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| Titel |
Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia |
| VerfasserIn |
A. Dell'Anno, A. Pusceddu, C. Corinaldesi, M. Canals, S. Heussner, L. Thomsen, R. Danovaro |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2013-05-02), S.2945-2957 |
| Datensatznummer |
250018231
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| Publikation (Nr.) |
 copernicus.org/bg-10-2945-2013.pdf |
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| Zusammenfassung |
| The bioavailability of organic matter in benthic deep-sea ecosystems,
commonly used to define their trophic state, can greatly influence key
ecological processes such as biomass production and nutrient cycling. Here,
we assess the trophic state of deep-sea sediments from open slopes and
canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic)
continental margins, offshore east and west Iberia, respectively, by using a
biomimetic approach based on enzymatic digestion of protein and carbohydrate
pools. Patterns of sediment trophic state were analyzed in relation to
increasing water depth, including repeated samplings over a 3 yr period
in the Catalan margin. Two out of the three sampling periods occurred a few
months after dense shelf water cascading events. The benthic deep-sea
ecosystems investigated in this study were characterized by high amounts of
bioavailable organic matter when compared to other deep-sea sediments.
Bioavailable organic matter and its nutritional value were significantly
higher in the Portuguese margin than in the Catalan margin, thus reflecting
differences in primary productivity of surface waters reported for the two
regions. Similarly, sediments of the Catalan margin were characterized by
significantly higher food quantity and quality in spring, when the
phytoplankton bloom occurs in surface waters, than in summer and autumn.
Differences in the benthic trophic state of canyons against open slopes were
more evident in the Portuguese than in the Catalan margin. In both
continental margins, bioavailable organic C concentrations did not vary or
increase with increasing water depth. Overall, our findings suggest that the
intensity of primary production processes along with the lateral transfer of
organic particles, even amplified by episodic events, can have a role in
controlling the quantity and distribution of bioavailable organic detritus
and its nutritional value along these continental margin ecosystems. |
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