Naomi Wu Blog Leg 2

August 20:

A sliver of moon peaking from the darkness.
Credit: N. Wu, University of Washington, V22

The midnight shift for today was calm. With a little down time before things got hectic, I went out on the deck for some fresh air. One thing you notice when there is down-time at night is how dark it gets outside. With ROPOS asleep on its pallet and the Rosette tucked away in the corner, there are almost no lights on.

I curled up on a deck chair with “PADO” by BIBI playing from my earphones. Looking up at the pitch-black sky, my eyes slowly adjusted to the darkness. I noticed a smudge of lighter grey in that velvety blackness. It was so peculiar and seemed to have no dimension. Suspended right in front of me just off the edge of the ship I felt like I could touch it, yet I knew it had to be far away. I stared at it dreamily, feeling myself get drowsy and questioning if I was asleep (and severely late for my shift!) Then, as a single cloud drifted away, I saw that the grey smudge had been the hidden sliver of a moon. It was surreal because it looked like a white paper cut-out of a crescent moon, suspended with some string as if it was a prop in a puppet show. I was in the audience as it was moving up and down robotically to some unheard music.

After an hour or so, we were called over to the ROPOS control lab to prepare for the next dive. Even though I had been in the lab logging a few times already, each time I entered the crowded dark lab with its dozens of bright screens, I always felt a new rush of adrenaline.

ROPOS was impressive, not only because of its complicated engineering, but because it went to depths humans could never physically reach. I began swimming competitively when I was just 3 years old, I was surfing at the age of 6, I was a lifeguard in my teens, and I earned my advance PADI certification only a year ago. Water had been my natural element, and I had never considered that there was water I would never be able to swim in. But the ~3000 meter depths we were exploring were out of bounds to human touch. The ROPOS was our only connection to that mysterious and vast blueness below our reach.

The MARUM Germany Overview Sonar at the seafloor, in need of a little troubleshooting.
UW/NSF-OOI/CSSF; Dive R2223; V22

Today’s main dive task was to troubleshoot and move a 4K camera system located at Hydrate Ridge. This technology is used by MARUM, Center for Marine Environmental Sciences located in Bremen, Germany to provide long-term survey of the methane bubble seeps, recording data to help understand what factors determine a seep’s magnitude, density, and location. Eberhard Kopiske, a research assistant from the Geosciences group at MARUM, relayed instructions from his colleagues back in Germany to the ROPOS pilot.

One issue that had occurred with the camera was that it had a blind spot of ~40 degrees in its 360-degree rotation. The camera was mounted on a platform perched on a tripod stand with a segmented track aligner that kept it steady during rotations. There were three orange arms that would lay down the track aligner as it rotated, but one arm had seemed to be slightly off where it caught on the segments causing a disruption to an otherwise smooth action. Furthermore, when rotating back to its origin, the camera would give a rather strong jolt when it was mechanically stopped, not ideal especially for its long-term usage. MARUM also wanted to move the camera to an active methane seep site as the methane seeps in that location had been suffocated by falling sediment.

Unfortunately, after a couple hours of discussion, it was realized that the maintenance fixes needed would not be possible without bringing the camera back to land. As the fixes were not crucial to its function, the camera would be left as it was. Now, it was time to look for an active methane seep to relocate to.

ROPOS explored the seafloor, passing by dozens of rockfish and seafloor pits that glimmered at their bottoms. Finally approaching a seep, the ROPOS crew stopped and admired the little stream of methane bubbles. Another seep was found a little further east. However, both active seeps found had been ~64 feet away and the 4K camera was limited by its 50-foot cable. Thus, sadly, the 4K camera would remain at its location and hopefully in the future, a methane seep would develop within its radius.

As the ROPOS began ascending, my shift ended, and I relinquished my logging station to the next shift.

August 19:

Methane bubble plumes spotted on the Thompson’s hull-mounted multi-beam plume survey at Southern Hydrate Ridge. Credit: N. Wu, University of Washington, V22.

The midnight shift was like a lucid dream. The ship was quiet with many of us sound asleep, but a consistent ghostly moan came from the ships belly. Things seemed to be hazy but there was something in the air that cleared your vision.

Jenn hustled my shift (Aisha, Jessica, and I) to the dark ROPOS lab. The control room was illuminated by the dozens of monitors installed on every table surface and wall. We watched through the ROV’s still camera and HD camera as it transited to the seafloor, taking dozens of pictures on the way down.

It’s main task for this first dive was to clean and retrieve equipment that had been left down there for a year. A bouquet of anemone had found shelter on its metal scaffolding, living harmoniously with the machine on the desolate sea floor.

When ROPOS was brought up, we assisted Julie with the rather splashy collection of her water samples for oxygen, DIC, and Chlorophyll data.

Around 3:30 PM, Mitch rushed into the main lab to call me over. I had talked to him about my interest in the methane plumes, and he had come to tell me that the survey over the Southern Hydrate Ridge had begun.

I entered the computer room with its 12 monitor Batcave set up. Eberhard explained how the multibeam was sending pings down and how they were reflected to show us the seafloor or any other objects that were lurking. Because the sound frequency of water and gas is so different, the pings that otherwise penetrated the water easily would reflect a strong signal from the hydrate-encased gas bubbles. This allowed us to easily see gas bubbles, even single gas bubbles, emanating from the ridge. This was also how we would be able to identify fish with lungs as the lungs full of air would reflect a strong frequency back!

