AbstractMid-Cayman Rise objectives were built on exciting results from a flurry of recent expeditions that investigated hydrothermal sites in the region (German et al., 2010, 2012). The 2013 E/V Nautilus cruise explored oceanic core complexes (OCCs), tall, smooth-sided hills that rise from the seafloor on the flanks of some mid-ocean ridges. Dives (Figure 1) explored the full extent and nature of life around the Von Damm hydrothermal field, previously discovered there, as well as the geology to further understanding of the vents’ origins, and to survey the OCC summits that had never before been investigated by a deep diving vehicle. This 2013 study was the first Nautilus cruise to have more scientists participating in the expedition from locations on shore than from the ship, tripling the size of the science party.
The immediate objective is to learn techniques of intact polar and apolar lipid analysis (IPL and AL, respectively) in the Hinrichs Lab (MARUM, Bremen, Germany). Analysis will be conducted in several sections from five sediment cores collected in a cross-shelf transect during the LARISSA 2012 research expedition in the Weddell Sea. This work would be undertaken in a three-month graduate student research exchange. The overarching research objective is to assess the changes in sedimentary microbial community structure and the input of organic matter as the Larsen A embayment (Weddell Sea) transitioned from an oligotrophic sub-ice shelf, dark system to a photosynthetic open ocean system. These changes will be verified and related to the ice shelf collapse in space and time. The results will be merged with geochemical (concentrations of methane, sulfate, sulfide, dissolved inorganic carbon, and nutrients), geological (Lead 210 dating, diatom counts and chlorophyll concentration) and genetic profiles (i.e. bacterial and archaeal 16S rDNA sequencing and metageomics data) generated by collaborators in the NSF-funded LARISSA Program.