Amanda Dice: Ending Week 1 at Line 8, August 26, 2017

NOAA Teacher at Sea

Amanda Dice

Aboard Oscar Dyson

August 21 – September 2, 2017

 

Mission: Juvenile Pollock Fishery Survey

map cropped

Oscar Dyson moves across the Shelikof Straight to collect the Line 8 samples

Geographic area of cruise: Western Gulf of Alaska

Date: August 26, 2017

Weather Data: 13.2 C, cloudy with light rain

Latitude 57 36.6 N, Longitude 155 .008 N

 

 

Science and Technology Log

As part of this survey, the scientists onboard collect data from what is known as “Line 8”. This is a line of seven sampling stations, positioned only a few miles apart, near the southern opening of Shelikof Straight between Kodiak Island and the Alaskan Peninsula. Water samples are taken at different depths at each sampling station to measure several different properties of the water. This study is focused on profiling water temperature and salinity, and measuring the quantities of nutrients and phytoplankton in the water.

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The CTD rosette is lowered into the water using a winch – as seen from above.

To collect this data, a conductivity and temperature at depth (CTD) instrument is lowered into the water. This instrument can take water samples at different depths, by using its eleven canisters, or Niskin bottles. The water collected in the Niskin bottles will be used to determine the nutrient quantities at each station. The rosette of Niskin bottles also has sensors on it that measure phytoplankton quantities, depth, temperature, and how conductive the water is. Scientists can use the readings from conductivity and temperature meters to determine the salinity of the water.

Each Niskin bottle has a stopper at the top and the bottom. The CTD goes into the water with both ends of each Niskin bottle in the open position. The CTD is then lowered to a determined depth, depending on how deep the water is at each station. There is a depth meter on the CTD that relays its position to computers on board the ship. The survey team communicates its position to the deck crew who operate the winch to raise and lower it.

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Niskin bottles are lowered into the water with the stoppers at both ends open.

When the CTD is raised to the first sampling depth, the survey crew clicks a button on a monitor, which closes the stoppers on both ends of Niskin bottle #1, capturing a water sample inside. The CTD is then raised to the next sampling depth where Niskin bottle #2 is closed. This process continues until all the samples have been collected. A computer on board records the depth, conductivity and temperature of the water as the CTD changes position. A line appears across the graph of this data to show where each sample was taken. After the Niskin bottles on the CTD are filled, it is brought back onto the deck of the ship.

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They let me take control of closing the Niskin bottles at the sampling depths!

CTD screen cropped

I used this screen to read the data coming back from the CTD and to hit the bottle to close each Niskin bottle. The purple horizontal lines on the graph on the right indicate where each one was closed.

Water is collected through a valve near the bottom of each Niskin bottle. A sample of water from each depth is placed in a labeled jar. This study is interested in measuring the quantity of nutrients in the water samples. To do this it is important to have samples without phytoplankton in them. Special syringes with filters are used to screen out any phytoplankton in the samples.

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Syringes with special filters to screen out phytoplankton are used to collect water samples from the Niskin bottles.

The “Line 8” stations have been sampled for nutrient, plankton, and physical water properties for many years. The data from the samples we collected will be added to the larger data set maintained by the Ecosystems and Fisheries-Oceanography Coordinated Investigations (Eco-FOCI), Seattle, Washington. This NOAA Program has data on how the marine ecosystem in this area has changed over the last few decades. When data spans a long time frame, like this study does, scientists can identify trends that might be related to the seasons and to inter-annual variation in ocean conditions. The samples continue to be collected because proper nutrient levels are important to maintaining healthy phytoplankton populations, which are the basis of most marine food webs.

 

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Collecting water samples from a Niskin bottle.

Personal Log

As we travel from one station to the next, I have some time to talk with other members of the science team and the crew. I have really enjoyed learning about places all over the world by listening to people’s stories. Most people aboard this ship travel many times a year for their work or have lived in remote places to conduct their scientific studies. Their stories inspire me to keep exploring the planet and to always search for new things to learn!

Did you know?

