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| Titel |
Photosynthetic activity buffers ocean acidification in seagrass meadows |
| VerfasserIn |
I. E. Hendriks, Y. S. Olsen, L. Ramajo, L. Basso, A. Steckbauer, T. S. Moore, J. Howard, C. M. Duarte |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-28), S.333-346 |
| Datensatznummer |
250117146
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| Publikation (Nr.) |
 copernicus.org/bg-11-333-2014.pdf |
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| Zusammenfassung |
Macrophytes growing in shallow coastal zones characterised by intense
metabolic activity have the capacity to modify pH within their canopy and
beyond. We observed diel pH changes in shallow (5–12 m) seagrass
(Posidonia oceanica) meadows spanning 0.06 pH units in September to
0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation
state (ΩAr)) and O2 within the meadows displayed strong
diel variability driven by primary productivity, and changes in chemistry
were related to structural parameters of the meadow, in particular, the leaf
surface area available for photosynthesis (LAI). LAI was positively
correlated to mean, max and range pHNBS and max and range
ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy)
influenced max and min ΩAr, while in September there was no
effect of hydrodynamics on the carbonate system within the canopy. Max and
range ΩAr within the meadow showed a positive trend with the
calcium carbonate load of the leaves, pointing to a possible link between
structural parameters, ΩAr and carbonate deposition.
Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit
from the modification of the carbonate system by the meadow. There is,
however, concern for the ability of seagrasses to provide modifications of
similar importance in the future. The predicted decline of seagrass meadows
may alter the scope for alteration of pH within a seagrass meadow and in the
water column above the meadow, particularly if shoot density and biomass
decline, on which LAI is based. Organisms associated with seagrass
communities may therefore suffer from the loss of pH buffering capacity in
degraded meadows. |
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