 |
| Titel |
Sensitivity of pelagic calcification to ocean acidification |
| VerfasserIn |
R. Gangstø, F. Joos, M. Gehlen |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 2 ; Nr. 8, no. 2 (2011-02-16), S.433-458 |
| Datensatznummer |
250005451
|
| Publikation (Nr.) |
 copernicus.org/bg-8-433-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| Ocean acidification might reduce the ability of calcifying plankton to
produce and maintain their shells of calcite, or of aragonite, the more
soluble form of CaCO3. In addition to possibly large biological
impacts, reduced CaCO3 production corresponds to a negative feedback on
atmospheric CO2. In order to explore the sensitivity of the ocean
carbon cycle to increasing concentrations of atmospheric CO2, we use
the new biogeochemical Bern3D/PISCES model. The model reproduces the large
scale distributions of biogeochemical tracers. With a range of sensitivity
studies, we explore the effect of (i) using different parameterizations of
CaCO3 production fitted to available laboratory and field experiments,
of (ii) letting calcite and aragonite be produced by auto- and heterotrophic
plankton groups, and of (iii) using carbon emissions from the range of the
most recent IPCC Representative Concentration Pathways (RCP). Under a
high-emission scenario, the CaCO3 production of all the model versions
decreases from ~1 Pg C yr−1 to between 0.36 and 0.82 Pg C yr−1
by the year 2100. The changes in CaCO3 production and
dissolution resulting from ocean acidification provide only a small feedback
on atmospheric CO2 of −1 to −11 ppm by the year 2100, despite the wide range
of parameterizations, model versions and scenarios included in our study. A
potential upper limit of the CO2-calcification/dissolution feedback of
−30 ppm by the year 2100 is computed by setting calcification to zero after
2000 in a high 21st century emission scenario. The similarity of feedback
estimates yielded by the model version with calcite produced by
nanophytoplankton and the one with calcite, respectively aragonite produced
by mesozooplankton suggests that expending biogeochemical
models to calcifying zooplankton might not be needed to simulate
biogeochemical impacts on the marine carbonate cycle. The changes in
saturation state confirm previous studies indicating that future
anthropogenic CO2 emissions may lead to irreversible changes in
ΩA for several centuries. Furthermore, due to the long-term changes in
the deep ocean, the ratio of open water CaCO3 dissolution to production
stabilizes by the year 2500 at a value that is 30–50% higher than at
pre-industrial times when carbon emissions are set to zero after 2100. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|