Niskin bottles must be lowered into the water with both ends open to avoid getting an air bubble trapped inside of them. Pressure increases as depth under water increases. Niskin bottles are often lowered down below 150 meters, where the pressure can be intense. If an air bubble were to get trapped inside, the pressure at these depths would cause air bubble to expand so much that it might damage the Niskin bottle!

DJ Kast, Pre-Cruise, May 18, 2015

NOAA Teacher at Sea
Dieuwertje “DJ” Kast
Aboard NOAA Ship Henry B. Bigelow
May 19 – June 3, 2015

Mission: Ecosystem Monitoring Survey
Geographical area of cruise: East Coast

Date: May 18, 2015 (Pre-cruise)

Personal Log

Chris Melrose picked me up from the hotel and really helped me get a grasp of life aboard a research vessel. I learned all about Narragansett Bay and the lab here in Rhode Island.

I then met Jerry Prezioso, the Chief Scientist for the voyage, who gave me a great tour of the Narragansett Bay Lab. I learned what an XBT (expendable bathythermograph) was and how it measures temperature at various depths.

XBT  Photo by: DJ Kast

XBT
Photo by: DJ Kast

 

I learned how a Niskin bottle works and how many Niskin bottles lined up in a circle to make a piece of equipment called a rosette. The Niskin bottle is like a hollow tube with a mechanism that closes the tube at a specific depth that will then bring a water sample indicative of that depth. They apparently cost $400 each.  I am already making plans on how to make a DYI one for the classroom.

Niskin Bottle Photo by: DJ Kast

Niskin Bottle
Photo by: DJ Kast

This is a Rosette with 12 niskin bottles. Photo by: DJ Kast

This is a Rosette with 12 niskin bottles. Photo by: DJ Kast

With Jerry, I also met Ruth Briggs who works for the Narragansett Bay Apex Predators division and she showed me the shark tags that she has citizen scientists put onto sharks on the base of their dorsal (top) fin that they catch. When the sharks are caught again, the information she requests is sent back to her and includes species, size, sex, location to shore, and weight. She even let me borrow a decommissioned tag to show to my students in California.

Decommissioned shark tag from the Narragansett Bay Apex Predators Division Photo by: DJ Kast

Decommissioned shark tag from the Narragansett Bay Apex Predators Division
Photo by: DJ Kast

 

I saw a drifter buoy that I will be decorating with all of my programs (USC, JEP, YSP and NAI) logos.

Jerry also sent me the map of all the stations that we will be visiting on our ship and at each station we are projected to measure salinity, depth, temperature, nutrients and plankton! I am so excited! We are expected to go as far south as North Carolina and as far north as the Bay of Fundy in Canada (International Waters!!!).

TAS and the NOAA Ship Arrival

My stateroom is amazing! My roommate and I even have our own head (bathroom) in our room with sink, shower and all. There are two beds in a bunk bed format, and since I showed up about 6 hours before the other scientists I chose the bottom bunk and the cabinet I wanted for my stuff. I unpacked (and gladly didn’t over pack) and managed to fit it all in the closet that was given to us. I feel so fortunate to have such amazing accommodations like this.

Important People who Keep the Ship Afloat and on Course

Today I met the Operations Officer, Laura, who showed me the ropes and introduced me to people on the ship at dinner at the bowling alley on the naval base here in Newport, RI. She also showed me the buoy yard filled with lots of different buoys that indicate different paths of travel and safe/unsafe waters for ships coming into port.

I entered a yard of buoys on the Newport Naval Base and here I am for a size comparison. They are HUGE!

I entered a yard of buoys on the Newport Naval Base and here I am for a size comparison. They are HUGE!

