PRELIMINARY RESULTS
 

Sampling Stations
         The cruise track spanned 275 n. mi. (Figure 2). Thirty-three sampling stations were completed (Appendix I, Table 2). Viosca Knoll 906-907 was visited for two days (30-31^st July, Figure 5), and Viosca Knoll 826 was visited for three days (1-3^rd August, Figure 6). On the night of the 2^nd and early morning of the 3^rd, the boat steamed south of the Ludwig & Walton site to conduct two off-reef bottom trawls and one CTD cast. During the last day of sampling, August 4^th 2004, CEC Sites 4 and 5 were visited (Figure 7).

Figure 5.  Stations sampled at the Viosca Knoll 906-907 sampling site (MMS leg I).

Figure 6.  Stations sampled at the Viosca Knoll 826 sampling site (MMS leg I).

Echosounder Surveys
         Echosounding transects revealed a dynamic topography on the seabed along the 500 m isobath. A previously unknown Lophelia site we named "Big Blue Reef" was located during one of our surveys (Figure 3). Submersible investigations of the area documented the greatest extent of Lophelia colonies from among all known GOM Lophelia sites (Figure 8).

Submersible
       Twelve dives were completed using the JSLI corresponding to dives USGS-GM-2004-03-JSL-4744 through USGS-GM-2004-03-JSL-4755 (Appendix I, Table 3). Four dives were conducted in the area of Viosca Knoll 906-907 (Figure 5), six dives in the area of Viosca Knoll 826 (Figure 6), one dive in the area of CEC 4 (Figure 7), and one dive in the area of CEC 5 (Figure 5). Over these dives, 84 hours of video were taken which includes Digital-S, miniDV, and internal Handicam video (Appendix I, Table 4). Two hundred digital still pictures were taken during the twelve dives including numerous shots of the Lophelia community and adjacent non-structured habitat (Appendix I, Table 5). Audio recordings were made during each dive by scientists in both the bow and stern compartments. All of the audio recordings have been transcribed to paper logs. The audio log will be used to document the predominant habitat transversed during a dive.

Fish/Invertebrate Collection
       Fish specimens were collected (n=332) using a variety of techniques including submersible suction sampling (with rotenone), four trawling stations, two longline stations, two benthic sled stations, two angling stations, and five dipnet stations. Fish collected represented 48 different species (Appendix I, Table 6). From these specimens 196 stomach samples (Appendix I, Table 7) were taken and 37 individuals were photographed (Appendix I, Table 8).

         Invertebrates collected represented almost 70 different species from various phyla (Appendix I, Table 9), including octocorallians (i.e., soft corals), scleractinian corals, polychaetes (including chemosynthetic tube worms), arthropods (crabs, shrimps, pycnogonids), echinoderms (sea stars, brittle stars, urchins, crinoids), and molluscs (gastropods, squid, octopus).  Thirty-five different invertebrate specimens were photographed (Appendix I, Table 8). Eleven sediment samples were collected both near and away from Lophelia bushes for the analysis of benthic infauna (Appendix I, Table 10). The suction sampler was used instead of the coring tubes, after the tubes were found to have insufficient suction in the coarse coral-sand sediment.

Microbial Samples
         Ten discrete Lophelia colonies were sampled during dive USGS-GM-2004-03-JSL-4746 and again on dive USGS-GM-2004-03-JSL-4753.  Processing involved plating agar for bacteria and frozen DNA extractions of the microbial communities. Initial results were the cultivation of 3 vibrio colonies on a TCBS agar. Also, several of the samples from both dives yielded opaque, off-white colonies on seawater medium after incubating for approximately one week at 4ºC. This may be a monoculture, but this preliminary indicator cannot be confirmed until DNA identifications are completed.

Figure 7.  Stations sampled at the CEC 4, CEC 5, and to the south of Ludwick and Walton Pinnacles (USGS leg II).

Figure 8. Live Lophelia colonies observed in the VK 826 area, during dive USGS-GM-2004-03-JSL-4751.

Genetic Samples
       Tissue samples were taken from 36 Lophelia specimens, three black corals, two octocorals, and three squat lobster, Eumunida picta (Appendix I, Table 11). Tissue samples were preserved for DNA and RNA extraction by placement on FTA cards, and in 95% absolute alcohol, DMSO, and/or RNA later.  Photographs and dry skeleton samples (to serve as voucher specimens) were taken for most specimens. Several live specimens, taken from Kellogg's samples from dive USGS-GM-2004-03-JSL-4746, were successfully transferred to an aquarium maintained in a walk-in cooler. The microbe sampling device allows live bottom-to-surface transport of Lophelia pertusa.

Stable Isotopes
       Three hundred and seventy-five stable isotope samples were collected from flora and faunal sources during the cruise (Appendix I, Table 12). Samples were taken from 23 fish and 10 invertebrate species. Three phytoplankton and zooplankton samples were taken as well. During the cruise, multiple patches of Sargassum were sampled via dipnet. Isotope samples were taken of the leaves along with crab and shrimp species living within the algal matrix. Decaying water hyacinth was found mixed into the patches, presumably originating from the Mississippi River outflow. Additional samples were taken of this freshwater species for comparative purposes.

Paleo-ecology
       Fourteen coral samples were collected for paleo-analysis during the cruise. Samples for aging were taken from black corals, octocorals, and Lophelia (Appendix I, Table 13). Live Lophelia and rubble was also sampled for microscopic analysis (Figure 9). Additionally, several large rocks were collected (Figure 10). The rocks appear to be conglomerates of Lophelia rubble based upon external analysis and density estimates. No settled coral larvae were observed on the rock samples.

Figure 9. A fan-shaped piece of Lophelia pertusa.

Figure 10. A) Conglomerate rock containing Lophelia rubble collected during dive USGS-GM-2004-03-JSL-4752. (Insert shows Lophelia branch within rock)

Water Chemistry
       At the time of sampling, outflow from the Mississippi River had a major influence on the surface water parameters (Figures 11 & 12, Appendix II). Salinity plots display a surface water mass which is less saline with evidence of the water mass mixing to a depth of 40-50 m.  Below the 40-50 m mark, the salinity stabilizes between 35 to 36 (PSU). During most dives, bottom conditions were fairly homogeneous, however during two (USGS-GM-2004-03-JSL-4744 & 4747) of the dives, the bottom condition displayed some variance (Appendix II). For example, during dive USGS-GM-2004-03-JSL-4744 the temperature varied by 3°C, oxygen concentration varied by 0.4 ppm, and salinity varied by 0.7 PSU (Figure 12). This could be an indication of dynamic water mass exchange along the bottom topography.

Figure 11. SBE 19+ CTD data from station USGS-GM-2004-03-JSl-4755.  The freshwater lens (B), created by the Mississippi outflow, indicated mixing down to 40-50 meters.

Figure 12. SBE 19+ CTD data from station USGS-GM-2004-03-JSl-4744. The freshwater lens (B) and the fluctuation in the bottom water layer (A,B,C) are evident.

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