I was given a map of the Southern Hydrate Ridge, showing the track lines we would cover. Mitch explained that the track lines ideally would overlap by at least half to allow for accuracy on the coverage data. During our turns, we would overextend to ensure we did not lose any data while we readjusted to the next line.

The seafloor bathymetry at the Southern Hydrate Ridge has a gradient from ~1,000 meters to ~800 meters, Einstein’s Grotto (our main point of interest), being at about ~800 meters.

After sitting in the computer rooms, eyes trained on the water column imagery, we finally saw a plume of methane bubbles. Like an elegant line dancing upwards, it wiggled as we moved forward turning into red dense bubbles and then dissipating.

Eberhard also noted that the bathymetric data had changed quite a bit. He had said his colleague, Yann, caught an area of sediment collapse on camera imagery, and so he expected quite a bit of morphology change in the area due to the naturally active nature of these methane seeps.

At this point, we were almost halfway through our tracks, and had seen the needed evidence of methane plumes. I retired to my quarters for a quick shower before dinner.

After dinner I went to bed, preparing for the upcoming midnight dive we would do at the ridge.

August 18

A wall of mysterious fog ahead as we stand at the bow, heading to a new adventure. Credit: N. Wu, University of Washington, V22.

After a solid breakfast of eggs and bacon, we followed our mother ducks (Andrew and Jenn) around the ship, familiarizing ourselves with the many different rooms we would be able to access: the Wet Lab, the Main Lab, the Computer Lab, Bio Lab, Freezer Rooms, and maybe the most important, the ROPOS control room. We were briefed on what resources we had and each of us began thinking of our potential projects.

I went to talk to Eberhard, a German scientist on board, about the Southern Hydrate Ridge plume survey. Reading a paper his colleague had worked on, “Variability of Natural Methane Bubble Release at Southern Hydrate Ridge,” I learned about the Southern Hydrate Ridge methane seeps that we would be visiting the next day.

Located along the peanut-shaped Hydrate Ridge are methane bubble plumes. At very shallow depths, these methane bubbles can exchange their gasses with the atmosphere, but at deeper depths they dissolve into the water column. The pattern of these ebullition events in the North Hydrate Ridge were generally determined by the tides, but in the South Hydrate Ridge, it appeared to be some other process under the sediment surface that affected the frequency and magnitude of these methane bubble plumes. Because methane is a major greenhouse gas, understanding the sinks and sources is crucial to calculating the rates of methane exchange with our atmosphere. Furthermore, knowing the origin of the methane, whether it be from geological or biological sources, would allow better understanding of our natural methane output.

The MARUM Germany Overview Sonar in its deployed state accompanied by an adorable lobate ctenophore, Bolinopsis infundibulum in the foreground. Credit: UW/NSF-OOI/WHOI, V21.

In a very simplified version, Eberhard was there to oversee the movement of equipment that had been focused on an active methane seep site when first installed back in 2018. That methane seep had been covered by sediment and was no longer active. His colleagues back in Germany had live visuals and multibeam sonar data of the seafloor and bubble plumes, but needed the equipment and camera moved to a new active site so they could continue the observation and study of the methane seeps. This began inspiring me for my own project!

Around noon, we had our first taste of life at sea, an emergency drill. All of us hobbled to the main lab with our obnoxiously bright orange immersion suites. Putting them on, we found ourselves looking like a group of radioactive Teletubbies, safe radioactive Teletubbies.

After our safety drill, the crew began their own drill with three fully dressed firemen navigating the ship to ensure a safe escape if we needed it. Although silly as it seemed at the time with the lot of us in cumbersome bright orange wetsuits, the amount of safety equipment and procedures would protect us if disaster hit, and it was a wake up call on how hazardous the equipment around us was.

At 6:00 PM on August 18th, we finally set sail. We all gathered at the bow.

There was the signature Newport Beach fog all around us, drenching us slowly but none of us cared. As we began to depart, the misty beaches at our sides dissolved behind us into the fog. A group of kids on the rocky beach frantically waved their arms in excitement, sharing our awe of the impressive Thompson leaving dock.

We all stood silently at the bow, periodically interrupted by the ship’s loud horns. A bridge passed far above us, and ahead was a wall of cool wet air. Sarah and I went to the head of the ship, sitting at the front, and as we began heading into the current, we caught air with each undulating wave.

After an hour of starring longingly into the cold waters, I went to bed to prepare for my first midnight shift, salty sea air like perfume on my skin.

Yoav arriving at the Thompson
Yoav Pinto strutting on the dock after his van got to the boat faster than Mike’s van even though he left later.
Credit: N. Wu, University of Washington, V22

August 17:

Today, after a 6-hour drive to Newport Oregon, we boarded the ship around 4:00 PM. You could feel the excitement, but also a sense of growing anxiety. As we entered the Main Lab for our brief, we passed by tables of hard-working scientists and engineers. We gazed at the complicated programs open on their sleek computers, wide eyed with premature ideas for our projects.

Gathering around the back table in the Main Lab, we listened eagerly as Andrew and Jenn began our brief. Today we would be settling down as crew finished preparing for departure. Tomorrow evening, we would begin our journey at 6:00 PM.

I took this opportunity to rest up for tomorrow’s adventure and slept like a rock from 6:30 PM to 7:30 am the next morning!