Here is a look at what happens when  a buoy is freshly painted and when its being fouled by marine organisms and algae (RUST!) Photo by: DJ Kast

Here is a look at what happens when a buoy is freshly painted and when its being fouled by marine organisms and algae (RUST!) Photo by: DJ Kast

 

Important Ship Personnel
CO: Commanding Officer
XO: Executive Officer
CME: Chief Marine Officer
OO or Ops: Operations Officer= Laura
NO: Navigational Officer or Nav= Eric
CB: Chief Boson or Deck Boss= Adrian
AB: Able Seaman or a Deckhand = Roger

Meal Schedule
I also learned about food times (Very important).
7AM- 8 AM or 0700-0800 hours= Breakfast
11- 12 PM or 1100-1200 hours= Lunch
5- 6 PM or 1700-1800 hours = Dinner

Roommate in Stateroom 2-22

 

DJ Kast on the Gateway Photo by: DJ Kast

DJ Kast on the Gangway
Photo by: DJ Kast

Here I am boarding the NOAA Henry B. Bigelow Photo by: DJ Kast

Here I am boarding the NOAA Henry B. Bigelow
Photo by: DJ Kast

 

I met my amazing roommate Megan and she is a master’s student at the University of Maine. We will sadly have opposite schedules for most of the trip because I will be on the 12 PM- 12 AM shift and she will be on the 12 AM- 12 PM shift. We have a lot of things in common including our love of the ocean, geology and Harry Potter. She will be looking at dissolved nutrients in the water and she will be monitoring the instruments that measure conductivity, temperature and depth or (CTD) and requesting water samples while at various stations.

Kate DeLussey: TowCam Anyone? July 11, 2012

NOAA Teacher at Sea
Kate DeLussey
Onboard NOAA Ship Henry B. Bigelow
July 3 – 18, 2012

Mission:  Deep-Sea Corals and Benthic Habitat:  Ground truthing and exploration in deepwater canyons off the Northeast
Geographical area of cruise: Atlantic Ocean, Leaving from Newport, RI
Date:  Wednesday, July 11, 2012

Everyone works at sea. Here I am helping with the pre-deployment checklist.   (See how wet Lowell is!  He has been to the ocean floor many times.)

Location:
Latitude:  39.8493°
Longitude: -69.5506 °

Weather Data from the Bridge:
Air Temperature: 19.30° C
Wind Speed: 20.74 knots  5  on the Beaufort  wind scale
Relative Humidity:  88.00%
Barometric Pressure: 1,020.80 mb
Surface Water Temperature: 21.39° C

Science and Technology Log

High winds, moderately rough seas, and difficulties with the ship’s positioning system all contributed to the delay of the first scheduled launch of TowCam on our midnight shift.  Even though the necessary decision meant a loss of precious underwater time, it is better to delay than risk losing  expensive equipment.

When the seas calmed down we were able to launch TowCam, but first we had to go through the pre-launch checklist.  I helped Lizet as she prepared TowCam.

Did you guess that Batteries power the components of TowCam?          Lizet must test the batteries  before and after each launch.

The batteries are under very high pressure when TowCam goes to the ocean floor so we have to push out the air before each trip.   I help by tightening the battery caps.  Every time I am on deck I must put safety first.  I always wear a hard hat and the life vest.

One of my jobs is to help with TowCam.

When everything has been checked and double checked, the operator gives the signal, and the deck crew of the Bigelow use the winch and tag lines to launch TowCam on its next mission.

The winch swings TowCam off the deck and lowers it into the ocean.

Look at the picture carefully.  The deck crew always wear their safety equipment too!  They hook themselves to the ship by their belts, and they wear safety vests and hardhats.  The deck crew on Bigelow also make sure everyone follows the safety rules.

As soon at TowCam is in the water, everyone wants to view the images sent by the camera, but the TowCam operator must keep an eye on the monitors.

These are six of the monitors used to control and guide TowCam.

TowCam operators watch eight different computer monitors to control TowCam’s movements.  With the help of mathematic modelers and previously collected data about the structure of the ocean floor, the scientists choose  locations where they think they will find corals. These locations are called “stations.”

This map from the NOAA web site shows the track of the Bigelow. The places where the lines cross over one another are some of the stations where the scientists looked for coral

The ship must make very small movements to get the camera in the correct place on station. The operator will say something like, “Lab to Bridge- move 10 m to the North please.”… Then they watch the camera and the monitors to see if TowCam moves to the correct position.   Sometimes TowCam floats right past the spot scientists want to see, and then the operators have to try to get it back into position to take the pictures.  Not every station has the corals the scientists hope to find.  But even knowing where corals are not is important information.  After several hours of picture taking, we move on the next station.

