The Dorado Outcrop is a site of focused low temperature hydrothermal venting in the East Pacific Ocean and is representative of ridge flank crust systems that are responsible for 35% of the Earth’s heat loss. Fluid is discharged at 103-104 liters per second at 10-20°C and diffuses through sediment on the outcrop, impacting temperature and geochemistry. The microbial communities on and around an active venting site of this nature have never been studied. This proposal will address this gap by surveying the microbial diversity along a sediment depth transect across the outcrop. In December 2014 cruise AT26-24 collected sediment samples from this outcrop, and DNA was extracted. 16S sequencing from 11 cores on the outcrop and one core taken near the outcrop will provide the first data about community diversity, dominant taxa, and changes in potential community function under various physiochemical conditions.</p><p>PI, Laura Zinke