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| Titel |
Short-term post-mortality scavenging and longer term recovery after anoxia in the northern Adriatic Sea |
| VerfasserIn |
M. Blasnig, B. Riedel, L. Schiemer, M. Zuschin, M. Stachowitsch |
| 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. 11 ; Nr. 10, no. 11 (2013-11-26), S.7647-7659 |
| Datensatznummer |
250085440
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| Publikation (Nr.) |
 copernicus.org/bg-10-7647-2013.pdf |
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| Zusammenfassung |
| The northern Adriatic Sea is one of nearly 500 areas worldwide suffering
widespread mortalities due to anoxia. The present study documents post-anoxia
macrofauna dynamics after experimentally inducing small-scale anoxia in 24 m
depth (2 plots, each 50 cm × 50 cm). Time-lapse camera deployments
examined short-term scavenging of the moribund and dead organisms
(multi-species clumps consisting of sponges and ascidians) over two 3-day
periods (August 2009: 71.5 h, September 2009: 67.5 h). Longer term recovery
(days to 2 yr) in the same two plots was examined with an independent
photo series. Scavengers arrived quickly and in a distinct sequence: demersal
(Gobius niger, Serranus hepatus) and benthopelagic fishes
(Diplodus vulgaris, Pagellus erythrinus), followed by
hermit crabs (Paguristes eremita, showing a clear day/night rhythm
in presence) and gastropods (Hexaplex trunculus). This sequence is
attributed to the relative speeds and densities of the organisms. The sessile
fauna was largely removed or consumed within seven (August plot) and 13
(September plot) days after anoxia, confirming our first hypothesis that
decaying organisms are quickly utilised. The scavengers remained in dense
aggregations (e.g. up to 33 P. eremita individuals at one time) as
long as dead organisms were available. No recovery of sessile
macroepibenthos macroepibenthos
occurred in the experimental plots one and two years after anoxia,
undermining our second hypothesis that small denuded areas are more rapidly
recolonised. This study underlines the sensitivity of this soft-bottom
community and supports calls for reducing additional anthropogenic
disturbances such as fishing practices that further impede recolonisation and
threaten benthic community structure and function over the long term. |
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