Sound – NOAA Teacher at Sea Blog

September 13, 2024November 9, 2024

Lisa Werner: How Does Communication with Popoki Work? September 11, 2024

NOAA Teacher at Sea

Lisa Werner

Aboard NOAA Ship Bell M. Shimada

August 29-September 13, 2024

Mission: EXPRESS Project

Geographic Area of Cruise: Pacific Coast, near Northern California

Date: September 11, 2024

Weather Data from the Bridge (Coquille Bank):

Latitude: 42º58.378’ N

Longitude: 124º50.146’W

Wind Speed: 23.78 knots

Air Temperature: 14.3ºC/57.74ºF

Conditions: Rain

Science Log

Let’s talk about how Popoki, the autonomous underwater vehicle (or AUV), ‘converses’ with the AUV pilot aboard the ship. The map and directions for the route Popoki will be mapping is programmed into her computers ahead of each dive. On this mission, Popoki has been deployed daily, so every evening, the scientists carefully plan out where she will go on each deployment. They also plan the path Popoki will go when on location – this cruise she has made a lot of sawtooth-shaped patterns to give the scientists the greatest survey of what is in the areas they want to study.

photo of a computer screen showing, at center, an image from a computer-generated model of the underwater bathymetry of an area. Overlaid on the image are topographic lines and depth numbers. overlaid on that is a zig-zagging white line showing Popoki's route. — *Of course, tomorrow’s dive pattern is not a sawtooth pattern. The pattern is drawn out in the white lines over the diagram of the ocean floor contour.*

Though this seems like it would be easy to set up Popoki and let her run her course, that is not quite the end of the story. During a dive, the ocean current is sometimes unknown in any given area, so the AUV pilot needs to be able to help Popoki adjust her positioning. It would not be a very big help to get pictures of an entirely different area than the scientists were aiming for because the ocean currents took Popoki to a different area of the sea floor. The scientists also need to be able to help Popoki if she gets stuck on fishing line, or if the conditions above the water change – such as weather changes or vessel traffic – that would require Popoki to surface ahead of her scheduled time.

To communicate with Popoki, an acoustic modem system is used. There is a modem aboard the ship that can send messages to Popoki through a series of chirping sounds. The pitches and lengths of the chirps are all part of the code that Popoki can understand. She has a device that ‘listens’ for these sounds and can then follow the coded instructions to alter her pre-programmed course. She also communicates regularly with the AUV pilot – sending the coordinates she believes she’s at, her depth, battery life, and how many pictures she has taken so far in the dive.

close-up view of a piece of electronic equipment inside a water-proof housing (with the lid removed to show the contents). There are knobs, dials, CAT-5 cables. — *The modem that communicates with Popoki*

Popoki’s communication device points upward, so when deployment is taking place, the scientists place a transducer into the water to use to communicate. Once Popoki is on her way to her programmed starting point, and farther away from the ship, the transducer is removed from the water.

crewmembers, wearing hard hats and life vests, lean over the rail of the ship and use hooked poles to guide a small yellow object suspended from what looks like a fishing pole safely down toward the water's surface. — *This is the transducer that is placed in the water for deployment*

Sometimes there are difficulties with this communication, and this is where the ship’ crew plays a very important role. The officers on the bridge work to position the ship in areas that allow for Popoki and the acoustic modem to speak to each other easily. The angle of the ship will change as Popoki goes through her programmed patterns, adjusting so that the chirps of the modem have a direct line to Popoki. Distance also plays an important part of the communication process – if the ship and Popoki are too far away from each other, there can be interference with the communication. Ocean current, wave heights and lengths, and other sounds coming from the ship can interfere with the communication, as well. The AUV pilot and the ship’s crew work very closely together throughout the entirety of the dive to help the Popoki and the pilot have clear communication.

photo over someone's shoulder of a computer screen displaying a gridded graph. on the graph is a simplified outline of the ship (like a rectangle with a triangle attached to one end) and some dots to the ship's port side — *AUV pilot Jeff Anderson’s screen showing the ship’s position and Popoki’s position (Denoted as dots)*

