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| Titel |
Evaluation of coral reef carbonate production models at a global scale |
| VerfasserIn |
N. S. Jones, A. Ridgwell, E. J. Hendy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 5 ; Nr. 12, no. 5 (2015-03-04), S.1339-1356 |
| Datensatznummer |
250117840
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| Publikation (Nr.) |
 copernicus.org/bg-12-1339-2015.pdf |
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| Zusammenfassung |
| Calcification by coral reef communities is estimated to account for half of
all carbonate produced in shallow water environments and more than 25%
of the total carbonate buried in marine sediments globally. Production of
calcium carbonate by coral reefs is therefore an important component of the
global carbon cycle; it is also threatened by future global warming and
other global change pressures. Numerical models of reefal carbonate
production are needed for understanding how carbonate deposition responds to
environmental conditions including atmospheric CO2 concentrations in
the past and into the future. However, before any projections can be made,
the basic test is to establish model skill in recreating present-day
calcification rates. Here we evaluate four published model descriptions of
reef carbonate production in terms of their predictive power, at both local
and global scales. We also compile available global data on reef
calcification to produce an independent observation-based data set for the
model evaluation of carbonate budget outputs. The four calcification models
are based on functions sensitive to combinations of light availability,
aragonite saturation (Ωa) and temperature and were implemented
within a specifically developed global framework, the Global Reef Accretion
Model (GRAM). No model was able to reproduce independent rate estimates of
whole-reef calcification, and the output from the temperature-only based
approach was the only model to significantly correlate with
coral-calcification rate observations. The absence of any predictive power
for whole reef systems, even when consistent at the scale of individual
corals, points to the overriding importance of coral cover estimates in the
calculations. Our work highlights the need for an ecosystem modelling
approach, accounting for population dynamics in terms of mortality and
recruitment and hence calcifier abundance, in estimating global reef
carbonate budgets. In addition, validation of reef carbonate budgets is
severely hampered by limited and inconsistent methodology in reef-scale
observations. |
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