I sit next to the TowCam operator and keep the logs.

Even in calm seas controlling TowCam is a challenging process.  Remember, TowCam hovers over the ocean floor  attached to the ship by a wire.   Fully loaded it weighs over 800 pounds in the air.  Since the ship moves TowCam by pulling it, it is not easy to follow the scientists’ plan.

However, when the perfect coral images appear on the screen, no one thinks about how hard they were to find.  We all crowd around the monitors and watch in amazement.  The scientists try to figure out  types of corals in the picture, and then they wait for the next picture to see if there are even more!  We have found corals at lots of stations!

Think about a time you tried to pull something tied to the back of  a rope.  Was it easy to steer?  Did it get stuck?  

Personal Log

We have talked a bit about how scientists find and try to study corals using the underwater camera and other sensors on TowCam.  On other missions scientists  sometimes use remote control underwater vehicles ROVs.   Unlike TowCam which is dragged behind the ship, these vehicles are more versatile because they are driven and controlled remotely using a joy stick similar to the ones you use for computer games.    Sometimes scientists even go to the ocean floor and drive themselves around using submersibles.  One thing is certain,  you have to get under the water to study corals.

Scientists go to all this trouble because corals are important to our Earth’s oceans. They are very old, and they provide habitat for other animals. 

As you grow, it will be your job to find ways to study and protect corals and all other living things in the oceans. 

Who knows how corals could help us in the future!

Polyps are extended from deep-sea coral colony.
Photo from NOAA Undersea Research Program.

Kate DeLussey: Lowell Searches Beneath the Ocean, July 8, 2012

NOAA Teacher at Sea
Kate DeLussey
Onboard NOAA Ship Henry B. Bigelow
July 3 – 18, 2012

Mission:  Deep-Sea Corals and Benthic Habitat:  Ground truthing and exploration in deepwater canyons off the Northeast
Geographical area of cruise: Atlantic Ocean, Leaving from Newport, RI
Date:  Sunday, July 8, 2012


Location:
Latitude:  38.9580 °
Longitude: -72.4577 °

Liz thought we needed our school mascot on the mission. When she went to the store, she brought back Lowell the Lion.

Weather Data from the Bridge:
Air Temperature: 24.60° C
Wind Speed: 4.5 knots
Relative Humidity:  88.00%
Barometric Pressure: 1,010.30 mb
Surface Water Temperature: 24.49° C

 

Science and Technology Log

Look who went to the bottom of the ocean on TowCam.  No you silly students…not me!  TowCam is exploring the deep ocean between the twilight zone and the midnight zone, and it is not possible for people to travel in deep water without very special equipment.

Our mascot Lowell Lion accompanied TowCam as it was deployed for Tow 2.

At this location, TowCam reached a depth of over 1900 meters below the surface of the ocean.  That is more than one mile-straight down!  It was a good mission.  The camera was sending some very interesting images back to the ship.  As I was doing my job logging, I was watching these first images.  I was able to see hard bottom- the best habitat for corals.  I also saw fish and sea stars, and then I saw the corals! They looked like little fuzzies on the rocks. The scientists had the ship hold position right over of the corals so they could take lots of pictures.  The TowCam operator used controls on the ship to raise and lower TowCam to get close to the corals without touching the cliffs where the corals were living.

Students:   Can you imagine using remote controls to move the TowCam?  I bet you would be good at it.  Perhaps the video games you play will help prepare you to fly TowCam when you finish college. 

Doesn’t Lowell look proud?  He survived his first dive and brought some interesting friends back with him.

Well, when TowCam came back on the ship, Lowell was very wet, but he handled the cold, dark high pressure very well.   Thanks to Greg and Lizet, Lowell stayed on the TowCam Sled!

Once TowCam was secured on the deck. We went out to take care of TowCam.   What a big surprise to find other creatures hitchhiking on TowCam.   Lowell the Lion must have made some friends.