At this point, you may be wondering WHY do we use Popoki. I’m sure that you can see her benefits in exploring areas we have not yet seen, but the why actually goes much deeper than that (no pun intended). One of the first things Popoki is doing is looking at areas that are being considered for future offshore wind farm sites. There is a great interest in putting wind turbines over the ocean to create renewable energy for our country. Having been on the Pacific Ocean for 2 weeks now, I can definitely attest to the fact that the wind is very strong in these areas, so there is plenty of energy to harvest. Popoki is identifying the deep sea habitats and geological features on the seafloor that would need to be considered when anchoring any wind turbines.

Popoki is also looking at the changes to the habitats as a result of different regulations that have taken place in fishing areas in this region. Some of the locations we have visited were mapped out by Popoki in the past, and scientists are looking to see whether fishing regulations have helped the populations of ocean life return. Finally, Popoki has been looking for evidence of seeps in the ocean floor. These geological areas are spots where cracks in the ocean floor have occurred due to plate tectonics.

underwater image of the seafloor. it's mostly muddy, with only a little relief, but through the center is a dark crack in the floor, with what appears to be steam (maybe hotter water) rising out of it. we can also make out what might be corals, and a fish. — *Picture of an ocean seep (Photo credit: Popoki)*

Personal Log

The ship’s crew spends a lot of time preparing for safety. Just like we have fire, tornado, and lockdown drills in our school, the ship has drills to practice for emergencies as well. They need to be ready for any emergency, and everyone has a role to play. We have practiced the drills each week.

Throughout my time on NOAA Ship Bell M. Shimada, I have gotten to experience some pretty amazing things. However, my absolute favorite moment was getting “Helm time.” That’s right – I got to drive the ship! With Ops Officer Lieutenant Jaime Hendrix and Ensign Megan Sixt guiding me, I got to turn the ship to hard rudder, causing her to drive in a circle. I also got to get her back to her appropriate heading for the transit we were making, and then practice keeping her on course. It was really interesting to see how the ship reacts to the controls and to see what she does! I am so grateful to CO Laura Gibson for this opportunity, and really appreciate the help LT Hendrix and ENS Sixt gave me!

photo of Lisa wearing a bright red survival suit - all we can see of her is her eyes (with glasses) and a portion of her Teacher at Sea beanie hat. she stands on deck on a clear day and stretches her arms out for the photo — *Me wearing the Immersion (or “Gumby”) suit (Photo credit: Curt Whitmire)*

We practice where to gather, or ‘muster,’ in the event of a fire or abandoning ship. At the very beginning of the cruise, we get right to work with a tour of where to find the lifeboats, how to deploy them, and then we get to the drills.

Recently, I had the opportunity to learn to use the flares and the line thrower. The line thrower is used for ship to ship transfers or for rescuing someone who’s fallen overboard. Although it is really fun to get the experience to use these devices, it is definitely something that you hope only gets used in training. However, knowing they are there and that everyone knows how to use them makes you feel a bit better if an emergency does happen.

Lisa, wearing very large, thick gloves, poses near the ship's railing and smiles at the camera. in her left hand, over the railing, she holds a lit flare. it's a mostly clear day, and the sky is blue with a few clouds, and the ocean has a few whitecaps. — *I now know how to use the flares! (Photo credit: Alice Kojima-Clarke*)

Trying out the line thrower

We are not on autopilot!!! ENS Sixt and LT Hendrix helping me learn to drive a ship! (Photo credit: Randy Scott)

Music Connections

Communicating with Popoki has a lot to do with acoustics. Listening to her pilot talk about how important the angles between Popoki and the ship are reminded me a lot of preparing for a recital when I was a music education student at UW-Whitewater. As an undergraduate, we had several performance requirements per semester. For solo performances, the more experienced music majors would always pass on a very important piece of acoustic information to the new undergrads – always aim the trombone bell at the 3rd exit sign along the stage right wall. Hitting this sweet spot would cause the recital hall to ring, the trombone sound to be dark and full, and the experience to be the best for all who were listening. New trombone majors learned very quickly that this was not a piece of urban legend, but by bouncing the brass sound off of the wall at this angle, it was much more pleasant for the audience than to play directly at their faces.

