Figure 1.
Wood experiments deployed in the Eastern Mediterranean deep sea during the BIONIL cruise in 2006 (RV Meteor) and recovered during the Medeco-2 expedition (RV Pourquoi Pas?) in 2007.
a, b) Wood#1 close to carbonate crust, c, d) Wood#2 on carbonate crust, e, f) Wood#5 on sediment. (Pictures a, c, e are courtesy of Marum, University Bremen, Germany; Pictures b, d, f are courtesy of Ifremer, France).
Table 1.
Locations of the four wood colonization experiments and PANGAEA references for deployment and recovery of the experiments.
Figure 2.
The Pockmark area in the Central Province of the Nile deep-sea fan in the Eastern Mediterranean with locations of the four wood colonization experiments: Wood#1 close to carbonate crust, wood#2 on carbonate crust, wood#5 on sediment, wood#6 close to carbonate crust, sampled after less than 1 day of submersion.
The maps were generated in ArcMap (ArcGIS Desktop 9.3) with continental margins provided by ESRI (Kranzberg, Germany) and bathymetry obtained from the 2-minute Gridded Global Relief Data ETOPO2v2 (2006, http://www.ngdc.noaa.gov/mgg/fliers/06mgg01.html). The bathymetry of the Pockmark Area was obtained during Meteor expedition M70/2 (BIONIL) using AUV Asterx equipped with EM120 multibeam (IFREMER/Geosciences Azur).
Figure 3.
Macrofauna colonizing the wood experiments after one year at the sea floor.
a) Xylophaga dorsalis, b) Idas modiolaeformis, c) Glycera noelae sp. nov. d) Cryptonome gen. nov. conclava, n. sp., e) Phascolosoma turnerae, f) Asterechinus elegans, g) Bathynectes piperitus, h) unidentified deep-sea fish, i, k) unidentified species of amphipods, l) unidentified species of Leptostracea. (Pictures h, g, f are courtesy of Ifremer, France (Medeco-2 expedition))
Figure 4.
Ex situ microsensor measurements of oxygen, sulfide and pH at (0.5 m) and away (10 m) from wood experiments #1 and #5.
Note the different scales for sulfide concentrations.
Table 2.
Summary of biogeochemical measurements at the wood experiments and at selected seep and reference sites.
Figure 5.
Total bacterial cell numbers at (0.5 m) and away (10m) from wood experiments #1 and #5.
Figure 6.
Non-metric multidimensional scaling (NMDS) ordination of relative ARISA OTU abundances with Bray-Curtis distance.
Each point represents the consensus of 2–3 replicate ARISA profiles. Colors and groupings indicate the origin of the samples. a includes a comparison only of the wood experiments, while b and c show bacterial community structure on the wood experiments in comparison to surrounding sediments at distances of 0.5 m and 10 m from the wood experiments. Asterisks (*) indicate the presence of wood chips in a sample.
Figure 7.
Bacterial community composition of the wood experiments at the class level.
Wood#6 served as a control and was sampled after less than 1 day of submergence. Wood experiments #1, #2 and #5 had been submerged for 1 year.
Table 3.
Most common bacterial classes in decreasing order of their relative sequence abundances in wood experiments submerged for 1 day or 1 year, and in wood-influenced or non-wood influenced sediments.
Figure 8.
Schematic illustration of the proposed succession of a wood fall during the first year at the deep-sea floor.
Organisms shown on inlets from left to right: amphipods and one other type of unidentified crustacean, wood-boring bivalve Xylophaga dorsalis, polychaete Glycera noelae sp. nov., polychaete Cryptonome gen. nov. conclava, n. sp., sipunculid Phascolosoma turnerae, chemosynthetic bivalve Idas modiolaeformis, DAPI-stained bacteria with pieces of wood (Illustration: Sabine Lüdeling, Medieningenieure).