NOAA Teacher at Sea
Aboard NOAA Ship Okeanos Explorer
March 16-April 3rd
Mission: Caribbean Exploration (Mapping)
Geographical Area of Cruise: Puerto Rico Trench
Date: March 19, 2015
Weather Data from the Bridge: Partly Cloudy, 26.7˚C, waves 1-3ft, swells 2-4ft.
Science and Technology Log:
This morning at breakfast Commanding Officer Mark Wetzler, or CO, explained that we would be deploying instruments today. The first one was a glider for the Navy. The Slocum electric glider is like a tiny, unmanned submarine built like a non-explosive torpedo with small wings. It has the ability to be remote-controlled for weeks to months at sea operating 24 hours a day even in the worst weather. They can be programmed to travel back and forth, dive, and rise periodically to communicate data back to the mainland and accept new missions. These autonomous underwater vehicles (AUVs) can collect many different types of data such as temperature, conductivity, or audio recordings, depending on the sensors attached. Gliders like this one can help detect tsunamis or other changes in the ocean.
Our vessel also records data 24 hours a day but is limited in its duration at sea by the needs of the people and fuel onboard. Have you wondered how we can stay out at sea for nearly 3 weeks at a time without hitting the grocery store or service station? I’ll explain more about that in a future blog.
The next deployment was a test run of a “free vehicle.” Dr. Wilford “Bill” Schmidt, and his assistants, Rolf-Martin Vieten and Zamara Fuentes from the University of Puerto Rico, Mayguez (UPRM) are testing the design of vehicles that can be deployed from a vessel like the Okeanos Explorer or a smaller ship. These vehicles are inexpensive to make, easy to deploy, and do not need to be tethered to the ship. They can be programmed to dive to the deepest parts of the ocean, or whatever depth desired, in order to take samples or record data. Once the vehicle has completed data collection or sampling, it releases its anchor and rises the surface where it is retrieved. Meanwhile the deployment vessel can continue other operations such as mapping. Time is not wasted on a research vessel! On this cruise they will use the device to sample the conductivity, temperature and depth of the water column. This will help them learn more about the interaction between different water masses in the Puerto Rico Trench.
Water masses in the trench are of particular interest to Bill, a professor of physical oceanography, because they could hold a key to understanding the flow of different ocean currents. He explained that water masses form at the surface at a particular temperature and with a certain salinity corresponding to the surface conditions at the time. Temperature and salinity are conservative properties, meaning they don’t change as the water mass moves. So as a water mass formed in Antarctica sinks and moves toward the deepest parts of the ocean due to its density, its cold temperature and salinity don’t vary significantly. So temperature and salinity can serve as fingerprints of water masses. Therefore as he measures these factors through the entire water column in the trench, we would expect to see the values change as we move from the North Atlantic Deep Water to the Antarctic Bottom Water. The image below shows a generalized representation of the typical flow pattern of large water masses.
Bill’s work is supported by NOAA and the National Science Foundation. The NOAA Office of Exploration and Research recently provided him with an award to produce 5 free vehicles with his university team. The fact that Bill’s vehicles are able to travel untethered into the hadal zone at a very low cost makes them uniquely valuable to researchers. Data from the hadal zone is virtually non-existant because only enormous vessels would be able to support winches that could handle the 10,000+ meters of cable that would be required for the tethered vehicles currently used. Since the average depth of the ocean is only 4000m, there is not a large enough demand to make manufacturing such large winches economically feasible.
Also, Bill’s free vehicles are small and can be deployed on very short notice, allowing them to capture data as major events occur. The vehicles can carry interchangeable payloads that could be used in all scientific disciplines. A biologist could request water or bottom substrate samples to examine life forms in the hadal zone that may not exist elsewhere. A geologist might also like to sample the bottom substrate or might wish to record seismic activity at the bottom of the trench to better understand plate interactions. A chemist interested in oceanography could examine the water for trace elements or compounds that were emitted into the air at one point in time, such as chloroflourocarbons (CFCs) that were once used but are now illegal in the US due to their impact on the ozone layer, or tritium (H-3) remnants from nuclear bombs used in WWII. This could provide us with an estimate of how long ago the water mass was at the surface and help us determine the rate of flow into the trench. The research possibilities are endless.
Initial tests looked good. During our 19 day voyage, Bill’s team and the crew will deploy the vehicle up to 11 more times with up to 6 locations strategically placed in the Puerto Rico Trench.
Are you interested to know what the accommodations are like aboard the Okeanos? They are comfortable enough for a work boat. Take a look for yourself!
I love the curtain around my bottom bunk. It reminds me of the forts my brothers and sisters and I built as kids. I have slept like a baby ever since arriving. The rocking of the boat is very calming.
There are a couple of nice spots to relax and chat, and write in my blog. Here are the library and the lounge.
I am surprised that I really haven’t been seasick. Motion sickness medication really helps. If you really get sick, there is a medical officer on board and sick bay.
I showed you the galley in the last post. We eat in the Mess Hall. The Chief Steward puts tennis balls on the bottom of the chairs to avoid scratching the finish on the floor. Good thinking!
And when I have eaten too much, there is the fitness room! There is a scale in the fitness room, but when you stand on it, the action of the boat rocking causes the scale to oscillate by 30-40 pounds. It is a great demonstration of the difference between mass and weight!
The best place to hang out is outside, of course, where you can possibly see a spouting whale or swimming dolphin. I have seen both on this trip already but I need to be quicker with the camera! Maybe next time!!
Question of the Day: