Heather O’Connell: Soil Samples, Surveying and Sumdum Glacier, June 17, 2018

NOAA Teacher at Sea

Heather O’Connell

NOAA Ship Rainier

June 7 – 21, 2018

Mission: Hydrographic Survey

Geographic Area of Cruise: Seattle, Washington to Sitka, Alaska

Date: 6/17/18

Weather Data from the Bridge

Latitude and Longitude: 57°43.2’ N, 133 °35.7’ W, Sky Condition: Overcast , Visibility: 10+ nautical miles, Wind Speed: 2 knots, Sea Level Pressure: 1024.34 millibars, Sea Water Temperature: 7.2°C, Air Temperature: Dry bulb: 11.78°C, Wet bulb: 10.78°C

Science and Technology Log

I was part of the crew launched on RA-3 where I learned to turn towards a man overboard in order to ensure that the stern of the ship turns away from them. Communicating via the radio was another highlight where I was certain to follow the proper protocol.

RA- 3 Launch with Multi-beam sonar
RA- 3 Launch with Multi-beam sonar

Next, we moved onto deploying the C.T.D., conductivity, temperature and depth device to determine the sound profile of the water. The winch is a pulley system off the back of the launches that casts the C.T.D. and functions similar to a crab pot winch with an addition of a pressure bar to alleviate the weight of the thirty pound C.T.D.

Deploying the C.T.D.
Able Bodied Seaman Tyler Medley and Junior Officer Michelle Levano deploying the C.T.D.

After passing an iceberg with a seal, we began collecting soil samples with a device called a grab sampler. This was connected to the winch and went down about three hundred and thirty feet to collect a bottom sample. The first sample consisted of small shells of mostly barnacles, along with some medium grained sand and large silt submerged in solution.  The second sample was pristine clay with a slight green color created from the physical erosion of the surrounding rocks of the mountains. Soil sample data is collected and included in the data report because it can affect the sound speed of water. It can also provide useful information about the types of organisms that could live in this ecosystem, along with the types of resources available in this area.

Grab Sampler
Grab Sampler

Next, we connected with RA-6 and had a crew transfer so that I could learn how hydrographic surveying actually works. Newly certified H.I.C., hydrographer in charge, Audrey Jerauld was kind enough to share her knowledge of conducting surveying within Tracy’s Arm. Since Rainier surveyed most of the channel, RA-6 was simply collecting near shore data using the multi-beam sonar. The I.M.U., inertial measuring unit, (not to be confused with the Hawaiian imu which is an underground cooking pit) accurately records the pitch, roll, heave and yaw of the boat. This allows GPS receivers to function even when a satellite is not available. I learned that this is important since when surveying next to a steep cliff,when the satellite cannot reach the small launch, this provides an alternate, accurate means of placement. It determines a D.R., or dead reckoning based on the I.M.U. accelerators and creates a plot of where it thinks the launch is. 

deploying C.T.D.
Junior Officer ENS Collin Walker and H.S.T Audrey Jerauld deploying C.T.D.

Personal Log

The sun was shining yesterday afternoon and I loved soaking up the Vitamin D offered by the sun’s rays while practicing yoga on the flying bridge. When Junior Officer Ian Robbins invited me to go kayaking, I eagerly accepted the opportunity to explore Holkham Bay on a kayak with more maneuverability. I descended into the kayak via a rope ladder off the ship and paddled about three miles through a kelp forest to the nearby Sandy Island. Here, there were endless barnacles, urchins, starfish and kelp to explore near the shore in this inter tidal ecosystem. After pulling the kayaks up to shore and exploring land, I had the realization that with each step I was crushing more living organisms than I cared to consider. The rocks and shells soon turned to rye grass and marshland with some larger rocks.

Sunflower Star
Sunflower Star, Photo Credit: Ian Robbins
Seastar in Intertidal Zone
Seastar in Intertidal Zone

We eventually pulled the kayaks to the other side of the island and kayaked our way next to a blue iceberg. Seeing concentric circles and the intricate pattern of the frozen water crystals was a spectacular sight. Kayaking around such a beautiful natural phenomenon that has been in existence much before I have, was again, a humbling experience.

Iceberg off Sandy Island
Iceberg off Sandy Island

Paddling back to the ship with Sumdum glacier to the right and passing through a narrow channel that lead to the beautiful golden glow of the sun about to set proved to be a perfect ending to an exciting day. Feeling amazed at the sight in every direction made me once again feel extreme gratitude for this exceptional opportunity to be around such vast beauty.

Holkham Bay Sunset
Holkham Bay Sunset

Did You Know?

Mooring line, or the rope used to tie a ship to the dock, is often made of spectra. This synthetic polymer, spectra, doesn’t stretch and is extremely strong, so much so that it can bend metal if enough tension is put on it. It is three times stronger than polyester.

Leave a Reply

%d bloggers like this: