Super Samplers

A bout of bad weather and rough seas kept Jason dry for two days until conditions improved early this morning. Even though the vehicle was at rest, the science team had plenty to do to keep busy. 

CTD cast

With seas too rough for Jason dives, the science team was still able to map the area with the ship’s multi-beam system and were still able to launch three successful CTD’s (conductivity, temperature, depth), with plenty of sampling equipment attached. 

As mentioned in a previous post, the Plume Team is interested in collecting samples of particles and chemicals from various heights above the vent. With Jason on house arrest, the Plume Team fitted their SUPR (SUspended Particle Rosette) Sampler to the CTD to collect samples from the water column. Atlantis is able to park directly above plume sites thanks to the meticulous mapping done by the Jason team. 

Vent fluid sample

Chip Breier, the lead engineer of the Plume Team’s project, designed and built all of the samplers. There are three instruments, each composed of a 14-channel sampling system and each with a different purpose: the Microbiology Sampler, the Geochemistry Sampler and the Carbon Sampler. Although each collects material in a similar fashion (sucking in fluids through a tube) three separate devices are necessary due to differences in the way each sample is analyzed. For example, to measure carbon, you must combust your sample to measure the carbon dioxide released, so you need a filter able to withstand combustion. On the other hand, you need a carbon-based filter to collect microorganisms, and a polycarbonate (plastic) filter to collect minerals for geochemical measurements. 

Sara Bennett

Sara Bennett, a post-doc at NASA’s Jet Propulsion Lab (JPL), is using a pre-combusted glass filter to measure both solid and dissolved carbon in the plume. She is interested in how carbon is cycled through vent systems and is working with Dr. Max Coleman from JPL who is also onboard. It is important to study the state of carbon as it exits the vent and how carbon is altered through the food chain. “We’re looking at the whole carbon cycle, from abiotic carbon production deep within the crust, to biotic carbon production through chemosynthesis,” said Sarah. “If hydrothermal systems were to exist on Europa, it’s studies like this that may help us to calculate the biomass that may exist” Sarah says. 

Greg Dick

Greg Dick, from the University of Michigan’s Department of Earth and Environmental Sciences Geomicrobiology Lab, is interested in the microbiology associated with vent sites. He will be analyzing the SUPR Sampler’s filters to extract DNA and RNA of these very tiny microbes. “From these samples we can reconstruct the genomes in the organisms, which will tell us what organisms are there, their physiology, how they live and how they get their energy,” said Greg. 

However, enzymes very easily destroy RNA, so the samples must be treated with an enzyme-killer called “RNA later.” It is important to understand the genetics of these microbes, but it is also important to know which genes the microbes are using to survive in these conditions. The RNA tells Greg what genes they are expressing at the moment they were collected. 

Chip optimized the third sampler out of his and Brandy Toner’s interest in the mineralogy of the vent plume and, more specifically, what valance states the minerals are in at different heights above the plume. From this, they can begin to understand how much energy is available for microbes in different parts of the plume. Brandy will take these samples to a synchrotron facility to study them with x-ray spectroscopy. “Because of the way these samples are collected, preserved and analyzed, there is very low impact,” said Brandy. 

Brandy Toner (right)

As you can imagine, the Plume Team brought on board massive amounts of lab equipment dedicated preserving each sample and minimizing exposure to the environment.  So far they’ve collected about 50 samples that are currently preserved at -70º C.

From measuring the microbiology, geochemistry, and carbon from the highest energy source (at the vent) towards the lowest (near the surface) the Plume Team hopes to gain insight of who’s eating what and where, and what that tells us about the bigger picture of life in the ocean This team has been working around the clock and all of their hard work will surely extend our sphere of knowledge about the life and chemistry of the ocean. The Gordon and Betty Moore Foundation are funding their work, and we all look forward to their results!