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| Titel |
Major consequences of an intense dense shelf water cascading event on deep-sea benthic trophic conditions and meiofaunal biodiversity |
| VerfasserIn |
A. Pusceddu, M. Mea, M. Canals, S. Heussner, X. Durrieu de Madron, A. Sanchez-Vidal, S. Bianchelli, C. Corinaldesi, A. Dell'Anno, 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. 4 ; Nr. 10, no. 4 (2013-04-22), S.2659-2670 |
| Datensatznummer |
250018211
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| Publikation (Nr.) |
 copernicus.org/bg-10-2659-2013.pdf |
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| Zusammenfassung |
| Numerous submarine canyons around the world are preferential conduits for
episodic dense shelf water cascading (DSWC), which quickly modifies physical
and chemical ambient conditions while transporting large amounts of material
towards the base of slope and basin. Observations conducted during the last
20 yr in the Lacaze-Duthiers and Cap de Creus canyons (Gulf of Lion, NW
Mediterranean Sea) report several intense DSWC events. The effects of DSWC
on deep-sea ecosystems are almost unknown. To investigate the effects of
these episodic events, we analysed changes in the meiofaunal biodiversity
inside and outside the canyon. Sediment samples were collected at depths
varying from ca. 1000 to > 2100 m in May 2004 (before a major
event), April 2005 (during a major cascading event) and in October 2005,
August 2006, April 2008 and April 2009 (after a major event). We report here
that the late winter–early spring 2005 cascading led to a reduction of the
organic matter contents in canyon floor sediments down to 1800 m depth,
whereas surface sediments at about 2200 m depth showed an increase. Our
findings suggest that the nutritional material removed from the shallower
continental shelf, canyon floor and flanks, and also the adjacent open slope
was rapidly transported to the deep margin. During the cascading event the
meiofaunal abundance and biodiversity in the studied deep-sea sediments were
significantly lower than after the event. Benthic assemblages during the cascading
were significantly different from those in all other sampling periods in
both the canyon and deep margin. After only six months from the cessation of
the cascading, benthic assemblages in the impacted sediments were again
similar to those observed in other sampling periods, thus illustrating a
quick recovery. Since the present climate change is expected to increase the
intensity and frequency of these episodic events, we anticipate that they
will increasingly affect benthic bathyal ecosystems, which may eventually
challenge their resilience. |
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