view of an empty performance hall — *The beautiful Light Recital Hall at the University of Wisconsin-Whitewater – a great place to perform and explore acoustics! (Photo credit: Dr. Glenn Hayes*)

Communicating with Popoki is similar in a way – rather than bouncing her communications off of corners and walls, however, she responds better to the sound waves coming directly at her. She has a sweet spot, too, but it is more about decreasing the angles. This is a much more efficient method of communication for her, because she does not care about the timbre of her chirps!

Another great moment I really enjoyed during our time together was helping our Chief Scientist Dr. Clarke learn ukulele! I always believe that music is everywhere, and Dr. Clarke proved that theory again for me by bringing her ukulele along on this cruise when she heard the Teacher at Sea was a music teacher! Hopefully she had as much fun as I did!

In the computer lab, Lisa and Dr. Clarke sit in chairs facing one another. Lisa, smiling, leans forward to hold up an open laptop where Dr. Clarke can see it easily. Dr. Clarke watches the screen as she picks at her ukulele. — *Dr. Elizabeth Clarke showing off her virtuoso skills with a little “Hot Cross Buns” (Photo credit: Alice Kojima-Clarke*)

Sounds from the ship today will feature the sound of the ship’s engine outside from the very top deck of the ship.

This is the sound of the engine humming from the Fly Deck. You can also hear the waves, as we are in transit to our next station!

Student Questions

St. Bruno students are fascinated by sea creatures, and they have sent me on a quest to learn about the octopus. I think they will be very excited to see this picture and learn about the deep sea octopus!

underwater image of the seafood showing many brittle stars and some corals. in the lower right, there is a sponge, which since it is viewed from above appears as a white ring. inside the sponge, an octopus is curled up - we can see one eye and several tentacles — *Look at the octopus curled up in a sponge in the bottom right corner. You can see the octopus’s eye sticking out! (Photo credit: Popoki*)

Final Notes

The NOAA Teacher at Sea Program is an incredible opportunity for any teacher. As you can see, you do not need to be a science teacher in order to apply. There are so many connections to be made with the ocean, and students get really excited about learning through their teacher’s experience. Applications for the program will open soon. You can find more information here. Thank you so much to the crew of NOAA Ship Bell M. Shimada, the EXPRESS Scientists, and the NOAA Teacher at Sea program for this opportunity. What an incredible experience!

July 18, 2018September 19, 2018

Meredith Salmon: Xtreme XBTs, July 14, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Geographic Area: Atlantic Ocean, south of Bermuda

Date: July 14, 2018

Weather Data from the Okeanos Explorer Bridge – July 14, 2018

Latitude: 28.58°N

Longitude: 65.48°W

Air Temperature: 27.4°C

Wind Speed: 13.96 knots

Conditions: Rain and clouds

Depth: 5183 meters

Science and Technology Log

Temperature and salinity are two main variables when determining the density of water. The density of water or any acoustic medium is a very important factor in determining the speed of sound in water. Therefore, temperature data collected by Expendable Bathythermograph (XBT) probes, as well as historical salinity profiles from the World Ocean Atlas, are used to create sound velocity profiles to use to correct for sound speed changes in the water column.

Expendable Bathythermograph (XBT) probes are devices that are used to measure water temperature as a function of depth. Small copper wires transmit the temperature data back to the ship where it is recorded and analyzed. At first, I was surprised to learn that temperature data is such an important component of multibeam mapping operations; however, I learned that scientists need to know how fast the sound waves emitted from the sonar unit travel through seawater. Since these probes are designed to fall at a determined rate, the depth of the probe can be inferred from the time it was launched. By plotting temperature as a function of depth, the scientists can get a picture of the temperature profile of the water.

