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| Titel |
Whole-system metabolism and CO2 fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean) |
| VerfasserIn |
F. Gazeau, C. M. Duarte, J.-P. Gattuso, C. Barrón, N. Navarro, S. Ruiz, Y. T. Prairie, M. Calleja, B. Delille, M. Frankignoulle, A. V. Borges |
| 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 ; 2, no. 1 ; Nr. 2, no. 1 (2005-02-23), S.43-60 |
| Datensatznummer |
250000378
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| Publikation (Nr.) |
 copernicus.org/bg-2-43-2005.pdf |
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| Zusammenfassung |
| Planktonic and benthic incubations (bare and Posidonia oceanica vegetated sediments) were
performed at monthly intervals from March 2001 to October 2002 in a seagrass
vegetated area of the Bay of Palma (Mallorca, Spain). Results showed a
contrast between the planktonic compartment, which was on average near
metabolic balance (−4.6±5.9 mmol O2 m-2 d-1) and the
benthic compartment, which was autotrophic (17.6±8.5 mmol O2
m-2 d-1). During two cruises in March and June 2002, planktonic
and benthic incubations were performed at several stations in the bay to
estimate the whole-system metabolism and to examine its relationship with
partial pressure of CO2 (pCO2) and apparent oxygen utilisation
(AOU) spatial patterns. Moreover, during the second cruise, when the
residence time of water was long enough, net ecosystem production (NEP)
estimates based on incubations were compared, over the Posidonia oceanica meadow, to rates
derived from dissolved inorganic carbon (DIC) and oxygen (O2) mass
balance budgets. These budgets provided NEP estimates in fair agreement with
those derived from direct metabolic estimates based on incubated samples
over the Posidonia oceanica meadow. Whereas the seagrass community was autotrophic, the excess
organic carbon production therein could only balance the planktonic
heterotrophy in shallow waters relative to the maximum depth of the bay (55 m).
This generated a horizontal gradient from autotrophic or balanced
communities in the shallow seagrass-covered areas, to strongly heterotrophic
communities in deeper areas of the bay. It seems therefore that, on an
annual scale in the whole bay, the organic matter production by the
Posidonia oceanica may not be sufficient to fully compensate the heterotrophy of the
planktonic compartment, which may require external organic carbon inputs,
most likely from land. |
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