Samples were collected by push cores along a transect from the hottest part of the venting area towards the unaffected, colder sediments, i.e., at 0 cm, 50 cm, 100 cm, 150 cm, 200 cm, and 300 cm. On shore, the push cores were sliced in 2 cm intervals, frozen on dry ice, and subsequently stored at -80ºC. DNA was extracted using a commercially available extraction kit. We were able to successfully sequence 16S rRNA amplicons for Bacteria and Archaea from a total of 26 samples. Sequence data are currently being analyzed and will be deposited in GenBank prior to publication and will be made available to the scientific community. For TOC and TON analyses, dried sediment samples were weighed into methanol rinsed silver boats (4 x 6 mm, Costech). 96 well glass plates (combusted 4 hrs @ 450C) holding these samples were placed in a vacuum desiccator that also contained an open dish with about 50 ml fresh, concentrated (12N) HCl. An inverted crystallization dish was placed over the samples to protect them from water that can condense and rain down from the desiccator top during heating. The desiccator was closed and pumped out with an air driven aspirator, to a reading of about ~0.5 atm and the desiccator is placed in an oven kept between 60 and 65 C. Acidification was allowed to run for 60 to 72 hours. The samples were then transferred to another vacuum desiccator, this time charged with indicating silica gel (Fisher S162-500, activated by heating to 450ºC overnight, and pumped down again and dried for about 24 hours before use. Immediately before analysis, samples are wrapped in tin boats (Costech, 4x6, methanol rinsed).