Day 6: Veil hunters

We use Jason to sample various sites underwater. Jason ops take place around the clock during a dive as we travel to various sites marked during previous research expeditions to Lō’ihi. During the day before yesterday’s 4:00 a.m. to 8:00 a.m. watch we found some gorgeous microbial mats and structures called chimneys, where active hydrothermal venting is occurring.

The first two hours of watch were spent searching for Marker 34, near an area of the seamount known as Hiolo South. We have marker locations stored in the navigation system onboard, but it can still take hours to locate a particular site. The sites being sampled during this expedition were last visited four years ago, and it’s challenging to predict how the landscape might have changed in that time. Sites are marked with painted numbers on bucket lids, and can be difficult to spot.

Marker 34

We thought Marker 34 was an eel on the rock before we got closer!

It does say 34 if you look closely!

It does say 34 if you look closely!

Once we find a site, we mark it in our navigation system and begin sampling. At Marker 34 we took temperature measurements and electrochemistry readings at sample sites and filled our bio mat sampler.

Temperature probe.

Temperature probe.

Electrochemistry wand.

Electrochemistry sensor.

Mat samples will later be brought on board for processing on the ship. Samples are dealt out to the various lab groups onboard, who then work to culture iron oxidizers, isolate genomic DNA, view samples under the microscope, fix them in glyceraldehyde and glycerol, and perform other shipside analyses. Any remaining mat sample is frozen at -80C for future use.

We’re very excited about the mats collected at Marker 34. These were very “fluffy” iron mats growing around a ledge above venting chimneys. We call these types of mats “veils” because of their light orange color. As we sampled, the veils peeled away, revealing darker, older mat material. These Marker 34 samples will be split into two groups—those collected on the ledge face, and those collected on the underside of the ledge.

Microbial mat described as a veil, with laser pointer from Jason. Distance between the two laser markers is 10cm.

Microbial mat described as a veil, with laser pointer from Jason. Distance between the two laser markers is 10cm.

The mat sampler.

The mat sampler on one of Jason’s arms.

Here the fluffy mat has peeled back, revealing the older and less active mat material.

Here the fluffy mat has peeled back, revealing the older and less active mat material.

Depending on the needs of the science team, we’ll return to Marker 34 and other sites to pursue additional samples, photo and video site surveys, and chemical analyses. In the meantime, Jason has been having some electrical problems and our second dive was terminated several hours early in order to avoid damaging the craft and our sampling equipment. Stand by for updates as we prepare for Jason dive #673!

-Kelsey Jesser, Western Washington University

Photo credits: all photos from the Jason control van

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