Porewater geochemistry data for sediment samples that were included in the global seep survey conducted via Alvin dives from R/V Atlantis cruise AT15-40 in the Guaymas Basin in 2008

<p>Porewater geochemistry of Guaymas Basin hydrothermal sediments (Southern Spreading segment, 27°00.44N and 111°24.55W, 2000 m water depth) including methane, CO2, and sulfate.&nbsp;</p>

<p>During two R/V Atlantis cruises to Guaymas Basin, the association of Beggiatoa mats with hydrothermal seepage and the habitat preferences of various Beggiatoa types were investigated by geochemical and microbiological characterization of sediments underneath Beggiatoa mats in combination with temperature measurements down to 40 cm sediment depth. In particular, temperature profiles and corresponding sulfide, sulfate, dissolved inorganic carbon (DIC), delta 13C-DIC, methane, and delta 13C-methane gradients from mats exhibiting orange-to-white color transitions were examined to elucidate hydrothermal fluid delivery and/or tolerance associated with differently colored Beggiatoa types&nbsp;(McKay et al. 2012)<br />
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