This sea star was hidden on TowCam

The first deep sea visitor was a spiny orange sea star.

The orange sea star was found on TowCam deployment #2.

Isn’t it beautiful?  We all rushed to see it.  Dr. Nizinski carefully examined and measured the sea star.   She used her tweezers to pick up a tiny sample the sea star leg, and she put the sample into a little bottle with a label.  She will use the sample to test the DNA to help classify the sea star.  She will find the sea star’s “family.”

It was exciting to find the sea star, but when we looked further one of the scientists saw a piece of coral tucked in a hiding place on TowCam.   Dr. Martha took care of the coral also.  The coral will become a permanent record that reminds us that this type of coral lives here.

   These corals were hidden in the batteries after Tow 2. July 8, 2012

 

Do you see how carefully the sample is documented?  Some of the things we do in school like labeling and dating our illustrations and our work prepare you to be a scientist.  

Many years from now someone can look at the coral in this picture and see that the sample was collected on the Bigelow TowCam #2, on July 8th.  The ruler in the picture helps everyone know the approximate size.

One of the components on TowCam we have not talked about yet is the slurp.  

 

TowCam slurp

Try to find the Slurp on TowCam.              

The “slurp” is really an underwater vacuum cleaner that sucks up water, sediment, and sometimes small creatures.  When TowCam is in deep water, the scientists watch the images to decide when it is a good time to trigger the slurp.   They have to choose carefully because the slurp can be done only once on each trip to the bottom.

The scientists used the slurp on Tow #2.  The collection container looked like it just had “mud” and water.   It was emptied through a sieve to separate the “mud” and other things from water.  The scientists carefully examined what looked like regular mud but tiny organisms like bivalves, gastropods, and small brittle stars were found in the sieve.  These animals were also handled very carefully.

This brittle star was found with mud and sediment slurped from the ocean bottom.

This brittle star was found with mud and sediment that was slurped from the ocean bottom.

Can you find any other living things in this picture?

 

You never know what is hiding in the mud.  I bet we could do this kind of exploring right in our school’s courtyard.  What do you think we could find if we examined our mud?

 

Kate DeLussey on the Bigelow July 12


Personal Log

I think we should talk about the ocean today.  Many of us have had some experience with the ocean.  Maybe you have been to the beach, and maybe you have even seen some of the cool creatures that can be found on the beach.  I have seen crabs, horseshoe crabs, clams, and plenty of jellyfish, but the scientists on Bigelow are working in a very different part of the ocean.

If you visit the beach, you are only swimming in a teeny tiny part of the ocean.  Maybe you are allowed in the ocean up to your knees to a depth of 20 inches (about 1/2 a meter), or maybe you are brave and are able to go in the ocean with an adult up to your waist to a depth of 30 inches (about 3/4 a meter).  Even if you have been crabbing or fishing in the Delaware Bay where the average depth is 50 feet (15.24 meters) you have been in only the most shallow part of the ocean.  TowCam has been down as far as 1.2 miles (2000 meters).  That is not even the deepest ocean!  The ocean is divided into zones according to depth and sunlight penetration.  I learned about the top three zones.

  • The sunlight zone– the upper 200 meters of the ocean are also called the euphotic zone.  Many fish, marine mammals like dolphins and whales, and sea turtles live in this band of the ocean.  At these depths there is light, plants, and food for creatures to survive.  Not much light penetrates past this zone.
  • The twilight zone– this middle zone is between 200 meters and 1000 meters and is called the disphotic zone.  Because of the lack of light, plants cannot live in this zone.  Many animals like bioluminescent creatures with twinkling lights do live in this zone.  Some examples of other creatures living in this zone includes: crabs, gastropods, octopus, urchins, and sand dollars.
  • The midnight zone– this zone is below 1000 meters and is also called the aphoticzone has no sunlight and is absolutely dark.  At these depths the water pressure is extreme, and the temperature is near freezing.  90% of the ocean is in the midnight zone.So you can see that when you are at the beach, you are never in the “Deep Ocean.”  You are still in a great place to find many amazing creatures.  Keep your eyes open!  Be curious! Make sure you do some exploring the next time you visit this important habitat.  Then write and tell me about the things you find. Try to draw and label the three zones of the ocean.  Be sure to draw the living things in the correct zone.
  • Next time:  Someone will be working on deck getting TowCam ready for deployment.  Hint:   It will not be Lowell. : )

