@Sea - Skeletal Remains

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	SKELETAL REMAINS ON THE SLOPE & SHELF Personnel at Lee Stocking Island: Dr. Eric Powell, Rutgers University • SSETI founder Dr. Karla Parsons-Hubbard, Oberlin College • Encrusting organisms, esp. Bryozoa Dr. Sally Walker, University of Georgia • Encrusting organisms, esp. forams • Tethered shell experiments Dr. Carlton Brett, University of Cincinnati • Encrusting organisms Dr. George Staff, Austin Community College • Physical taphonomy Dr. Russell Callender, NOAA • Physical taphonomy Dr. Dennis Hubbard, Oberlin College • logistical assistance, videography Dr. Bill Kiene, Smithsonian Institution • Boring organisms Graduate students: Rich Krause, University of Cincinnati Emily Rose, University of Georgia Tom Jones, Texas A&M University Undergraduate student: Rebekah Shepard, Oberlin College Technicians: Kathy Alcox, Rutgers Allison Bonner, Rutgers Personnel in the Gulf of Mexico: Dr. Eric Powell, Rutgers University • SSETI founder Dr. Karla Parsons-Hubbard, Oberlin College • Encrusting organisms, esp. Bryozoa Dr. Sally Walker, University of Georgia • Encrusting organisms, esp. forams • Tethered shell experiments Dr. Carlton Brett, University of Cincinnati • Encrusting organisms Dr. George Staff, Austin Community College • Physical taphonomy Dr. Russell Callender, NOAA • Physical taphonomy Dr. Anne Raymond, Texas A & M University • Paleobotanist, wood specialist Dr. Gil Rowe, Texas A & M Univeristy • Sediment geochemistry Dr. Wei-Jun Cai, University of Georgia • Sediment geochemistry Graduate students: Rich Krause, University of Cincinnati Jocelyn Sessa, University of Cincinnati Vanese Flood, University of Georgia Cliff Nunnely, Texas A & M University Gayle Levy, University of Georgia Yang Chen, University of Georgia Undergraduate students: Rebekah Shepard, Oberlin College Jim Altieri, Oberlin College Technicians: Kathy Alcox, Rutgers University Meagan Cummings, Rutgers University This is a joint-sponsored (funded) project by National Undersea Research Center at UNC-Wilmington (Eric Powell), the National Science Foundation (Karla Parsons-Hubbard), and the Petroleum Research Fund (Wei-Jun Cai). OBJECTIVES: Fossils give us a window into the past where long-extinct animals and plants lived in environments that may no longer exist. The relationship between living things and the ecosystem in which they live is greatly intertwined. We have begun to understand these relationships for the modern world, but looking back into the past is much more difficult. Paleontologists look at the remains of ancient life, but what remains to look at is often quite altered from the original animal. Taphonomy, the study of the process of fossilization, has clarified some of the signs that tell us how that animal went from a living thing through decay and burial, to a fossil. The processes that preserve (and alter) the carcass also give us insights into the environment in which the animal lived. As the concern over long-term changes in modern marine communities continues to increase, the importance of understanding the recent history of such marine communities as cold-seep communities, shelf and slope communities near sites of oil and gas exploration, and estuarine communities becomes increasingly important. Interestingly, the principle tool available to reconstruct recent community history is the same one available to the paleontologists, namely using the skeletal remains of animals that have died to reconstruct the communities of the past. The accuracy of that reconstruction is directly dependent on the thoroughness of our understanding of the processes of preservation and decay. METHODS: In order to study these processes the Shelf and Slope Experimental Taphonomy Initiative (SSETI) deployed batches of mollusks, crabs, sea urchins, and woods in the Gulf of Mexico and the Bahamas at a wide variety of depths and bottom conditions. Experiments were deployed in the Gulf of Mexico at seven different locations representing a variety of different environments and depths in 1993. Experiments were recovered from these locations in 1995 and an additional location was deployed at that time. The experiments will have been deployed for eight years in 2001. They are at a critical juncture in the decay process as shown by our six-year recoveries in the Bahamas collected in 1999. Upon recovery, the science team immediately analyzes the samples. We run each shell, urchin, crab, and wood sample through a protocol to quantify the amount of dissolution, breakage, abrasion, biont infestation and borings present on each shell. The laboratory analysis occurs on board ship. It is critical that these data are taken while the specimens are fresh. The volume of samples processed during our 1995 mission was considerable. Each site will yield a sample set composed of a PVC pipe strung with four mesh bags. There are two bags containing 15 clams and 10 snails each. One bag contains three sea urchins and two crabs. A fourth bag contains six different wood species. Each of the eight locations are subdivided into a number of sub-environments, so up to 6 separate recoveries may be required at any one location. Experimental taphonomy is a branch of paleontology that sets out controlled experiments to measure modern processes of decay, alteration, and burial in order to better understand taphonomic processes. The more we know about how these different factors alter organisms today, the better we can reconstruct processes, and therefore environments, of the past. Experimental taphonomy is a fairly recent field of science. Most work to date has focused on easily accessible environments such as shallow water, close to shore, and terrestrial. The SSETI program is unique in its scope. The offshore continental shelf and slope is the target of this initiative. These areas are the most likely to yield fossil assemblages, yet they are the least studied because they are not easily accessed. PROGRAM: Most experimental taphonomy studies rarely exceed 1 year whereas taphonomic processes continue for a much longer period of time after the animal dies. Thus, SSETI is designed as a 10+ year experiment at multiple sites. In order to maximize the scope of this project, many kinds of data are collected from each experiment. A wide range of organism types including wood, mollusks (clams, mussels and snails), sea urchins, and crabs have been deployed at each site. Because of the variety of organisms put out on the ocean floor, the project requires scientists with many different backgrounds in both biology and paleontology. In addition, SSETI includes specialists in ocean floor chemistry to document the chemical conditions at each site. The working group therefore includes scientists from six different universities and government agencies. In addition to these principal scientists, graduate students from each of the universities have also been involved. STATUS: The SSETI goal is to continue to make collections from the sites at 5-year intervals over an additional 10 to 20 years. It is this long-term nature of the project that is critical to the understanding of rates of fossilization. In the first two years of recovery, not a single SSETI experimental site has been lost. Every retrieval effort has been successful. This is a crucial test of the SSETI design, and indicates that long-term experiments can be conducted successfully by submersible in a wide variety of habitats in the marine realm. To date, over 3000 individual skeletal remains (bivalves, gastropods, urchins, crabs, and wood) have been recovered for laboratory analysis of the taphonomic process. FUNDING: SSETI is a bold project with sites spread all over the western Gulf of Mexico continental shelf and slope in water as deep as 700 m, as well as sites from nearshore shallow water in the Bahamas down to 350 m. The majority of these sites can only be accessed by submersible. Funding for the project has been obtained by NOAA's NURP operations at the University of North Carolina Wilmington and at the Caribbean Marine Research Center. Submersibles used have included the JOHNSON-SEA-LINK, the Clelia, and the Nekton Gamma. This mission is made possible through a grant from from the National Oceanic and Atmospheric Administration as part of the National Undersea Research Program (NURP) and the National Science Foundation.