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| Titel |
Density and distribution of megafauna at the Håkon Mosby mud volcano (the Barents Sea) based on image analysis |
| VerfasserIn |
E. Rybakova (Goroslavskaya), S. Galkin, M. Bergmann, T. Soltwedel, A. Gebruk |
| 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 (2013-05-21), S.3359-3374 |
| Datensatznummer |
250018256
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| Publikation (Nr.) |
 copernicus.org/bg-10-3359-2013.pdf |
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| Zusammenfassung |
| During a survey of the Håkon Mosby mud volcano (HMMV), located on the
Bear Island fan in the southwest Barents Sea at ∼1250 m water depth,
different habitats inside the volcano caldera and outside it were
photographed using a towed camera platform, an Ocean Floor Observation System
(OFOS). Three transects were performed across the caldera and one outside, in
the background area, each transect was ∼2 km in length. We compared
the density, taxa richness and diversity of nonsymbiotrophic megafauna in
areas inside the volcano caldera with different bacterial mat and
pogonophoran tubeworm cover. Significant variations in megafaunal
composition, density and distribution were found between considered areas.
Total megafaunal density was highest in areas of dense pogonophoran
populations (mean 52.9 ind. m−2) followed by areas of plain
light-coloured sediment that were devoid of bacterial mats and tube worms
(mean 37.7 ind. m−2). The lowest densities were recorded in areas of
dense bacterial mats (mean ≤1.4 ind. m−2). Five taxa
contributed to most of the observed variation: the ophiuroid
Ophiocten gracilis, lysianassid amphipods, the pycnogonid
Nymphon macronix, the caprellid Metacaprella horrida and
the fish Lycodes squamiventer. In agreement with previous studies,
three zones within the HMMV caldera were distinguished, based on different
habitats and megafaunal composition: "bacterial mats", "pogonophoran
fields" and "plain light-coloured sediments". The zones were arranged
almost concentrically around the central part of the caldera that was devoid
of visible megafauna. The total number of taxa showed little variation inside
(24 spp.) and outside the caldera (26 spp.). The density, diversity and
composition of megafauna varied substantially between plain light-coloured
sediment areas inside the caldera and the HMMV background. Megafaunal density
was lower in the background (mean 25.3 ind. m−2) compared to areas of
plain light-coloured sediments inside the caldera. So the effect of the
mud-volcano environment on benthic communities is expressed in increasing of
biomass, changing of taxa composition and proportions of most taxonomic
groups. |
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