 |
| Titel |
Modelling coral polyp calcification in relation to ocean acidification |
| VerfasserIn |
S. Hohn, A. Merico |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 11 ; Nr. 9, no. 11 (2012-11-13), S.4441-4454 |
| Datensatznummer |
250007387
|
| Publikation (Nr.) |
 copernicus.org/bg-9-4441-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| Rising atmospheric CO2 concentrations due to anthropogenic emissions
induce changes in the carbonate chemistry of the oceans and, ultimately, a
drop in ocean pH. This acidification process can harm calcifying organisms
like coccolithophores, molluscs, echinoderms, and corals. It is expected that
ocean acidification in combination with other anthropogenic stressors will
cause a severe decline in coral abundance by the end of this century, with
associated disastrous effects on reef ecosystems. Despite the growing
importance of the topic, little progress has been made with respect to
modelling the impact of acidification on coral calcification. Here we present
a model for a coral polyp that simulates the carbonate system in four
different compartments: the seawater, the polyp tissue, the coelenteron, and
the calcifying fluid. Precipitation of calcium carbonate takes place in the
metabolically controlled calcifying fluid beneath the polyp tissue. The model
is adjusted to a state of activity as observed by direct microsensor
measurements in the calcifying fluid. We find that a transport mechanism for
bicarbonate is required to supplement carbon into the calcifying fluid
because CO2 diffusion alone is not sufficient to sustain the observed
calcification rates. Simulated CO2 perturbation experiments reveal
decreasing calcification rates under elevated pCO2 despite the strong
metabolic control of the calcifying fluid. Diffusion of CO2 through the
tissue into the calcifying fluid increases with increasing seawater
pCO2,
leading to decreased aragonite saturation in the calcifying fluid.
Our modelling study provides important insights into the
complexity of the calcification process at the organism level and helps to
quantify the effect of ocean acidification on corals. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|