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Fouling Organisms on OBS

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.

egg mass
Egg mass on seismometer antenna

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.

Sea star LR
Sea Star attached to Ocean Bottom Sensor

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.

2014-05-29 seastar
Ventral surface of sea star

Life will find a Way!

squat lobsterlow
Squat lobster





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.

Questions from Springwater Environmental K-8 School’s 7th and 8th Graders

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

First day at sea

2014 Cruise Map
2014 Cruise Map

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.

A seismometer is a type of Ocean Bottom Sensor (OBS)
A seismometer is a type of Ocean Bottom Sensor (OBS)