Let's take a closer look at the equipment Part 1: CTD

Closer Look at Equipment
E., 4th grade, requests we take a closer look at the equipment we use on the ship.

Yesterday, we worked in test deployment of the CTD, before hitting rough weather, to ensure we're all ready when we get to Antarctica.

The CTD is an oceanography instrument used to determine conductivity, temperature and depth of ocean water samples (this is how it gets its name). The instrument is a cluster canisters—that collect samples at different depths—and sensors which measure conductivity (used to determine salinity), temperature and pressure and send data back to the ship in real time.

CTD on the NBP
The CTD used on the R/V Nathaniel B Palmer.

When the CTD is deployed, they open a door in the side of the ship and send this 6 foot plus structure out the side. Sometimes the seas can be a little rough and flood the deployment room. To be in the room as they deploy you have to be tethered to the boat.

CTD Deploy
Marine Technicians on the R/V Nathaniel B Palmer deploy the CTD.

As the CTD descends, it takes data about the water that it sends back to the boat. One of the scientists or technicians works at a station collecting and compiling data to create a profile of the water.

CTD Station
Electrical Technician, George Aukon, running the CTD from a station on the ship.

After the CTD is brought back on board the ship, water samples are collected to be tested for salinity, isotopes or other materials of interest later.

CTD Sample Collage
Left: Dr. David Porter collecting a water sample for the CTD on the R/V Nathaniel B. Palmer; Right: A water sample collected from the CTD on the R/V Nathaniel B Palmer to be run through later tests.

Once we've reached our destination, we'll be using the CTD to measure the temperature and salinity of ocean water at different depths near ice streams to determine if warm water is melting ice sheets and glaciers from below.

As for the storm, it hit last night and things were rough. I had trouble walking around and was almost tossed out of bed by the swell. Things are a little calmer this morning, but we're in for another round of rocky weather again later today.

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Jeff Peters

How far down does the CTD go?

Dominique Richardson

Great question! Dr. Raul Guerrero, one of our CTD scientists on board, whom we will meet in a journal entry soon, says: Our CTD can go to about
6,000m deep (that's almost 20,000 feet!). This is good enough to cover
about 98% of the ocean. However, some particularly deep areas like the
Mariana Trench, require special CTDs that can go to 10,000m or more. On
our expedition we will be looking at the continental shelf of Antarctica
where we will deploy the CTD to about 4,000m and under the sea ice where
we will deploy from 500 to 1,000m.

Genelle Curiel

Thanks Dominique. I was wondering what all those canisters were for.

Dominique Richardson

Hi Genelle,I'm so glad you're following us on the blog! Once we reach the Antarctic coast we'll be using the CTD to collect water samples at
depth. We're also planning to do take some very deep samples with the
CTD. So if they weather cooperates, I'll have some fun new photos to

Jillian Worssam

Great Journal Dominique, My students will be reading tomorrow. One quick question. Are there other instruments that the scientists will be using to collect and or sample water?
thanks Jillian Oh, and we want more pictures of you!

Dominique Richardson

Hi Jillian! I'm excited you and your students will be reading along! Hi to all of them. I hope they enter the "guess first sea ice" contest.

We have a lot more equipment on board that we'll be using to collect
data. While we'll only be using the CTD to collect samples, we can also
use an XBT to measure temperature, the multi-beam to map the sea floor,
kasten cores to to take mud samples and we'll even be using drones to
observe sea ice on this trip! We're still in transit so the CTD is the
only thing we've used so far. I promise there are lots more blogs on
other equipment, and pictures of us using it, to come!

And when we're done transiting there will be more pictures of me too.

Jacob Partida

When the sea is really rough, are there certain functions on the ship that must be put off, such as lab work?

Dominique Richardson

Hi Jacob, I'm excited you're following along! Hope all is well at school for you. This is a great question! When the sea is really rough
pretty much all the big lab work shuts down. We can't deploy sensitive
equipment like the CTD. And we can't hold still long enough to take
cores. And there is too much turbulence for the multi-beam to get good
data.... You get the idea. Basically it can get so rough the captain
shuts down the outer deck and we can't really do anything new. We can
run samples we've already collected and process data we already have (if
whoever is doing the processing isn't too sea sick to stare at a monitor
for hours), but that's about it. It's hard to explain how rough it is
out here right now, but all the outer decks are closed and things go
flying off tables unless they're strapped down, so we're not getting
much work done yet. It'll be much calmer once we're in the sea ice. I'll
try posting a few more pictures of the rough weather as soon as I can.