NOAA Teacher at Sea
Onboard U.S. Coast Guard Vessel Healy
July 1 – 30, 2008
Mission: Bering Sea Ecosystem Survey
Geographic Region: Bering Sea, Alaska
Date: July 12, 2008
Yesterday I watched the deployment of the “Spider C40” a bottom mounted instrument mooring. Today I will spend some time with Jimmy Johnson as he builds a new mooring, from scratch, right here on the HEALY.
The entire length of this mooring is over 55 meters. But for our build a mooring experience we are only focusing on the top component of the mooring, which lies at the 10 meter mark.
Jimmy’s mooring has an ISCat, Inductive Sacrificial microCat, phew… This piece of equipment is designed for shallower depths, and works like a CTD, collecting information on the Conductivity of the water, Temperature, and Depth. This microCat is an inductive device, it uses sea water to complete a circuit (similar to a potato clock) to send the data it collects to the ISCAT logger found 11 meters lower. So what does all this mean? If seas get rough, the mooring caught in fishermen’s nets, or the ice gets too thick, Jimmy’s sacrificial mooring has a 600 lb weak link that will snap and sacrifice his creation. But there is no need to worry, all the data the device already collected has been sent to the logger at the end of the cable, safe from the unpredictable conditions close to surface. Thanks to this great design scientists are able to sample areas previously un-sampleable do to the conditions I already mentioned.
If you look carefully at the design for this mooring you will see that it includes a: -Flurometer: which measures chlorophyll (primary productivity organism) concentrations. -MicroCats (3): This measures conductivity, temperature and depth. -HOBO sensors: Temperature sensor to look at the water column and temperature changes. -ADCP: An Acoustic Doppler Current Profiler sends out a frequency, gets a return signal that has bounced off small animals and or particles that FLOAT/MOVE with the current (not swim) which can give them the speed and direction of the current.
Wow, I think my brain is tired, it took a while to understand the concept of the mooring, and then to transcribe was a challenge. Needless to say these amazing oceanic devices collect valuable data. These records are then used in scientific research papers to better explain and understand the Bering Sea Ecosystem Study, thus BEST!
**Photo of the Day:*
Saying of the Day: “Rummage Sale” From the original French, Arrimage, a rummage sale historically was when damaged cargo that could not be delivered was sold at cost, or discounted. As a source of great discounts, the present day rummage sale was originally nautical. I wonder if Jimmy ever needed a rummage sale while making a mooring aboard a sea going vessel?
FOR MY STUDENTS: Can you make up a list of the equipment we will need to make our mooring? I need to add a post script…The deployment of a mooring is not the most thrilling science I have seen on board. A lot of work, and then, well it is gone. There is though one part that is a hoot, which I really love. When the quick release is activated and the 800 lb train wheel plummets to the sea floor, the floats shoot across the surface before they are pulled under. It is great and reminds me of the movie Jaws!