toggweiler R. M. Key J. L. Sarmiento Processes determining the marine alkalinity and calcium carbonate saturation state distributions Biogeosciences |
| title | Processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| title_full | Processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| title_fullStr | Processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| title_full_unstemmed | Processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| title_short | Processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| title_sort | processes determining the marine alkalinity and calcium carbonate saturation state distributions |
| url | http://www.biogeosciences.net/11/7349/2014/bg-11-7349-2014.pdf |
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