FN Archimer Export Format
PT J
TI Fauna and habitat types driven by turbidity currents in the lobe complex of the Congo deep sea fan
BT 
AF SEN, Arunima
   DENNIELOU, Bernard
   TOUROLLE, Julie
   ARNAUBEC, Aurelien
   RABOUILLE, Christophe
   OLU, Karine
AS 1:1;2:2;3:1;4:3;5:4;6:1;
FF 1:PDG-REM-EEP-LEP;2:PDG-REM-GM-LGS;3:PDG-REM-EEP-LEP;4:PDG-IMN-SM-PRAO;5:;6:PDG-REM-EEP-LEP;
C1 IFREMER, Ctr Bretagne, Lab Environm Profond, Plouzane, France.
   IFREMER, Ctr Bretagne, Lab Geodynam & Enregistrement Sedimentaire, Unite Rech Geosci Marines, Plouzane, France.
   IFREMER, Ctr Mediterranee, Unite Syst Marines, La Seyne Sur Mer, France.
   Univ Paris Saclay, Lab Sci Climat & Environm, Gif Sur Yvette, France.
C2 IFREMER, FRANCE
   IFREMER, FRANCE
   IFREMER, FRANCE
   UNIV PARIS SACLAY, FRANCE
SI BREST
   TOULON
SE PDG-REM-EEP-LEP
   PDG-REM-GM-LGS
   PDG-IMN-SM-PRAO
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 2.451
TC 21
UR https://archimer.ifremer.fr/doc/00385/49614/50126.pdf
LA English
DT Article
CR CONGOLOBE
   WACS
BO Pourquoi pas ?
AB This study characterizes the habitats and megafaunal community of the Congo distal lobe complex driven by turbidity currents through the use of remotely operated vehicle (ROV) still imagery transects covering distances in the order of kilometers. In this sedimentary, abyssal area about 5000 m deep and 750 km offshore from western Africa, large quantities of deposited organic material supplied by the Congo River canyon and channel support aggregations of large sized foraminifers (Bathysiphon sp.) and vesicomyid clams (Christineconcha regab, Abyssogena southwardae) often associated with methane cold seeps, as well as opportunistic deep-sea scavengers. Additionally, bacterial mats, assumed to be formed by large sulfur-oxidizing filamentous bacteria (Beggiatoa type), and black patches of presumably reduced sediment were seen which are, together with sulfur-oxidizing symbiont- bearing vesicomyids, indicators of sulfide-rich sediments. Habitat and faunal distribution were analyzed in relation to the microtopography obtained with the ROV multibeam echosounder, at three sites from the entrance of the lobe complex where the channel is still deep, to the main, flatter area of turbidite deposition. Specific characteristics of the system influence animal distributions: both the forams and the vesicomyid clams tended to avoid the channels characterized by high-speed currents, and are therefore preferentially located along channel flanks affected by sliding, and on levees formed by channel overspill. Foram fields are found in flat areas and form large fields, whereas the vesicomyids have a patchy distribution and appear to show a preference for regions of local topographical relief such as slide scars or collapsed blocks of sediments, which likely facilitate sulfide exhumation. The colonization of sulfide rich sediments by vesicomyids is limited, but nonetheless was seen to occur in the main deposition area where they have to cope with very high sedimentation rates (up to 20 cm/yr) and frequent turbidity currents. Other biological adaptations to the local conditions likely determine the presence and survival of animals in the system: large agglutinated forams are known to be adept at quickly colonizing disturbed sediment and capitalizing on abundant but irregular food sources, and vesicomyid clams have a mobile lifestyle that enables them to maintain their population in the ever changing landscape of sulfide-rich sediment outcrops. Turbiditic systems appear to be intermediate between other energy rich habitats sustaining chemosynthesis in the deep sea, being locally less stable in terms of energy supply than cold seeps, limiting the number of cold-seep specialists able to colonize, but constituting a longer lived habitat than food falls. Turbidite fans therefore represent distinct deep sea habitats that contribute to sustaining populations of both chemosynthesis-based and opportunistic taxa in the deep-sea. 
PY 2017
PD AUG
SO Deep-sea Research Part Ii-topical Studies In Oceanography
SN 0967-0645
PU Pergamon-elsevier Science Ltd
VL 142
UT 000408783500012
BP 167
EP 179
DI 10.1016/j.dsr2.2017.05.009
ID 49614
ER

EF