Copy! Stand by!

by Natalie Zielinski

Since setting sail on Monday July 3rd, the other students and myself have done our best to settle into our daily 12 hr shift routines. We were each hired on as a Conductivity Temperature Depth (CTD) Watch Stander with the responsibility of preparing the CTD rosette (see photo below) in the Baltic Room before each cast, monitoring its decent to the ocean depth, closing Nisken bottles to trap water on the ascent, and collecting samples after the cast. If that doesn't sound exciting enough, we each have also been given additional responsibilities! For me, I have the honor in helping run the Lowered Acoustic Current Doppler Profiler (LADCP), an instrument attached to the CTD Rosette frame that uses the Doppler effect of sound waves to continuously measure the current velocity during the cast.

Bruce Hubert (LDEO) and Carolina Trujillo (UH) setting up the LADCPs and battery system on the CTD before the cruise. Notice the gray, vertical Nisken bottles. These are systematically closed to trap water on the ascent during each cast. So far, our deepest cast has allowed us to collect water at ~4500-m! (photo by Natalie)

There are two LADCP instruments on the CTD, one that looks upward and another that points downward. About 20 minutes before each cast, I step into the wet lab directly adjacent to the Baltic Room and begin running Unix code to initiate the 'pinging' process of the LADCPs. This may sound like a mundane job but surprisingly this entails quite a lot of attention. When the LADCPs are on the deck awaiting deployment, the instruments and stand-alone battery need to be connected to the boat's electricity through long black cables. Each connection has a strict pattern to ensure I don't electrocute myself, while also monitoring the Unix coding process. Thankfully, I have a wonderful teacher, Carolina Trujillo from the University of Hawaii, to help and guide me as I learn.

 

(image 1) The upward-looking LADCP mounted to the yellow CTD Rosette frame above the Nisken bottles, roughly 6-ft off the bottom. (image 2) The downward-looking LADCP mounted to the yellow CTD Rosette frame below the Nisken Bottles. The blue discs are the transducers. (photo by Natalie)

During the decent of the CTD rosette, I join my fellow student colleague, Rebecca Beadling from the University of Arizona, at the CTD monitor station to oversee the deployment and trigger Nisken bottles on the way up. About 4 hours later after the CTD is back on desk, depending on the bottom depth of course, I return to the wet lab to turn off the LADCPs, connect them to the ship, and download the data. In the beginning, the LADCPs were happy and running the way we expected. Then, they became temperamental and for a while they didn't connect to the computer to allow us to download the data. Carolina and I have done our best to pin point the problem, and after some long communication with technicians onshore, we have finally solved issue! Thank you Mr. Poseidon for blessing this cruise. Copy and out. 

Results from the LADCP for station #3 at 30° 4.804' S, 153° 35.990' E