The Ocean Bottom Sensors (OBS) that we deploy and recover are located in a variety of ocean depths and conditions. These seismometers were at depths ranging from 126 to 2717 meters deep. There is no light there and the pressure at this depth exceeds 3969 pounds per inch! Even in these extreme conditions, organisms exist that are able to find and attach to the OBS. In fact, the Cascadia Initiative provides a unique opportunity to study these organisms. Not only do we know the exact depths and location of each deployment, but we also know how long they have been submerged. The longer these platforms are underwater, the more opportunity fouling organisms have to settle and attach.
This environment is difficult and expensive to study. Some of the seismometers are sitting on hard surfaces while others on in soft sediment. Different ocean bottoms generally support different types of life.
Cascadia Initiative also provides the opportunity for longitudinal studies. Such comparisons over time of different deployments and recoveries at the same location could tell us something about the life history of these organisms, or even how this deep sea environment is changing.
Before leaving port, I was contacted by four teachers who were interested in having their classes participate in a real-time conversation with researchers at sea. While ashore, we were able to confirm our Skype connections using local wireless networks. Lincoln County School District (LCSD) provided a Skype-ready laptop for Crestview School’s use. Waldport High School scheduled a period to bring a science class over for a live question and answer session with researchers on the Oceanus. Each teacher solicited questions from their students regarding our shipboard research that I consequently shared with my shipmates for their assistance with the Skype interviews. Pat Kight updated this blog for educators to share with their classes.
I made three attempts on May 29th to use RV Oceanus’s Skype capabilities to connect with these schools. Unfortunately, both the audio and visual reception/transmission was abysmal. The video images were pixelated and the audio was choppy and incomplete. We achieved limited success with the high school students by the teacher repeating the students’ questions while I texted back the replies, though this process was clumsy and difficult to maintain.
To confirm that the source of our problems wasn’t with LCSD’s computer, I Skyped with a teacher and the IT person from Childpeace Montessori in Portland. We tried turning off both camera feeds, but unfortunately, the audio difficulties persisted. After consulting with Oceanus’s Maritech Erik Arnesen, I learned that our shipboard bandwidth is 193 kb input and 64 kb out. Obviously this is inadequate. Future Skype success will require sharing bandwidth from other research vessels. Coordination between the vessels operations and class time scheduling will need to be reconciled.
I contacted the educators and offered to respond to their students’ questions through this blog. When I return to shore, I will be able to address their follow up questions by Skype from HMSC.
Why did you feel you wanted to do this as a job? What got you interested in seismometers/ the work that you do? I have been interested in the ocean and marine biology since middle school in Florida. Sometimes however, you need to enter a field of study through a side door. I collaborate with geologists who study plate tectonics to communicate their research to schools and the general public.
How many years have you been a part of the Cascade Initiative? This is my fourth year working with the Cascade Initiative.
What do you enjoy most about your job? Least? Do you have a favorite project that you’ve worked on? I most enjoy working with graduate students doing research and going to sea. Writing grants and reports are a necessary evil. But twice I have had the opportunity to travel to Antarctica to help deploy and recover hydrophones to listen for earthquakes and whales.
What is the largest and oldest tectonic plate?
Finding the largest, oldest tectonic plate is a very tricky question! The reason this question is so tricky is that plates move slowly over time, breaking up into smaller plates or growing into larger ones. There can be very big plates that are very old, but because they may be completely subducted- we have very little or no way of knowing these plates ever existed! However the oldest tectonic plate that we can still observe is likely a small piece of the North American plate, located in Canada. What scientists have observed in parts of Canada are many small and very old (Pre-Cambrian) micro-plates. Over time these plates accrete together into the larger plate that we see today.
There are a few larger tectonic plates that we can observe today- such as the Eurasian and Pacific plates. The Eurasian plate spans across most of Asia and Europe. The Pacific plate spans almost all of the Pacific Ocean. However, there are many traces of past plates that have almost fully subducted, that could have been bigger- we just don’t have a good way to reconstruct their sizes yet. -Amy
Left at 12:30 with partly cloudy skies in about 20 knots of wind. We arrived at the first recovery location just after 4:00. An acoustic signal is sent down 355 meters to where the seismometer has been resting on the ocean floor for just under a year. This wakes up its receiver and the transponder sends back a signal to acknowledge our arrival. We send down a different signal to burn through a nichrome wire, releasing the seismometer from its anchor. The seismometer takes about 10 minutes to reach the surface from this depth.
We had to make several passes on the floating instrument, in order to be close enough to the Oceanus to attach the tag line. Another line was used to attach the seismometer to the crane, while a third tag line was attached to keep it from striking our hull. The seismometer was lifted and secured to the deck. We were underway to our next deployment by 5:30.
Poor Internet connections prevented Bill from live-blogging the 2013 cruise, though he was able to capture some video (below) that provides an idea of what working conditions can be like at sea. You can learn about the season’s objectives and accomplishments on the Cascadia Initiative 2013 Cruise page.
