Push cores were collected by the ROV Jason II on dive J2-773 on 11-April-2014.

Pore waters were extracted in a cold room at 4C using acid-rinsed, washed and dried rhizomes. The first 2 ml of fluid was discarded, then the remaining fluid was filtered through a 0.45 micron membrane and stored in hot acid (60C) washed high-density polyethylene bottles. Fluids were analyzed by electrode (pH), titration (chlorinate, calcium, and alkalinity), colorimetric (nitrate), inductively coupled optical emission spectroscopy (ICPOES), and inductively coupled mass spectroscopy (ICPMS). Precision was generally 0.2% for chlorinate and calcium titrations, 2% for alkalinity titrations, 0.01  for pH, 5% for nitrate determinations, 2% for ICPOES measurements and 5% for ICPMS measurements. All measurements were above detection limits with the exception of Mn (0.1 umol/kg) and Fe (0.01 mol/kg).

Careful consideration of these data should examine the potential of sampling artifacts for many of the solutes. We believe, for example, the Ca difference from bottom seawater values is an artifact of sample handling, resulting from the movement of sediment with carbonate present to the ship where the sediment was handled. Other solutes are likewise probably affected.