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10/30/05 - Back to work, finally! |
Calmer seas off Jacksonville never materialized, so we steamed back to the Savannah Banks dive site. Six-foot swells are the cut-off for launching the Johnson-Sea-Link, and this afternoon we finally found seas below the eight- to ten-foot size we've been dealing with. For the first time in two and a half days, the sub went down.
Shortly after the sub's launch, Ilya Nikanorov, one of two engineers serving as data manager for the ship,
gave Tara Cassaza, Missy Partyka, Colleen Young, and Jennie McClain a short course on Conductivity
Temperature Depth (CTD) operations. After the sub surfaced and its treasure trove of specimens were cataloged
and secured, we deployed the CTD to get readings that will serve as another piece of
the puzzle in this small part of the ocean. The CTD consists of an underwater
unit and a drop carousel of 24 bottles (canisters), which can be fired automatically from aboard
the ship. Deployed when the ship is stationary, the CTD records temperature, conductivity, salinity,
oxygen level, difference in light penetration, flourometry (chlorophylls and dissolved organic matter), and water
pressure at the depths the canisters are fired. The Johnson-Sea-Link possesses numerous sensors, and we're not sure its pH readings are correct.
Hence, the main objective for this CTD deployment is to collect water samples from twelve different depths, (firing two canisters
per depth), check the pH at these depths, and compare these results with those obtained from the Johnson-Sea-Link.
The sub brought up some great specimens. There were many large samples of coral, a huge sea urchin with toxic
spines, several sea stars, and a squid. While the day shift worked up the samples from the sub dive, Tara, Jenny,
Colleen, and Doni retrieved water samples from the CTD. We then started running transects, using the same sonar equipment
(the Knudsen, a sub bottom profiler) from a few nights ago. The ocean profile here in the Savannah Banks is quite
different from the more level area that was mapped of the Stetson Banks. Dr. Ross says that future plans include some
three-dimensional sonar mapping which will yield an even clearer picture of the seabed.
Everyone is thrilled to be working again and a sense of normalcy has returned to the ship. We are currently headed back to Jacksonville where we will do some more sub bottom profiling in the early morning to research possible submersible deployment sites. With any luck, the Johnson-Sea-Link will go down for its first morning dive in several days.
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