Kate DeLussey: Underway and Under the Sea, July 7, 2012

NOAA Teacher at Sea
Kate DeLussey
Onboard NOAA Ship Henry B. Bigelow
July 3 – 18, 2012

Mission:  Deep-Sea Corals and Benthic Habitat:  Ground truthing and exploration in deepwater canyons off the Northeast
Geographical area of cruise: Atlantic Ocean, Leaving from  Newport, RI
Date:  Monday, July 7 , 2012

Location:

Here I am on the bridge of Henry B. Bigelow.  ENS. Zygas put me to work looking up changes for navigational charts.

Latitude:  39.29 °
Longitude: -72.25°

Weather Data from the Bridge:

Air Temperature: 23.40° C
Wind Speed: 15 Kts
Relative Humidity:  90.00%
Barometric Pressure: 1,011.99 mb
Surface Water Temperature: 23.66° C

Science and Technology Log

At 7:00 pm last night the Henry B. Bigelow left Pier 2 from the Newport Naval Base.  Narragansett Bay was crowded with sailboats, yachts, and even a tall ship, but once we passed under the bridge, we knew we were really on our way.  Now that we are at sea, everyone onboard will begin his or her watch.  I will be working 12 am to 12 pm along with some of the scientists.  Even though I never worked night work before, I was excited to learn about my jobs!

One of our jobs is to keep track of the “TowCam” when it is in the water.  Every ten minutes while the TowCam is deployed (sent underwater) we log the location of the ship using Latitude and Longitude. We also have to keep track of other important data like depth.  The information is logged on the computer in a spreadsheet and then the points are plotted on a map.  A single deployment can last 8 hours.  That is a lot of data logging!  These documents provide back up in case something were to happen to the data that is stored electronically.   I will have other jobs also, and to get ready for those duties, Lizet helped me get to know the TowCam better by explaining each component.

Students:  See if you can find each part Lizet showed me on the picture of the TowCam in my last blog.

 

The camera on TowCam faces down to capture images in the deep ocean

Camera– The camera is the most important part of the TowCam.  You need a very special camera that will work in cold deep water.  When the TowCam is close to the ocean floor this digital camera takes one picture every 10 seconds. The thumbnails or samples of the pictures are sent to computers on the ship by the data link. The camera operator described the thumbnails like the picture you see when you look at the back of your camera. When I look at the thumbnails I don’t usually see much in the picture.  The scientists know what they are looking for, and they can recognize hard bottom on the ocean floor and corals.  They see fish and other sea creatures too, and when they see a picture they like, they will ask the ship navigator to “hold the setting” so they can take more pictures.  Remember, the scientists are trying to find corals, or places where corals might live.  If they have a picture, they have proof that these special animals live in a certain habitat that should be protected.

Strobe light– There are two strobe lights on the TowCam.  The deep ocean does not have

Strobe light illuminates the darkness of the deep ocean

natural lighting because the sunlight does not reach down that far.  The strobe light flashes each time a picture is taken.  If the TowCam did not have these special lights, you would not be able to see any of the pictures from the camera.  These lights are tested every time the TowCam is deployed.

The CTD measures Conductivity, Temperature, and Depth

      CTD- The CTD is an instrument that has sensors to measure Conductivity, Temperature, and Depth in a certain water column.  It is attached to the TowCam and the information from the CTD is sent to the computers through the datalink.  This information gives the scientists a better understanding about the ocean water and the habitat for the creatures they are looking for.  Look for more components on the TowCam.  How do you think the TowCam gets its power?

