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| Titel |
The trophic biology of the holothurian Molpadia musculus: implications for organic matter cycling and ecosystem functioning in a deep submarine canyon |
| VerfasserIn |
T. Amaro, S. Bianchelli, D. S. M. Billett, M. R. Cunha, A. Pusceddu, 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 ; 7, no. 8 ; Nr. 7, no. 8 (2010-08-16), S.2419-2432 |
| Datensatznummer |
250004930
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| Publikation (Nr.) |
 copernicus.org/bg-7-2419-2010.pdf |
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| Zusammenfassung |
| Megafaunal organisms play a key role in ecosystem functioning in the
deep-sea through bioturbation, bioirrigation and organic matter cycling. At
3500 m water depth in the Nazaré Canyon, NE Atlantic, very high
abundances of the infaunal holothurian Molpadia musculus were observed. To quantify the role
of M. musculus in sediment cycling, sediment samples and holothurians were collected
using an ROV and in situ experiments were conducted with incubation chambers. The
biochemical composition of the sediment (in terms of proteins, carbohydrates
and lipids), the holothurians' gut contents and holothurians' faecal
material were analysed. In the sediments, proteins were the dominant organic
compound, followed by carbohydrates and lipids. In the holothurian's gut
contents, protein concentrations were higher than the other compounds,
decreasing significantly as the material passed through the digestive tract.
Approximately 33±1% of the proteins were digested by the time
sediment reached the mid gut, with a total digestion rate equal to 67±1%.
Carbohydrates and lipids were ingested in smaller amounts and
digested with lower efficiencies (23±11% and 50±11%,
respectively). As a result, the biopolymeric C digestion rate was on average
62±3%. We estimated that the population of M. musculus could remove
approximately 0.49±0.13 g biopolymeric C and 0.13±0.03 g N m−2 d−1
from the sediments. These results suggest that M. musculus plays a
key role in the benthic tropho-dynamics and biogeochemical processes in the
Nazaré Canyon. |
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