The Cascadia Initiative is an onshore-offshore seismic and geodetic experiment, using an underwater array of seismometers to measure the deformation of the Juan de Fuca and Gorda plates. The seismometers, located off the coasts of California, Oregon, Washington and Vancouver Island, need to be recovered and deployed every year in order to collect the data they contain.
Since 2011, Bill Hanshumaker, Oregon Sea Grant’s marine public educator at OSU’s Hatfield Marine Science Visitor Center in Newport, OR, has participated in the annual cruises as a means of bringing the experience of at-sea ocean research to classrooms on the shore.
For 2014, Dr. Hanshumaker is planning live Skype-to-shore sessions with selected science classrooms – if satellite Internet connections permit.
Learn more about the Cascadia Initiative from their Website.
The weather today cooperated with the successful recovery of three of our deepest deployed Abalone seismometers. The seas were calm, with 3 to 6 foot swells. The wind was out of the north, picking up to 11 knots as evening approached.
The depth of the seismometers’ deployment directly effects their recovery time. After an acoustic signal from the New Horizon is sent down to the Abalone’s release wire, we wait 7 to 8 minutes for the wire to burn through. We actively range on the Abalone as it ascents. Since the ship is stationary, the amount of time for the acoustic signal to travel up from the seismometer steadily decreases. The three Abalones that we recovered today (J43, J44 and J36) were deployed in depths ranging from 2654 meters to 2821 meters. The deepest seismometer (J36) that was signaled at 21:26, didn’t reach the surface until 22:10, and required a 44-minute ascent time. About twenty feet from the surface, a pressure-activated strobe is activated. There is also an orange flag on top of each Abalone, but since this particular recovery was at night, we relied on the strobe in order to navigate the ship into close proximity.
Once sighted and illuminated by spotlight, the New Horizon maneuvers to bring the Abalone along its starboard side. This is a delicate procedure, requiring a slow forward speed and bow thrusters so that we can bring the ship close enough to attach a tag line to the top of the Abalone.
One of us uses a telescoping pole with detachable grab hook attached to the tag line. Given the roll of the ship, large ocean swells and the vertical bobbing of the Abalone, this procedure can be very challenging. If we are unsuccessful, the New Horizon must turn into the sea for another attempt.
Once the first tag line is attached, another line from a telescoping pole and detachable grab hook is attached to the Abalone. The other end of this line is connected to the deck crane, which does the heavy lifting. Even after leaving the 300-pound weight on the ocean floor, the Abalone weighs over 550 pounds.
Immediately after the crane lifts the Abalone from the sea surface, another tag line is attached to its bottom. By maintaining tension with the first and third lines, the Abalone is prevented from colliding with the ship. The crane continues to lift, then turn aft, positioning the seismometer of the deck. Tag line tension is eased as the crane slowly lowers the Abalone and is secured to the deck of the New Horizon.
All of the data that the seismometer collected during its months on the ocean bottom is stored in the red data logger. The data logger is removed from the Abalone and quickly taken into the ship’s science lab to begin analysis.
It’s been another full day. We recovered the Abalone seismometer J65 slightly after midnight (00:10) from 165 meters of water. After moving north, the weather deteriorated. Offshore the Washington side of the Juan de Fuca strait the winds rose to more than 35 knots, coming in from the Northwest. The seas were high and steep, but we managed to recover YiM2 at 04:45 from 139 meters.:
The darkness added to the challenge, as you might expect. We cruised on to the next Abalone recovery site, but the sea conditions were too hazardous to attempt it. Instead, we continued moving north through the heavy weather.
Attempting to sleep in conditions such as these are difficult. The pitch and roll of the New Horizon keeps you awake, in spite of exhaustion. An added hazard is being tossed from your bunk to the metal deck. I placed my survival suit under the outer side of the mattress, creating somewhat of a solid hammock. To insulate myself, I put blankets between the bulkhead and my body. Needless to say, we didn’t get much sleep:
Because of the weather and our reduced cruising speed, it took us until 13:50 to arrive at Y1M1. When we recovered this Abalone, it was covered with spiny sea stars. We recovered the fourth Abalone of the day (J73) at 17:46 from 143 meters.
Today we recovered three Abalone seismometers. The first one was Y1M5 (see chart for location) at 07:30 from 828 meters down. The second seismometer (J57) was much shallower. At only 56 meters deep, its structure was covered with barnacles, anemones and a couple of sea stars. The next seismometer (Y1M4) was recovered from 563 meters of water at 20:20.
As the day progressed, the wind and sea flatten somewhat, permitting observation of marine mammal activity. During the morning we spotted two humpback whales (Megaptera novaeangliae) lunge feeding, possibly on herring. Later (~19:30), we had the good fortune to watch a large pod (~200) of Pacific white-sided dolphins (Lagenorhynchus obliquidens) swimming with another pod (~100) of Pacific right whale dolphins (Lissodelphis borealis). They could be clearly identified by theirlack of a dorsal fin and torpedo-like breaching behavior.
Sea Grant's Bill Hanshumaker chronicles ocean research missions