Group photo of the scientific party for The Windows to the Deep expedition. Click image for larger view.
WINDOWS TO THE DEEP: CRUISE SUMMARY
Dr. Carolyn Ruppel, Co-Chief Scientist
Associate Professor
Georgia Institute of Technology
For more details on cruise results, please see the Full Summary PDF (17 pages, 936k)
The overarching goal of the 2003 Windows to the Deep expedition was exploration of the Blake Ridge and Carolina Rise for new methane seeps and cold seep communities using an integrated biological, chemical, and geophysical approach. To this end, the expedition team included graduate students and scientists with experience in aqueous and sediment geochemistry, seep ecology, microbial ecology, hard-rock geology, seismology, geophysics, and marine hydrogeology. Following highly successful explorations of the Blake Ridge Diapir methane seep community using the R/V Atlantis and DSV Alvin during a 2001 NOAA/NURP sponsored cruise led by Windows to the Deep co-chief scientist Cindy Van Dover, the region held promise as an excellent target for the discovery of similar seeps.
This summary provides greater detail about the expedition and its findings through the prism of both synthesis studies and focused, specialty studies. In general, the contributions of the expedition can be summarized under three major headings: Geology, Geochemistry, and Biology.
Windows to the Deep provided the following contributions to our geological knowledge:
- The most complete and detailed map ever assembled of the important Cape Fear submarine slide
- Structural control on seafloor seeps and a pseudo-3-dimensional image of the Blake Ridge diapir
- Groundtruthing that tested the hypothesis of active methane seepage in the Blake Ridge depression
- Representative rock samples from a variety of settings within the study area
- Dating of sediments exposed on the northeastern flank of the Blake Ridge
Samples obtained during the Alvin dives will contribute to knowledge of the seep community ecology and seep microbiology. These contributions will include:
- Distribution of clam and mussel communities with respect to seep chemistry, location, and “vigor”
- Continuing histological and new ultrastructural studies of a pathogenic parasite of mussels, building on the knowledge from the 2001 expedition
- Studies of worms in tubes, ice shrimp, and other species and identification of possible new species
- Vesicomyid clam reproduction studies and links to sediment geochemistry
- Vesicomyid clam parasite studies
- DNA analysis of thiotrophs
- Microbial community analysis of bacterial mats and sediments associated with mussels, clams, and methane seeps and comparison to seep sites in the Gulf of Mexico and other locations
The primary contributions from the geochemical studies will include:
- Sulfate and sulfide concentrations for use in understanding biogeochemical processes
- Stable sulfur isotope measurements of sediment pore waters
- Carbon isotopic analyses of authigenic carbonate
- Sediment CHN and grain size analysis
- Sediment redox profiles
- Sediment total sulfur analyses
