Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system
There are concerns that Mg-calcite crustose coralline algae (CCA), which are key reef builders on coral reefs, will be most susceptible to increased rates of dissolution under higher <i>p</i>CO<sub>2</sub> and ocean acidification. Due to the higher solubility of Mg-calcite, i...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-09-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/5247/2015/bg-12-5247-2015.pdf |
| _version_ | 1819259000296833024 |
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| author | M. C. Nash S. Uthicke A. P. Negri N. E. Cantin |
| author_facet | M. C. Nash S. Uthicke A. P. Negri N. E. Cantin |
| author_sort | M. C. Nash |
| collection | DOAJ |
| description | There are concerns that Mg-calcite crustose coralline algae (CCA), which are
key reef builders on coral reefs, will be most susceptible to increased rates
of dissolution under higher <i>p</i>CO<sub>2</sub> and ocean acidification. Due to the
higher solubility of Mg-calcite, it has been hypothesised that magnesium
concentrations in CCA Mg-calcite will decrease as the ocean acidifies, and
that this decrease will make their skeletons more chemically stable. In
addition to Mg-calcite, CCA <i>Porolithon onkodes</i>, the predominant
encrusting species on tropical reefs, can have dolomite
(Ca<sub>0.5</sub>Mg<sub>0.5</sub>CO<sub>3</sub>) infilling cell spaces which increases their
stability. However, nothing is known about how bio-mineralised dolomite
formation responds to higher <i>p</i>CO<sub>2</sub>. Using <i>P. onkodes</i> grown for
3 and 6 months in tank experiments, we aimed to determine (1) if mol %
MgCO<sub>3</sub> in new crust and new settlement was affected by increasing
CO<sub>2</sub> levels (365, 444, 676 and 904 μatm), (2) whether
bio-mineralised dolomite formed within these time frames, and (3) if so,
whether this was effected by CO<sub>2</sub>. Our results show that there was no
significant effect of CO<sub>2</sub> on mol % MgCO<sub>3</sub> in any sample set,
indicating an absence of a plastic response under a wide range of
experimental conditions. Dolomite within the CCA cells formed within 3 months
and dolomite abundance did not vary significantly with CO<sub>2</sub> treatment.
While evidence mounts that climate change will impact many sensitive coral
and CCA species, the results from this study indicate that reef-building
<i>P. onkodes</i> will continue to form stabilising dolomite infill under
near-future acidification conditions, thereby retaining its higher resistance
to dissolution. |
| first_indexed | 2024-12-23T19:03:03Z |
| format | Article |
| id | doaj.art-9d8a6fb1505b48dbac44a42790d149b9 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-23T19:03:03Z |
| publishDate | 2015-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-9d8a6fb1505b48dbac44a42790d149b92022-12-21T17:34:41ZengCopernicus PublicationsBiogeosciences1726-41701726-41892015-09-0112175247526010.5194/bg-12-5247-2015Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental systemM. C. Nash0S. Uthicke1A. P. Negri2N. E. Cantin3Research School of Physics, Australian National University, Canberra, 0200, AustraliaAustralian Institute of Marine Science, Townsville, Queensland, 4810, AustraliaAustralian Institute of Marine Science, Townsville, Queensland, 4810, AustraliaAustralian Institute of Marine Science, Townsville, Queensland, 4810, AustraliaThere are concerns that Mg-calcite crustose coralline algae (CCA), which are key reef builders on coral reefs, will be most susceptible to increased rates of dissolution under higher <i>p</i>CO<sub>2</sub> and ocean acidification. Due to the higher solubility of Mg-calcite, it has been hypothesised that magnesium concentrations in CCA Mg-calcite will decrease as the ocean acidifies, and that this decrease will make their skeletons more chemically stable. In addition to Mg-calcite, CCA <i>Porolithon onkodes</i>, the predominant encrusting species on tropical reefs, can have dolomite (Ca<sub>0.5</sub>Mg<sub>0.5</sub>CO<sub>3</sub>) infilling cell spaces which increases their stability. However, nothing is known about how bio-mineralised dolomite formation responds to higher <i>p</i>CO<sub>2</sub>. Using <i>P. onkodes</i> grown for 3 and 6 months in tank experiments, we aimed to determine (1) if mol % MgCO<sub>3</sub> in new crust and new settlement was affected by increasing CO<sub>2</sub> levels (365, 444, 676 and 904 μatm), (2) whether bio-mineralised dolomite formed within these time frames, and (3) if so, whether this was effected by CO<sub>2</sub>. Our results show that there was no significant effect of CO<sub>2</sub> on mol % MgCO<sub>3</sub> in any sample set, indicating an absence of a plastic response under a wide range of experimental conditions. Dolomite within the CCA cells formed within 3 months and dolomite abundance did not vary significantly with CO<sub>2</sub> treatment. While evidence mounts that climate change will impact many sensitive coral and CCA species, the results from this study indicate that reef-building <i>P. onkodes</i> will continue to form stabilising dolomite infill under near-future acidification conditions, thereby retaining its higher resistance to dissolution.http://www.biogeosciences.net/12/5247/2015/bg-12-5247-2015.pdf |
| spellingShingle | M. C. Nash S. Uthicke A. P. Negri N. E. Cantin Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system Biogeosciences |
| title | Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system |
| title_full | Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system |
| title_fullStr | Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system |
| title_full_unstemmed | Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system |
| title_short | Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, <i>Porolithon onkodes</i> in an experimental system |
| title_sort | ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae i porolithon onkodes i in an experimental system |
| url | http://www.biogeosciences.net/12/5247/2015/bg-12-5247-2015.pdf |
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