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Sampling the water column is also important

June 8, 2011
Credit to DeepWater Canyons Expedition

Figure 1. Example graphs of one of our CTD stations near Baltimore Canyon.

As part of our cruise activities we collect various physical and chemical data about the water column.  An instrument called a CTD (conductivity-temperature-depth) is used to get sound velocity profiles which are used to help make our multibeam sonar data more accurate.  In addition to sound velocity, this instrument also measures temperature, depth, salinity, dissolved oxygen, pH, and turbidity from the surface to as near the bottom as we can lower.  An example of these data from our last cast is presented in Figure 1.  We take these casts about every 6 hours, and on some casts we also take water samples for other measurements.

It usually takes two people to safely deploy the CDT, even in calm seas.

discussing a CTD cast

Samantha Allen (left) and co-chief scientist Dr. Sandra Brooke (right) discuss a late afternoon CTD cast in Baltimore Canyon. Photo: S.W. Ross

Photo Credit: S.W. Ross

Samantha Allen (left, Nancy Foster crew) and Caitlin Casar (right, USGS) launch the CDT from the Nancy Foster over Baltimore Canyon. Photo: S.W. Ross

One Comment leave one →
  1. liz baird permalink
    June 9, 2011 10:37 am

    What a great piece of gear to use to get a good picture of the water chemistry. If you were going to add another sensor or probe to the CTD what would it be?

    Looks like the seas are smooth in the photos which I am certain is making the work of deploying and recovering the CTD easier.

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