Nancy Lewis
Onboard NOAA Ship Ka’imimoana
September 15 – 27, 2003
Mission: Tropical Atmosphere Ocean (TAO)/TRITON
Geographical Area: Western Pacific
Date: September 23, 2003
Sunrise: 0608
Sunset: 1815
9/22/03~2330: 6 N CTD
0615: 7N CTD
1300: 8N CTD
2000: Repair 9 N Buoy W/ CTD
Weather Observation Log
Latitude: 7 Degrees, 25.3’ N
Longitude: 140 degrees, 8.0 W
Visibility: 12 nautical miles (nm)
Wind direction: 170 degrees
Wind speed: 10 knots
Sea wave height: 3-4 feet
Swell wave height: 4-6 feet
Sea water temperature: 28.5 degrees C
Dry bulb pressure: 30.4 degrees C
Wet bulb pressure: 26.3 degrees C
Cloud cover: 5/8, Altocumulus, cirrus
Air Tempterature: 30.4 degrees C
Science and Technology Log
Previously, I explained that there is other scientific work being done on this cruise. One such project is CO2 and pH analysis. Previous to this, NOAA has been using water samples taken from the CTD, and these samples only come from particular depths, generally every 200 meters. The scientists from the University of South Florida have brought along devices which they are testing in order to work out the “bugs”, from these prototypes. They are called SEAS systems, and are lowered in the water column to a depth of 300 meters at a rate of 6 meters per minute to collect pH profile continuously. The advantage of the SEAS system over taking samples from the CTD is that they get a continuous data, not just data from the specific depths tested by the CTD. The data they produce is therefore much more complete and accurate.
In my interview with Dr. Renate Bernstein I asked the question: “Is your work related to studies of global warming?” Her answer was: “absolutely. “ The SEAS system is analyzing dissolved CO2 in the ocean water. Normally, the ocean is considered to be a “sink” for CO2 in the atmosphere. Cold water has the capacity to dissolve more CO2 from the atmosphere than hot water. The analogy would be to think of the carbon dioxide in a carbonated soda. If you shake up a cold drink, it doesn’t fizz as much. If you do the same thing with a warm soda, it will fizz up much more.
How does dissolved CO2 relate to the pH of the ocean? The carbon dioxide combines with water (H20) molecules in the ocean to produce carbonic acid, which has a higher acidity. Thus water with more dissolved CO2 would have a higher pH value.
Dr. Bernstein explained that there are areas, however, where the ocean is liberating CO2. She said that was what they were seeing from the data they’ve collected. The water near the equator where cold water upwelling occurs were the places where CO2 was being diffused into the atmosphere. According to Dr. Bernstein, what they were doing on board this vessel was truly “cutting edge science” being done nowhere else in the world. It has been exciting to me and a great honor to share with you some of the science being done on board the KA’IMIMOANA.
Personal Log
For the first time on this cruise, the weather has become hot and humid. It was not a pleasant day to be out on the deck of the ship, plus they were power washing the deck and acid cleaning the sides of the vessel. Last night I was out with my Planosphere, trying to identify some constellations, but the clouds had started, so visibility was not that good. I did see Sagittarius, which looks like a teapot. Randy, the Survey Tech in charge of the CTD, showed me a computer program that I want to get called “Starry Night”. You put in your location and the time and date, and it shows the night sky and superimposes images over the constellations: very cool!
I almost missed the biggest event of the day, and for me, of this, cruise. John Kermond had told me that the buoy repair was cancelled, so there wouldn’t be a last RHIB ride out to the buoy. I had already prepared for bed, when there came a knock at the door. “ Hurry up, they’re going on the RHIB!” I quickly scrambled on some clothes and ran up to the deck, while Doc hunted up a hard hat and life jacket for me. They strapped a Cyalume light onto my vest, John gave me a flashlight, and we were off. I felt a little like what it must have been like on the Titanic, getting into lifeboats in the inky blackness. We roared off, using a powerful light to see the buoy. The water around the buoy was teeming with large fish, mostly mahi.
This buoy had been damaged and Patrick Ahearn, the Chief Scientist would be making the necessary repairs. Sometimes, they say, other ships hit the buoy, or fishing boats tie up to the buoy. This was the first time the sea had been relatively calm, and it seemed a good thing, since higher seas would make a repair job much more difficult, like working on a bobbing cork. Patrick swung out onto the buoy, follwed by Nicole Colasacco, the Field Operations Officer who would assist him.
In the meantime, we sped back to the KA to pick up replacement instruments, a new rain gauge, a new anemometer, and a new temperature sensor. The ship seemed a long way off, but all of its running lights were on. I thought about how it must have felt for Patrick and Nicole to be all alone in the dark on that buoy while we went back to the ship.
As soon as we returned with the instruments, Jimbo set out fishing lines and we bagan to troll. We spent a good 45 minutes circling the buoy, but got nary a bite. Maybe it just wasn’t feeding time. As our eyes got our night vision, we could see the sparkling of bioluminescent creatures in the water all around the boat. The skies were cloudy, so stargazing was out, and eventually it began to rain.
Finally, they were finished with the repair job, and it was my turn to get out onto the buoy. I already knew that the donut would be slimy and slippery, and it was. There are several platforms, though, that afford good footing inside the bars of the instrument scaffold. By the time I was up on the buoy, the swells had picked up a little, and actually, there was a terrific current pulling on the buoy. It was a little like riding a bucking bronco!
We were out on the buoy operation until well past 11 last night, but I was so glad I hadn’t missed my last chance to get on one of the buoys. The fish weren’t biting, so we came away empty handed, but they’ll be other fishing opportunities as we start the long transit back to Honolulu. Since we have to go right past South Point on the island of Hawaii, there is a chance that students from my school may get to see us, and I’ll keep you posted on exactly when that will be.
Question of the Day: What is the chemical formula for carbonic acid?
Aloha from the KA!
Nancy Lewis