2014 Workshop: Oceanography Aboard the Tommy G. Thompson

UWAB students Russell Deitrick (Astronomy) and Meg Smith (ESS) attended this year’s workshop, and reported back on their experiences:

Students outside, in front of the Thompson’s bridge, enjoying the fresh air and scenic views.

On a Thursday morning in mid October, twenty-three astrobiologists boarded the Thomas G. Thompson research vessel, braving the rain as we walked to the ship from our cars. Our first hours on the ship were filled with logistics. We heard a safety briefing, became acquainted with the ship, and watched Seattle as it disappeared behind us.

The partial solar eclipse near maximum.

Our departure happened to coincide with a partial solar eclipse. Astronomy graduate student, Brett Morris, came prepared with sun-viewing glasses that let us see the eclipse safely. As we looked through the glasses, we began to appreciate the fact that we were watching the Sun while floating on the water. The Sun and liquid water are two things that make Earth a viable place for life.

This year’s Astrobiology workshop was focused on the discipline of oceanography. Its science themes are described below.

Students helped lower and raise the CTD.

Water: Jan Newton and Rachel Vander Giessen, oceanographers with the Applied Physics Lab (APL) at UW, enlisted the astrobiology students to help take water samples from a CTD (conductivity-temperature-depth) instrument. The instrument itself, called a “rosette”, consists of a circular frame about a meter in diameter and 24 cylinders that can be closed at different depths to enclose a small volume of water. This allows for measurement of the chlorophyll, nutrient, and dissolved oxygen content as a function of depth. Jan, Rachel, and their collaborators use the CTD to monitor the properties of the Sound in hopes of distinguishing natural variations, such as the salt-water intrusion—a seasonal flow of salty, oxygen-poor Pacific seawater that enters the Sound at depth, and the contribution of human activities.

Astrobiology students filtering the water samples from the CTD. From left to right: Matt Koehler, Eddie Schwieterman, and Osa Igbinosun.

Our science PI, Jody Deming, and colleagues from UW Oceanography (including Shelly Carpenter) showed us our water samples under the microscope. In just a drop of water was a world almost more vibrant than our own. To get a better understanding of the diversity in the water, we attempted to culture the water samples. These hadn’t produced visible microbial colonies by the end of our voyage, but we hope to see the results in the near future—astrobiology in progress!

Bringing in a box core.

Sediment: An oceanographer samples ocean floor sediments using a box corer. It consists of a large metal A-shaped frame about the height of a person, an open metal box that will contain the sediments, and a pivoting spade. The instrument allows scientists to scoop up sediments while preserving their layering.During the cruise, we took 3 box core samples of the sediment in the Puget Sound and Pacific Ocean. Sediment, we saw, was the real goldmine of life in the ocean. Although we couldn’t see the microbes, we could smell them—hydrogen sulfide (a rotten egg smell) assaulted our nostrils as we raised the first core, taken near a “methane seep” site at the mouth of the Sound. The sediment there is rich in methane, which leaks out into the ocean. Alarmingly, the output of these seeps is increasing as the ocean bottom water warms.

One exciting find appeared in a core taken offshore from Ballard in Seattle—a sea cucumber! This reminded us that although most astrobiologists think about searching for small life, large life could be there.

Science PI Jody Deming explains the amazing sea cucumber.

Technology: It was simply amazing to see the variety of technology that is used to do oceanography on a mobile platform. We saw microscopes that one can move by hand, a CTD that you can climb on, and a 20-ft tall buoy that collects information about the state of the ocean. But probably the most incredible technology on board is the multi-beam sonar instrument used to map the seafloor and find methane seeps. UW Oceanography’s Brendan Philip, the resident expert on the machine, explained its use. As the ship sails along, this instrument emits acoustic waves to measure the depth of seafloor features (“bathymetry”) at each position, creating a 2 dimensional map of the ocean floor in much less time than ever before. There is an unexpected political element at work here—many marine borders between nations are defined by ocean floor features whose locations are poorly determined and sometimes disputed. This technology permanently settle these disputes.

The crew recovering the Cha Ba mooring buoy, which is equipped with a communications system. The underside is covered in barnacles, which will need to be cleaned off.

On Friday, the crew recovered two “moorings” from the continental shelf just west of the Olympic Peninsula. These moorings, as John Mickett (also from APL) explained, each consist of a buoy, an anchor, and a cable extending 100 meters below the surface and lined with instruments performing various measurements. One of the moorings, Cha Ba, has a communication system on top of the buoy that relays data back to the University, but some data cannot be broadcast, so the mooring must be recovered periodically. The continental shelf is the most biologically active region of the ocean, and these moorings were placed to gather data necessary to understand these ecosystems.

It became clear to us at the end of it all—when we eventually send humans to another planet to do astrobiological research, we’ll need lots of equipment. On top of that, we’ll need to spend a large effort to sterilize that equipment. Doing astrobiology on other planets (let alone our own planet) is, and will continue to be, a difficult effort. But it will be worth it to find life elsewhere. And even if we don’t, it’s worth it to do the search and find what is out there.

Miscellaneous life: Just for fun, we compiled a list of the macroscopic life we observed on our 3-day voyage:

  • Birds
  • A sun fish, which floats on its side while basking in sunlight near the surface
  • Fluorescent jelly fish, which appeared at night as glowing blue orbs in the ship’s wake
  • Barnacles—these tubeworms literally covered the underside of the two buoys
  • Orcas—we saw the dorsal fins of these loveable whales from a distance in Puget Sound
  • Sea cucumber—a bottom-dwelling animal that is shaped more-or-less like a cucumber, with tiny appendages surrounding its mouth
Baby barnacle attached to the underbelly of the recovered mooring

To conclude, one thing is for sure: Earth is teeming with life, and we sure hope that there are other planets like ours. Thanks to all those from UW Oceanography, Astrobiology, and the Thomas G. Thompson research vessel that helped with our adventure to sea.