Calcium carbonate corrosivity in an Alaskan inland sea
Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO<sub>2</sub>, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO<sub>3</sub>) saturation states (Ω) to levels...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-01-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/365/2014/bg-11-365-2014.pdf |
| _version_ | 1818538771853869056 |
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| author | W. Evans J. T. Mathis J. N. Cross |
| author_facet | W. Evans J. T. Mathis J. N. Cross |
| author_sort | W. Evans |
| collection | DOAJ |
| description | Ocean acidification is the hydrogen ion increase caused by the oceanic uptake
of anthropogenic CO<sub>2</sub>, and is a focal point in marine biogeochemistry, in
part, because this chemical reaction reduces calcium carbonate (CaCO<sub>3</sub>)
saturation states (Ω) to levels that are corrosive (i.e., Ω ≤
1) to shell-forming marine organisms. However, other processes can drive
CaCO<sub>3</sub> corrosivity; specifically, the addition of tidewater glacial melt.
Carbonate system data collected in May and September from 2009 through 2012
in Prince William Sound (PWS), a semienclosed inland sea located on the
south-central coast of Alaska and ringed with fjords containing tidewater
glaciers, reveal the unique impact of glacial melt on CaCO<sub>3</sub> corrosivity.
Initial limited sampling was expanded in September 2011 to span large
portions of the western and central sound, and included two fjords proximal
to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in
these fjords affected CaCO<sub>3</sub> corrosivity in the upper water column
(< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode
water with near-corrosive Ω levels seen below the mixed layer over a
portion of the sound, and (2) as point sources for surface plumes of glacial
melt with corrosive Ω levels (Ω for aragonite and calcite
down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures
(<i>p</i>CO<sub>2</sub>) well below atmospheric levels. CaCO<sub>3</sub> corrosivity in
glacial melt plumes is poorly reflected by <i>p</i>CO<sub>2</sub> or pH<sub>T</sub>,
indicating that either one of these carbonate parameters alone would fail to
track Ω in PWS. The unique Ω and <i>p</i>CO<sub>2</sub> conditions in the
glacial melt plumes enhances atmospheric CO<sub>2</sub> uptake, which, if not
offset by mixing or primary productivity, would rapidly exacerbate CaCO<sub>3</sub>
corrosivity in a positive feedback. The cumulative effects of glacial melt
and air–sea gas exchange are likely responsible for the seasonal reduction of
Ω in PWS, making PWS highly sensitive to increasing atmospheric
CO<sub>2</sub> and amplified CaCO<sub>3</sub> corrosivity. |
| first_indexed | 2024-12-11T21:33:17Z |
| format | Article |
| id | doaj.art-96a5b31d6490473f814a162823fd7567 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-11T21:33:17Z |
| publishDate | 2014-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-96a5b31d6490473f814a162823fd75672022-12-22T00:50:06ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-01-0111236537910.5194/bg-11-365-2014Calcium carbonate corrosivity in an Alaskan inland seaW. Evans0J. T. Mathis1J. N. Cross2Ocean Acidification Research Center, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USAOcean Acidification Research Center, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USAOcean Acidification Research Center, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USAOcean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO<sub>2</sub>, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO<sub>3</sub>) saturation states (Ω) to levels that are corrosive (i.e., Ω ≤ 1) to shell-forming marine organisms. However, other processes can drive CaCO<sub>3</sub> corrosivity; specifically, the addition of tidewater glacial melt. Carbonate system data collected in May and September from 2009 through 2012 in Prince William Sound (PWS), a semienclosed inland sea located on the south-central coast of Alaska and ringed with fjords containing tidewater glaciers, reveal the unique impact of glacial melt on CaCO<sub>3</sub> corrosivity. Initial limited sampling was expanded in September 2011 to span large portions of the western and central sound, and included two fjords proximal to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in these fjords affected CaCO<sub>3</sub> corrosivity in the upper water column (< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer over a portion of the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (<i>p</i>CO<sub>2</sub>) well below atmospheric levels. CaCO<sub>3</sub> corrosivity in glacial melt plumes is poorly reflected by <i>p</i>CO<sub>2</sub> or pH<sub>T</sub>, indicating that either one of these carbonate parameters alone would fail to track Ω in PWS. The unique Ω and <i>p</i>CO<sub>2</sub> conditions in the glacial melt plumes enhances atmospheric CO<sub>2</sub> uptake, which, if not offset by mixing or primary productivity, would rapidly exacerbate CaCO<sub>3</sub> corrosivity in a positive feedback. The cumulative effects of glacial melt and air–sea gas exchange are likely responsible for the seasonal reduction of Ω in PWS, making PWS highly sensitive to increasing atmospheric CO<sub>2</sub> and amplified CaCO<sub>3</sub> corrosivity.http://www.biogeosciences.net/11/365/2014/bg-11-365-2014.pdf |
| spellingShingle | W. Evans J. T. Mathis J. N. Cross Calcium carbonate corrosivity in an Alaskan inland sea Biogeosciences |
| title | Calcium carbonate corrosivity in an Alaskan inland sea |
| title_full | Calcium carbonate corrosivity in an Alaskan inland sea |
| title_fullStr | Calcium carbonate corrosivity in an Alaskan inland sea |
| title_full_unstemmed | Calcium carbonate corrosivity in an Alaskan inland sea |
| title_short | Calcium carbonate corrosivity in an Alaskan inland sea |
| title_sort | calcium carbonate corrosivity in an alaskan inland sea |
| url | http://www.biogeosciences.net/11/365/2014/bg-11-365-2014.pdf |
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