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| Titel |
Coral Patch seamount (NE Atlantic) – a sedimentological and megafaunal reconnaissance based on video and hydroacoustic surveys |
| VerfasserIn |
C. Wienberg, P. Wintersteller, L. Beuck, D. Hebbeln |
| 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 (2013-05-27), S.3421-3443 |
| Datensatznummer |
250018260
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| Publikation (Nr.) |
 copernicus.org/bg-10-3421-2013.pdf |
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| Zusammenfassung |
| The present study provides new knowledge about the so far largely unexplored
Coral Patch seamount which is located in the NE Atlantic Ocean half-way
between the Iberian Peninsula and Madeira. For the first time a detailed
hydroacoustic mapping (MBES) in conjunction with video surveys (ROV, camera
sled) were performed to describe the sedimentological and biological
characteristics of this sub-elliptical ENE-WSW elongated seamount. Video
observations were restricted to the southwestern summit area of Coral Patch
seamount (water depth: 560–760 m) and revealed that this part of the summit
is dominated by exposed hard substrate, whereas soft sediment is just a
minor substrate component. Although exposed hardgrounds are dominant for
this summit area and, thus, offer suitable habitat for settlement by benthic
organisms, the benthic megafauna shows rather scarce occurrence. In
particular, scleractinian framework-building cold-water corals are
apparently rare with very few isolated and small-sized live occurrences of
the species Lophelia pertusa and Madrepora oculata. In contrast, dead coral framework and coral rubble are
more frequent pointing to a higher abundance of cold-water corals on Coral
Patch during the recent past. This is even supported by the observation of
fishing lines that got entangled with rather fresh-looking coral frameworks.
Overall, long lines and various species of commercially important fish were
frequently observed emphasising the potential of Coral Patch as an important
target for fisheries that may have impacted the entire benthic community.
Hydroacoustic seabed classification covered the entire summit of Coral Patch
and its northern and southern flanks (water depth: 560–2660 m) and revealed
extended areas dominated by mixed and soft sediments at the northern flank
and to a minor degree at its easternmost summit and southern flank.
Nevertheless, these data also predict most of the summit area to be
dominated by exposed bedrock which would offer suitable habitat for benthic
organisms. By comparing the locally restricted video observations and the
broad-scale monitoring of a much larger and deeper seafloor area as derived
by hydroacoustic seabed classification, it becomes obvious that habitat
information obtained by in situ sampling may provide a rather scattered
pattern about the entire seamount ecosystem. Solely with a combination of
both methods, a satisfactory approach to describe the diverse
characteristics of a seamount ecosystem can be derived which is in turn
indispensable for future scientific monitoring campaigns as well as
management and conservation purposes. |
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