 

Personal Log

I am getting adjusted to life at sea.  For the first few days, when we were still on the dock I did not have much to do.  ESN Zygas gave me a job and let me find updates for the navigational charts that are stored on the bridge.  The charts are maps of the oceans and waterways that help the NOAA Corps team steer the boat, and these charts get updated when markers like buoys are moved or when the water depths and locations change.  Up-to-date charts keep the ships safe.  I was glad to do a job that helped keep us safe.  Now that we are at sea, I have been working my watch.  The work varies.  We have hours of watching TowCam on the bottom of the sea and charting the positions of the ship. Then we have the excitement when the camera comes on-board with pictures and samples that need to be processed.

One of the best things about this experience is that I am the student just like my students at Lowell.  I am excited to learn all of the new things, but I am frustrated when I don’t understand.  Sometimes I am embarrassed when I have to ask questions.  Yesterday I was working with some of the images and I was looking for fish. All I had to do was write “yes” there is a fish in this photo.  Well, I had to ask Dave (one of the scientists) for help.  I had to ask, “Is this a fish?”  Can you imagine that?  A teacher like me not knowing a fish!  It was like finding the hidden pictures in the Highlight magazine!

So instead of being frustrated, I am open to learning new things.  I keep practicing and try not to make mistakes, but when I do make those mistakes, I just try again. By the time we go through the thousands of pictures I may not be a pro, but I will be better.  I can see that I am improving already.  I can find the red fish without zooming in -the red color probably helps!

Next time:  Wait until you see who went to the bottom of the ocean on TowCam.  You won’t believe what they brought back with them.

Until next time:)

Wes Struble: Analysis of Water Samples, March 4, 2012

NOAA Teacher at Sea
Wes Struble
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: March 4, 2012

Weather Data from the Bridge

Position:30 deg 37 min North Latitude & 79 deg 29 min West Longitude
Windspeed: 30 knots
Wind Direction: North
Air Temperature: 14.1 deg C / 57.4 deg F
Water Temperature: 25.6 deg C / 78.4 deg F
Atm Pressure: 1007.2 mb
Water Depth:740 meters / 2428 feet
Cloud Cover: 85%
Cloud Type: Cumulonimbus and Stratus

Science/Technology Log:

In the previous log I described a CTD cast in detail from start to finish. Now that the CTD platform is on the deck of the Ron Brown the actual sampling process can begin. The CTD has a number of Niskin bottles holding a little more than 10 liters of water each. Water samples from each bottle must be collected and analyzed for various parameters which could include: Salinity, Oxygen content, Inorganic carbon, and others. On this cruise most of the CTD casts were sampled for both salinity and dissolved oxygen.

The first step in measuring salinity involves a careful rinsing of the sample bottles. After a standard three rinses, the bottle is filled and the depth from which the water was sampled is recorded for each bottle.

As a beautiful western Atlantic sunset falls on the Ron Brown another night of CTD's begins

I prepare a water sample for dissolved oxygen analysis after a CTD Cast at 2:00 am

The dissolved oxygen analysis lab station in one of the science labs on the Ron Brown

The full sample bottles are then either taken to the dissolved oxygen lab station or the Salinity lab station for analysis.

A close-up of the amperometric titration apparatus for analysis of dissolved oxygen in one of the science labs on the Ron Brown. A solution of Manganese Chloride and a combination of Sodium Hydroxide/Sodium Iodide is added to the water sample to sequester the oxygen and then when the temperature is stable the solution is amperometrically titrated with thiosulfate.

The Ron Brown off the starboard stern from the workboat

The "climate airlock" leading to the salinity analysis lab. The airlock helps keep the water samples under constant temperature and humidity conditions.

