The Chemist's "BEAST"

Extreme Water Sampling at an Underwater Volcano

Dave Butterfield
University of Washington

Intake nozzle on water sampler (the "Beast") coated with sulfur.

What do you think of when someone says “I’m a chemist”? Lab coats, glasses, clean laboratory, test tubes, glassware, sparkling expensive instruments? The picture out here is different. We’re working on a ship in the tropics, wearing shorts and t-shirts, getting dirty, working on deck with tools, doing plumbing on instruments, and staying up all night sampling. It’s certainly not easy, but given the choice between laboratory chemistry and being out here studying how volcanoes work, I want to be out on the ocean.

Re-heating the Beast's wand in Brimstone's vent, an attempt to remove the sulfur clogging the intake valve.

Capturing good samples at underwater volcanoes takes a different set of tools. Because I am interested in a full range of chemistry and microbiology, I developed the Hydrothermal Fluid and Particle Sampler, commonly known as “the Beast”. With an in-line temperature sensor at the tip of the titanium intake nozzle, a flexible Teflon-lined hose, 24 custom exchangeable sample containers, in-situ pH and H2S measurement, data logging, etc., the Beast is definitely more sophisticated than a titanium syringe, which used to be the standard vent sampling tool. The Beast is a great tool for studying the relation between chemistry and microbiology in the submarine hydrothermal environment because it can bring back samples for DNA analysis and culture experiments.

Dave Butterfield holding the Beast's wand after the dive. The yellow sulfur not only coated the outside, but clogged the intake of the fluid sampler.

The eruptive vent here is called Brimstone for good reason. Sulfur is abundant as SO2 gas, fine “smoke” particles, sulfuric acid, and as molten sulfur that periodically erupts in spectacular yellow bursts. While using an extra-long intake nozzle on the Beast to reach into the sulfur-rich volcanic vent at Brimstone, the nozzle got away from us and plunged down into the volcanic sands right in the eruptive vent. The result was instant clogging of the sampler as molten sulfur and tephra were sucked up the nozzle and frozen into a solid plug. In an effort to regain sampling capability, we deliberately laid the entire intake nozzle down on the hot smoking ground to try to re-melt the sulfur in the nozzle while pumping in reverse. That effort was in vain and we ended up with a sulfur-covered mess. The Beast had met its match at Brimstone. Obviously that won’t stop us and the Beast will ride again.

Jason’s manipulator arm holds a long intake tube designed to sample the hot fluids and gases coming out of the Brimstone eruptive vent. However, boiling seawater and molten sulfur make the sampling difficult.

Molten sulfur sticks to the intake tube and has clogged the fluid sampler on this dive. Fluid samples from the eruption plume were successfully collected on later dives.

All video copyright by Advanced Imaging and Visualization Lab WHOI