On our expedition, we have been deploying XBTs on a schedule as the ship is making its way to the survey area. The XBT Launcher is connected to a deck box, which translates information to computer systems onboard so the data can be logged when the probes are deployed into the water. Aboard the Okeanos Explorer, up to 8 tubes can be loaded at one time and launched by scientists.

xbt 1 — Savannah and I after a successful XBT load

XBT Data from a launch aboard the Okeanos Explorer. The colors on the graph indicate the XBT number and the data is plotted on a temperature and depth scale.

In addition to launching XBTs and collecting data, we completed a Daily Product so that we can communicate the data we have collected to anyone on shore. The Daily Products are completed not only to ensure that the hydrographic software systems are working correctly but to also inform the public our current location, where we have collected data, and if we are meeting the objectives of the mission. Once onshore, NOAA uses this information to analyze the quality of the data and use it for analysis for dive planning. In order to generate the Daily Field Products, we use hydrographic computer systems such as QPS Qimera for advanced multibeam bathymetry processing, Fledermaus for 4D geo-spatial processing, and Geocap Seafloor for digital terrain modeling. In addition, the Daily Field Products allow us to double check the quality of the data and search for any noise interferences due to the speed of the ship or the type of seafloor bottom (hard vs soft).

Personal Log

One of the coolest parts of learning aboard the Okeanos Explorer is the fact that I am a part of scientific exploration and discovery in real time. Known as “America’s Ship for Ocean Exploration,” the Okeanos Explorer is the only federally funded U.S. ship assigned to systematically explore our largely unknown ocean for the sole purpose of discovery and the advancement of knowledge. This is the first U.S.-led mapping effort in support of the Galway Statement on Atlantic Ocean Cooperation and all of this information is going to be available for public use. Not only do I get the opportunity to be involved with “real-time” research, but I am also responsible for communicating this information to a variety of different parties on shore.

Being immersed in the “hands-on” science, learning from the survey techs and watch leads, and observing all of the work that is being done to collect, process, and analyze the data is a really exciting experience. I am definitely out of my element when it comes to the content since I do not have any prior experience with seafloor mapping, sonars, etc., but I am really enjoying playing the role as the “student” in this situation. There is definitely a lot to learn and I am trying to soak it all in!

Did You Know?

XBTs contain approximately 1,500 meters of copper wire that is as thin as a strand of hair!

Resources:

http://www.aoml.noaa.gov/phod/goos/xbtscience/news.php

https://oceanexplorer.noaa.gov/facts/xbt.html

July 31, 2013March 12, 2021

Julia Harvey: Listening to Fish/How I Spent My Shift, July 28, 2013

NOAA Teacher at Sea
Julia Harvey
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 22 – August 10, 2013

Mission: Walleye Pollock Survey
Geographical Area of Cruise: Gulf of Alaska
Date: 7/28/13

Weather Data from the Bridge (as of 18:00 Alaska Time):
Wind Speed: 15.61 knots
Temperature: 13.71 C
Humidity: 91%
Barometric Pressure: 1023 mb

Science and Technology Log:

How do scientists use acoustics to locate pollock and other organisms?

Scientists aboard the NOAA Research Vessel Oscar Dyson use acoustics, to locate schools of fish before trawling. The Oscar Dyson has powerful, extremely sensitive, carefully calibrated, scientific acoustic instruments or “fish finders” including the five SIMRAD EK60 transducers located on the bottom of the centerboard.

Trnasducer — Scientists are using the EK60 to listen to the fish.

This “fish-finder” technology works when transducers emit a sound wave at a particular frequency and detect the sound wave bouncing back (the echo) at the same frequency. When the sound waves return from a school of fish, the strength of the returning echo helps determine how many fish are at that particular site.

The transducer sends out a signal and waits for the return echo... — The transducer sends out a signal and waits for the return echo…

Sound waves bounce or reflect off of fish and other creatures in the sea differently. Most fish reflect sound energy sent from the transducers because of their swim bladder<s, organs that fish use to stay buoyant in the water column.

