NOAA Teacher at Sea
Aboard NOAA Ship Bell M. Shimada
March 13-18, 2015
Mission: Channel Islands Deep-Sea Coral Study
Geographic Area: Channel Islands, California
Date: March 16, 2015
Day 4: Monday 3/16/15
The visiting sonar technician left this afternoon on NOAA’s Shark Cat boat after working diligently to fix the ship’s sonar system throughout the past few days. As of now, the ME 70 sonar is up and running. This equals exciting news for the sonar team that has been waiting patiently to begin their projects. The Shimada actually has two sonar machines; one works with a single beam, while the other, the ME 70 has multiple beams that can cover a much greater amount of territory in the same amount of time.
How does sonar work?
Sonar technology is a way for us to create images of what is below the surface of the ocean. The sonar system, which is attached to the bottom of the ship, sends out an acoustic signal towards the ocean floor and then measures how long it takes for the sound to bounce back to the boat. By measuring this, the sonar creates a picture of the depth of the ocean floor in that area.
A secondary measurement that is also occurring when the sonar machine is running is called backscatter. Backscatter measures the intensity, or loudness, of the sound as it echoes back to the ship. The softer the sound when it reflected back means the softer the type of surface it is bouncing off of, such as sand. The louder and more severe the sound is equates to a harder surface floor, such as rocky ledges. As Andy explained to me, think about bouncing a ping-pong ball on a carpet vs. hardwood floor. The ping-pong ball will have a much stronger bounce off of a hard surface v. a softer one. Will also explained that based on the backscatter sound we can determine fine details such as whether the sand is fine or coarse.
Both of these sonar features create an image of what the ocean floor looks like, its physical features, habitat types and any potential hazards that may exist below the surface. This is critical for creating nautical charts and it is also important for the navigation of the ROV, so it doesn’t stumble upon any unexpected obstacles while traveling underwater.
Another feature that sonar is used for on this ship is to measure fish abundance. The sound waves travel down and bounce off of the fishes’ swim bladders. Swim bladders are gas filled bladders found in many fish that helps them stay buoyant. Using this method, scientists could use sonar to gauge fish populations, instead of catching fish to see what is out there.
So far in the trip, Laura Kracker and her team (Mike Annis, Will Sautter and Erin Weller) have been using the working sonar to map fish populations in the area. Tonight, however, they will use the ME 70 for a test run to map out areas of the Channel Islands National Marine Sanctuary that have never been mapped before! This data could be used to create brand new nautical maps, to help scientists have a better idea of what the hidden part of our sanctuary looks like and to determine which regions might be best habitats for fish or coral. Tomorrow, the ROV team will send the ROV to the sites that were mapped the previous night to check out features that were discovered on the seafloor and to explore the newly mapped regions.
Life at Sea
When setting out on this journey, students asked me what life would be like living on a ship. I spoke with several of the crew members on the ship about what it is like to be out at sea for days at a time. So here is an image of what it has been like so far, from the perspective of some of the crew and from my own experiences:
The Bell M. Shimada is an enormous ship, over 200 feet in length. I have been here for four days now and still have not explored the entire place! The ship is approx. six stories tall, though on the ship they refer to the different levels as decks, not stories. The Shimada is run from a platform on the third deck, known as the bridge. The steering of the ship takes place from the bridge and there is always an assigned lookout person, whose job is to look out the windows to see what is going on around the ship. The bridge is also equipped with radars that can detect boat traffic or other obstacles.
A lot of communication goes back and forth between the scientists in the ROV command room and the bridge. The bridge must ensure that the ship stays steady and follows the ROV during its dive. If the ship moves too much it can yank the ROV around or the cables from the ROV could get caught or damaged under the ship.
The areas where we sleep on the ship are called staterooms. Almost all of them consist of bunk beds and have a toilet and shower area. I am rooming with Erin, one of the scientists working on the sonar mapping project. Erin and her team work during the night after the ROV runs, so typically she is going to bed shortly before I wake up for the day. We have both been working hard to stay quiet enough to let each other catch up on our sleep!
The Shimada has many features that I was not expecting on a ship, such as an exercise room equipped with treadmills and weights. We even have Internet access here! Another unexpected feature is the lounge/ theater room that is across the hall from my stateroom. It has plush reclining chairs, a huge flat screen TV, and all the DVDs you could ever hope to watch, including the newest movies.
When talking with the crew about what they love most about their jobs, many of them referred to how being part of a NOAA boat allows them incredible travel opportunities. One person I spoke with has been to 52 different countries throughout his career with NOAA! Another benefit of a maritime career such as this is that NOAA pays for part of your education. It requires special schooling and credentials to be able to be an engineer or commanding officer on a ship, and NOAA helps offset those costs. One of the biggest challenges of the job, however, is being away from family and friends for such long periods of time. Some of the crew explained to me that they may be out at sea for 30 days at a time, sometimes even longer.
One great perk to life aboard is the food. Two chefs prepare all of the meals on the Shimada for us. Similar to our lunch time at school, the meals are served at the same time each day in what is called the mess hall. If you oversleep and miss breakfast, not too worry; there is cereal and other snacks available around the clock. They serve breakfast, lunch and dinner on the ship, and we have even had the treat of fresh salads and homemade desserts!
The ship stays running smoothly thanks to the help of the engineers and crew members. They work behind the scenes around the clock to keep the ship afloat.
My absolute favorite location on the ship is called the flying bridge. It has 3 tall chairs that look out over the ocean and an almost 360 degree view of the sea. The chairs have been used on previous excursions for scientists to sit and count marine mammals as part of their survey. It is a great place to watch the sunset from.