Beverly N. Goodman-Tchernov

Tsunami waves generated by the Santorini eruption reached Eastern Mediterranean shores

A sedimentary deposit on the continental shelf off Caesarea Maritima, Israel, is identified, dated, and attributed to tsunami waves produced during the Late Bronze Age (ca. 1630–1550 B.C.E.) eruption of Santorini, Greece. The sheet-like deposit was found as a layer as much as 40 cm thick in four cores collected from 10 to 20 m water depths. Particle-size distribution, planar bedding, shell taphoecoensis, dating (radiocarbon, optically stimulated luminescence, and pottery), and comparison of the horizon to more recent tsunamigenic layers distinguish it from normal storm and typical marine conditions across a wide (>1 km 2 ) lateral area. The presence of this deposit is evidence that tsunami waves from the Santorini eruption radiated throughout the Eastern Mediterranean Sea, affecting the coastal people living there. Dates for the tsunami deposit bracket both the so-called “high” and “low” chronology for the Santorini eruption. In addition to resolving the question of the extent of tsunami impact from the Santorini eruption, the research presented also provides a new means of discovering, identifying, and studying continuous records of paleotsunami deposits in the upper shelf coastal environment. The latter is key to understanding past events, better interpreting sedimentological records, and creating stronger models for understanding tsunami propagation, coastal management, and hazard preparation worldwide.

First Evidence for the Presence of Iron Oxidizing Zetaproteobacteria at the Levantine Continental Margins

During the 2010–2011 E/V Nautilus exploration of the Levantine basin’s sediments at the depth of 300–1300 m, densely patched orange-yellow flocculent mats were observed at various locations along the continental margin of Israel. Cores from the mat and the control locations were collected by remotely operated vehicle system (ROV) operated by the E/V Nautilus team. Microscopic observation and phylogenetic analysis of microbial 16S and 23S rRNA gene sequences indicated the presence of zetaproteobacterial stalk forming Mariprofundus spp. – like prokaryotes in the mats. Bacterial tag-encoded FLX amplicon pyrosequencing determined that zetaproteobacterial populations were a dominant fraction of microbial community in the biofilm. We show for the first time that zetaproteobacterial may thrive at the continental margins, regardless of crustal iron supply, indicating significant fluxes of ferrous iron to the sediment-water interface. In light of this discovery, we discuss the potential bioavailability of sediment-water interface iron for organisms in the overlying water column.

Hydrocarbon-related microbial processes in the deep sediments of the Eastern Mediterranean Levantine Basin

During the 2011 exploration season of the EV Nautilus in the Mediterranean Sea, we conducted a multidisciplinary study, aimed at exploring the microbial populations below the sediment-water interface (SWI) in the hydrocarbon-rich environments of the Levantine basin. Two c. 1000-m-deep locations were sampled: sediments fueled by methane seepage at the toe of the Palmachim disturbance and a patch of euxinic sediment with high sulfide and methane content offshore Acre, enriched by hydrocarbon from an unknown source. We describe the composition of the microbial population in the top 5 cm of the sediment with 1 cm resolution, accompanied by measurements of methane and sulfate concentrations, and the isotopic composition of this methane and sulfate (δ¹³C(CH₄), δ¹⁸O(SO₄), and δ³⁴S(SO₄)). Our geochemical and microbiological results indicate the presence of the anaerobic methane oxidation (AOM) coupled to bacterial sulfate reduction (BSR). We show that complex methane and sulfur metabolizing microbial populations are present in both locations, although their community structure and metabolic preferences differ due to potential variation in the hydrocarbon source.

Tsunamis and the port of Caesarea Maritima over the 'longue durée': a geoarchaeological perspective

the textual sources on which such catalogues are based remain frustratingly vague. Even where the texts do consent to identify discrete tsunamis, they rarely allow any assessment of the magnitude of these events in anything but the vaguest of qualitative terms. If a more complete record of historical tsunamis is to be achieved, alternative sources of empirical data must be developed to provide a physical corollary to the textual accounts.