Byzantium Beneath the Black Sea

This poster reports on the August 2007 Black Sea Expedition of the Institute for Archaeological Oceanography at the University of Rhode Island (IAO) and the Institute for Exploration (IFE), in collaboration with the Department of the Underwater Heritage of Ukraine. This year’s work marks a new phase in a multi-year (2000–2012) archaeological and oceanographic survey of the Black Sea. 2007 fieldwork focuses on two Byzantine shipwrecks. The 10th century C.E. shipwreck Chersonesos A (discovered in 2006) lies at 140 m depth in the suboxic zone off the Crimean peninsula. The ship carried a cargo of one-handled jars of a widely distributed but sparsely documented local type. The sixth century C.E. shipwreck Sinop D (discovered in 2000) lies at 325 m depth off Sinop, Turkey, in the anoxic zone, and also carried a locally-made amphora type. Sinop D is the best-preserved ancient ship yet discovered in the deep sea, and non-intrusive examination of the hull yields unique information about ancient ship construction and local patterns of technological exchange. Our initial studies focus on environmental characterization and the deepwater implementation of long-term site monitoring, decay rate testing, and sediment analyses, to develop management plans for each shipwreck. Cross-site comparisons address deepwater preservation under differing levels of oxygen depletion. We conclude with an assessment of our ability to record, excavate, monitor, and conserve deepwater sites as underwater museums using remote operated vehicle (ROV) deployed technology

Co2 degassing from hydrothermal vents at kolumbo submarine volcano, greece, and the accumulation of acidic crater water

Discharge of volcanic gases in the marine environment can lead to local perturbations in ocean acidity, with consequences for biological communities and the potential for hazards related to depressurization and release of gases at the surface. Numerous hydrothermal vents in the crater of Kolumbo submarine volcano (Aegean Sea) are discharging virtually pure gaseous CO2 together with clear fluids at temperatures up to 220 °C. Acoustic imaging of the ascending bubbles suggests that the gas is being dissolved into seawater within ~10 m above the crater floor (500 m below sea level). Dissolution of the gas likely causes local increases in water density that result in sequestration of CO2 within the enclosed crater, and the accumulation of acidic seawater. Lack of macrofauna at the Kolumbo hydrothermal vents, occurrence of carbonate-poor sediment in the crater, and pH values as low as 5.0 in recovered water samples point to acidic conditions within the crater. Buildup of CO2-rich water in the bowl-shaped crater of Kolumbo may be producing conditions analogous to some African volcanic lakes (Lake Monoun and Lake Nyos, Cameroon) where overturn of gas-rich bottom waters led to abrupt releases of CO2 at the surface. A minimum estimate of 2.0 × 105 m3 (STP) of excess CO2 may currently exist in the bottom 10 m of the Kolumbo crater. © 2013 Geological Society of America