The graph shows in situ measurements of sulfide, silicate, oxygen and temperature as a sensor is passed from seawater into a hydrothermal vent on the Galapagos Rift at 2200 m depth and then removed again. The probe traversese a distance of about 1 m (Johnson, K. S., C. L. Beehler, C. M. Sakamoto-Arnold and J. J. Childress. 1986. In situ measurements of chemical distributions in a deep-sea hydrothermal vent field. Science, 231, 1139-1141)