NOAA Teacher at Sea
Jillian Worssam
Aboard NOAA Ship Miller Freeman
July 5 – August 1, 2004
Day: Six
Sunday July 11th, 2004 23:52
Longitude: 59° 32 Sea Wave Height: 2′
Latitude: 173° 51 Swell Wave Height: 2-4′
Visibility: 1.5miles fog Sea Water Temperature: 9.9C
Wind Direction: 221. Barometric Pressure: 1012 high pressure
Wind Speed: 9.1 kts Cloud Cover: complete 100%
Haul Data: CTD (conductivity / Temperature / Depth)
Depth of haul: 90 meters
Temperature at depth: 10° C surface – 2° C at bottom
Species breakdown: Informational gathering / no species collection
Science and Technology Log:
The CTD is a device that is hard to explain. Scientific in nature similar to an inverted cone that has a six inch diameter at the top. Today we will look at the condition of the water, the liquid habitat for this ecosystem. Conductivity will give the scientists, with some calculations, the percent of salt in solution. This is important information as the salinity affects the density of the water which in turn affects the speed of sound. Knowing the speed of sound is vital in acoustic fisheries surveys as the scientists use back scatter data in determining fish location and density. The density of water is also affected by the salinity and temperature of the water.
Today’s temperature at 90 meters was 2°C, at the surface it was a balmy 10°C. Ocean water like our atmosphere is in layers, each a distinct unit. The thermo cline was at 35 meters, with a graphic representation showing a distinct differentiation between the two water masses.
The CTD data is used in looking at correlations between where fish populations are found and if their placement is not only affected by the condition of the water, but if there are conditions that they prefer.
Personal Log:
Understanding the CTD has been difficult for me. This ecosystem is literally poles apart from a ponderosa pine type forest. I am learning an amazing amount of information and at the same time realizing how much I do not know. Oceanography is an amazing science, and phenomenally diverse.
Once again I spent an hour on the bridge, 2400-0100, standing watch. I did not realize that this nautical term is in fact correct as there are no seats on the bridge except the CO’s chair which is off limits. I was told that there is a common yarn that the captain’s chair is directly above his stateroom, and attached to a bell. If someone sits in the chair the bell will ring indicating that sacred territory has been breached. When a person stands watch for four hours, they stand watch. There are some counters with cushions to brace against, but that is it. While standing watch last night I got my first glimpse of a dall’s porpoise. The pictures that are commonly seen of porpoises show the entire animal usually gliding gracefully with a wave. Our view last night was a glimpse, a peak into the life of a marine mammal. It was Mark, the field operations officer who first spotted the sign, a brief splash within the bow wave of the boat. The porpoises travel the wave of a boat, literally catching rides. At one time there was the splash of three heads effortlessly coming up for air, a brief splash and again they were lost in the wave only to be seen moments later literally in the same place even though we were all moving forward.
There is a calmness here when the fog moves in, a sense of peace. We are out of touch with time, yes there are news briefs, but one does not need to read what is going on in other places. I am ok with the solitude, the sound of the engine the gentle rocking of the boat. This is a serene place to be, in summer!