The above picture shows the location of the swim bladder. (Photo courtesy of greatneck.k12.ny.us)

Click on this picture to see how sound travels from various ocean creatures through water. (Photo from sciencelearn.org)

These reflections of sound (echoes) are sent to computers which display the information in echograms. The reflections showing up on the computer screen are called backscatter. The backscatter is how we determine how dense the fish are in a particular school. Scientists take the backscatter that we measure from the transducers and divide that by the target strength for an individual and that gives the number of individuals that must be there to produce that amount of backscatter. For example, a hundred fish produce 100x more echo than a single fish. This information can be used to estimate the pollock population in the Gulf of Alaska.

The trawl data provide a sample from each school and allow the NOAA scientists to take a closer look by age, gender and species distribution. Basically, the trawl data verifies and validates the acoustics data. The acoustics data, combined with the validating biological data from the numerous individual trawls give scientists a very good estimate for the entire walleye pollock population in this location.

echogram for krill — These echograms are similar to the ones produced when we trawled for krill. Krill have a significant backscatter with the higher frequencies (bottom right screens)

Personal Log:

How I spent my shift on Saturday, July 27^th?

When I arrived at work at 4 pm, a decision was made to trawl for krill. A methot trawl is used to collect krill.

Then we set to work processing the catch. First we have to suit up in slime gear because the lab will get messy. My previous blog mentioned not wanting to count all of the krill in the Gulf of Alaska. But in this case we needed to count the krill and other species that were collected by the methot trawl.

Counting krill — I needed my reading glasses to count these small krill.

How many krill do you think we collected?

Krill Sample — This is the total krill from the first methot trawl of the night.
How many are here?

Patrick, the lead scientist, put a few specimens under the microscope so we could see the different types of krill.

The collection of krill was preserved in formaldehyde and sea water. It will be sent to Poland for further species diagnosis.

preserving krill — Scientist Darin Jones preserves the krill for shipment to Poland.

As the ship continued back on transect, I wandered in to see what Jodi and Darin were doing with the data collected last night. Jodi was processing data from the multibeam sonar and Darin was surveying the images from the drop camera. Jodi was very patient explaining what the data means. I will write more about that later. But I did feel quite accomplished as I realized my understanding was increasing.

multibeam data — These images are what Jodi was processing.

A decision was made to do another methot trawl. This time we had a huge sample.

In an approximately 50 gram sample we counted 602 individual krill. Compare this to the 1728 individuals in a 50 gram sample from the first trawl. They were much bigger this time. The total weight of the entire sample of krill was 3.584 kilograms.

How many individuals were collected in the second trawl? (Check your answer at the end of the blog)

Around midnight, Paul decided to verify an echogram by trawling.

trawl net haul — Emptying out the trawl net right next to the fish lab.

We collected data from the trawl net and the pocket net.

This trawl had a variety of specimen including Pacific Ocean perch, salmon, squid, eulachon, shrimp and pollock.

The pocket net catches the smaller organisms that escape through the trawl net.

pocket trawl — These were caught in the pocket net.

It was after 2 am by the time we had processed catch and washed down the lab. The internet was not available for the rest of my shift due to the ship’s position so I organized my growing collection of videos and pictures.

I wasn’t sure how I would handle my night shift (4 pm to 4 am) after I dozed off during the first night. Now that I have adjusted, I really enjoy the night shift. The night science team of Paul, Darin and Jodi are awesome.

Did You Know?

People who are on the Oscar Dyson live throughout the United States. They fly to meet the boat when they are assigned a cruise. Jodi is from Juneau, Alaska. Paul is from Seattle, Washington. And Darin is from Seattle/North Carolina. There are a number who are based out of Newport, Oregon.

Something to Think About:

When we are fishing, a number of birds gather behind the boat. What different sea birds are observable this time of the year in our survey area?