NOAA Teacher at Sea: Karen Matsumoto
Onboard NOAA Ship Oscar Elton Sette
April 19 – May 4, 2010
NOAA Ship: Oscar Elton Sette
Mission: Transit/Acoustic Cetacean Survey
Geographical Area: North Pacific Ocean; transit from Guam to Oahu, Hawaii, including Wake Is.
Date: Friday, April 25, 2010
Science and Technology Log
The Oscar Elton Sette is making its way to Wake Island, and we hope to be there by tonight. One of the research operations is to recover a HARP (High-frequency Acoustic Recording Package) that is in place on Wake Island and replace it with a new HARP unit.
This morning, I was on “CTD duty” at 4:30 a.m. A CTD (conductivity-temperature-depth) station is deployed prior to the start of the visual survey effort, right at sunrise. The CTD data is collected using the ship’s SeaBird CTD shown below. The CTD is deployed to a depth of 1000 meters (depending on depth where we are) with a descent rate of about 30 meters per minute for the first 100 meters of the cast, then at 60 meters per minute after that. It takes three people, plus a winch driver to deploy the CTD, as well as the expert operation from the bridge to keep the ship steady and in one place during the entire operation!
Background on CTDs
The CTD is a device that can reach 1,000 meters or more in depth, taking up to five water samples at different depths, and making other measurements on a continuous basis during its descent and ascent. Temperature and pressure are measured directly. Salinity is measured indirectly by measuring the conductivity of water to electricity.
Chlorophyll, a green photosynthetic pigment, is measured indirectly by a fluorometer that emits purple light and measures fluorescence in response to that light. These measurements are made continuously, providing a profile of temperature, salinity, and chlorophyll as a function of depth. The CTD unit is torpedo-shaped and is part of a larger metal water sampling array known as a rosette. Multiple water sampling bottles are often attached to the rosette to collect water at different depths. Information is sent back to the ship along a wire while the instrument is lowered to the depth specified by the scientist and then brought back to the surface.
By analyzing information about the water’s physical parameters, scientists can make inferences about the occurrence of certain biological processes, such as the growth of algae. Knowledge like this can, in turn, lead scientists to a better understanding of such factors as species distribution and abundance in particular areas of the ocean.
I am continuing my acoustic work with the sonobuoys. Today I heard a Minke whale BOING! Below is what a Minke whale boing looks like on the computer. It sounds very much like someone blowing a low tonal whistle or a cell phone vibrating on the desk!
To hear an Atlantic minke whale call (which is different from those found here in the North Pacific, but really cool!) go to this website:
http://www.pmel.noaa.gov/vents/acoustics/whales/sounds/sounds_atlminke.html
Personal Log
I am making so many great friends among the Sette crew and the science team! I am getting spoiled from all the fantastic meals put together by Randy our cook, and no one ever wants to miss a meal! Our wonderful Doc Tran makes incredible Vietnamese dishes and delicious desserts. Today we had cream puffs for dinnertime dessert! Who would have ever guessed!
Marie Hill, our Chief Scientist and fearless leader was awarded the prestigious NOAA Team Member Award! We surprised her with balloons and decorations in her cabin, and Doc Tran and Lisa made a yummy cake in celebration! Congratulations Marie!!!
We had a visitor today on the flying bridge-an exhausted juvenile red-footed booby! He sat on the mast, finding a place to rest in the middle of the ocean! It felt great to feel the warm wind hit my face and watch the sapphire blue water crash against the bow of the ship! What a great feeling!
Question of the Day: How can you figure out how much food to bring on a 2-week cruise? How do you keep the food fresh? What do you do with leftovers?
This is the situation that the Chief steward has to deal with on every cruise! How would you figure this out? Can you do the math?
New Term/Phrase/Word of the Day: Beaufort Sea State is an empirical measure for describing wind speed based mainly on observed sea conditions. It is also called the Beaufort Wind Force Scale. We stop conducting our visual observations when wind/sea conditions reach Beaufort 7, as wind and sea conditions are too rough to accurately make observations (and its windy out there!).
Something to Think About:
This part of the North Pacific is often described as an ocean desert. We have not seen any whales, and have had only a couple sightings of dolphins since we left Guam. We have also seen migrating sea birds, but not in huge numbers. What do you think may account for the lack of sea life in this expanse of tropical waters?
Animals Seen Today:
- Sooty tern
- Red-footed booby (juvenile)
Did you know?
That the team of whale visual observers never discuss the numbers of animals they see among themselves. Some people consistently count high, others count low, others are spot on! By not discussing how many animals they observed, they don’t influence each others’ observations. Back at the lab, researchers compare each observer’s counts from their written observations, and can tell which observers tend to under or overestimate numbers of animals they see. They can then make adjustments to total numbers based on everyone’s observations! This is similar to calibrating thermometers or other scientific equipment!