The two Autosals in the Salinity lab. These are precision instruments for measuring the salinity of seawater

A east-west cross-section across the eastern Atlantic Ocean. The eastern US coast is at left. The diagram illustrates north (reds)-south (blues) movement of the Antilles and Deep Western Boundary Current. Vertical scale in meters horizontal scale in 100,000 meter units (100 kilometers)

Wes Struble: What in the World Is a CTD Cast? March 2, 2012

NOAA Teacher at Sea
Wes Struble
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: March 2, 2012

Weather Data from the Bridge

Position: 26 degrees 19 minutes North Latitude & 79 degrees 55 minutes West Longitude (8 miles west of Florida’s coast)
Windspeed: 14 knots
Wind Direction: South
Air Temperature: 25.4 deg C / 77.7 deg F
Water Temperature: 26.1 deg C / 79 deg F
Atm Pressure: 1014.7 mb
Water Depth: 242 m / 794 feet
Cloud Cover: none
Cloud Type: NA

Science/Technology Log:

There are four different ship’s stations that are involved in a CTD (Conductivity, Temperature, & Depth) operation: the bridge, the survey team, the winch operator, and the computer room. The bridge is responsible to keep the ship on position and stable over a predetermined latitude and longitude. The survey team is responsible for preparing the CTD platform for deployment and securing it back on deck at the completion of the cast. The winch operator controls the actual motion of the CTD platform by the use of a hoist.  The computer lab relays commands to the winch and survey team in reference to testing and sampling depths, and when to start and stop the ascent and descent of the platform. The CTD platform can carry many types of instruments depending upon the nature of the research being conducted. During this cruise our platform usually contained two each of a temperature gauge, conductivity gauge (from which you can obtain salinity), and oxygen gauge.  In addition there is one pressure gauge and a transmissometer (that measures the turbity of water which is an indicator of the phytoplankton), 23 Niskin water sampling bottles, and two Acoustic Doppler Range finders – one pointing toward the surface and one pointing at the sea floor.

The CTD (Conductivity, Temperature, & Depth) platform on the Ron Brown. The long grey cylinders are the water sampling Niskin bottles, the yellow and blue device at the bottom in the Acoustic Doppler Current Profiler (for measuring distance to the sea floor) for measuring the distance to the sea floor during descent phase of a cast, the grey cylinders are weights, and the green cylinder is the power supply.

A Niskin Bottle with my Nike shoe for scale

The CTD platform being lowered over the side for start of another cast.

The "downlooking" ADCP (Acoustic Doppler Current Profiler mounted on the CTD.

The "up-looking" ADCP (Acoustic Doppler Current Profiler) mounted on the CTD

The Niskin Bottle trigger release. This device is used to remotely close the Niskin bottles at depth

The bridge of the Ron Brown during a CTD cast

     A CTD cast begins when the ship arrives at prearranged coordinates of latitude and longitude. The bridge will announce that we are “on station”.

A photo of the Ron Brown off the coast of Grand Bahama Island

   The survey team acknowledges and then raises the CTD platform and places it is the water at the surface for a minute or two. Then after receiving a signal from the computer operator that all functions are operating within normal parameters the platform is lowered to 10 meters and held there for two minutes to allow the instruments to stabilize.

Here I am starting my midnight to 6 :00 am shift at the CTD computer control station in the computer lab of the NOAA Ship Ronald H Brown

The "brains" of the CTD. This device also contains the pressure sensor.

   After the two minute hold at 10 meters the entire platform is brought back to the surface and the log is started as the package is lowered. The descent begins at about 30 meters/minute and eventually reaches 60 meters/minute. Many of the deep water casts on this cruise were between 4000 m and 5500 meters (about 13000 ft and 18,000 ft) and take over an hour to reach the bottom. While the descent takes place all the instruments are recording data which is stored and plotted in real time at the computer monitor.   When the CTD platform is 10 meters from the bottom the descent is stopped and the first water sample is collected by sending a signal that closes the first Niskin bottle. At this point the CTD slowly begins its climb back to the surface (another hour or more) stopping at designated depths to collect water samples.After the last Niskin bottle is closed at the surface, the CTD platform is brought back on deck, the water samples are removed, and the entire platform is prepared for the next cast.

Here I am on the weather deck in my favorite chair on the ship. I enjoy relaxing here in the sun in the morning after a night shift at the CTD computer station.

Another beautiful western Atlantic pre-sunset. I enjoyed many of these during the cruise.

The early sun rising in the east off the stern of the Ron Brown brings another night of CTD's to an end.