What is the chemistry of Endeavour’s Hydrothermal Fluids


Withstanding the Seafloor Environment

There are many challenges to working in the deep-sea vent environment that require specialized sampling equipment. For example, samplers must be designed to withstand pressures < 200 times those we live under, temperatures up to 400°C (752F), and fluids that dissolve metals in < 1 day.


Sampling Small Amounts of Chemicals and Gases

In addition, because some of the most valuable measurements are of chemicals and gases that occur in extremely small amounts, it is also important that the instruments remain free from anything that may contaminate the samples. Because of these constraints, one of the most common materials used in the design of equipment to sample vent fluids is the metal called titanium. During this expedition, we are using two specially designed pieces of equipment to sample hydrothermal vent fluids for chemistry.


The Hydrothermal Fluid Particulate Sampler (HFPS)

The Hydrothermal Fluid Particulate Sampler (HFPS) is especially useful for sampling diffusely flowing fluids and for obtaining particulate samples of microbes that may be entrained in the vent fluids. The HFPS was built by NOAA-PMEL and is operated by David Butterfield.


Up to Fourteen Water Samples

The HFPS allows up to 14 water samples plus 10 filters to be obtained on a single dive. Check valves prevent loss of sample back to the main fluid line, and pressure relief valves allow some sample expansion during decompression. An electronic control package allows the user to control both pumps and the valve, and to display and collect temperature and flow-rate/volume data using a graphical interface on a PC.


Understanding Rock-Fluid Interactions

In concert, analyses of these fluids are critical to understanding therock-fluid interactions that occur deep within the Juan de Fuca Ridge. They will help constrain the temperatures at which rocks are altered and fluid-mineral precipitation reactions that occur within the chimneys. The fluids’ chemistry may also record the influence of microbial populations on the compositions of the fluids, and they may inform us on the compositions of fluids during formation of the early Earth.