TRASNA Blog – Day 8

TRASNA Blog – Day 8

Written by:
Peter Macintosh
Undergraduate At Memorial University, Canada

May 19, 2016
Latitude 53°00’
Longitude 15°49’
1924 UTC
Wind SW @ 15 Knots
Air Temperature 13°C
Sea State 1.5 M

The weather was beautiful today, I believe it was the nicest day we had on the trip so far. Our plans for today were to conduct a CTD test which stands for conductivity, temperature and depth but also can be used to test numerous other water characteristics. The plan for today is to test in the CTD in the morning and then later collect and do maintenance on a couple of weather buoys in the area.

CTD Test

We began running the CTD test around lunch time, we were running the test in water depths of 3600m. At this depth it takes one hour after the CTD is launched from the boat for it to reach the bottom, after that it takes another hour to retrieve it. During our test we recorded temperature of 10-2.5 °C a sound velocity of 1498m/s and a salinity of 34.964ppt. Tomorrow if the weather continues to be mild we will likely conduct a type of seismic test that is called a sparker. This test consists of firing 4000 volts of electricity between four electrodes. This electricity creates a imploding bubble under the water that creates a bubble that implodes, in turn sending out soundwaves into the water. These soundwaves penetrate the sea floor and return to hydro phones which read the sound waves. In ideal condition this sparker test would  allows us to penetrate the sea floor up to 200m. The seismic data recorded from the sparker will allow us to see important geological factors such as fracture zones and different stratigraphic layers in the sea floor.

The afternoon consisted of retrieving a marine weather buoy which was in need of repair. Marine weather buoys are very important for meteorologist because they provide them with current sea conditions such as wave height, temperature and wind speed. Meteorologists can then use this data to create weather models which help predict future weather conditions. The weather buoy that we are retrieving today will be completely taken out of the water and returned to shore so that it can be cleaned and repaired. Retrieving the weather buoy is quite a big task because the buoy itself is about 8meters tall and has 4500 meters of rope attached to it which is then held on the bottom by a three ton weight. The capture and removal of the buoy itself went off quite smoothly and took no more than 20 minutes thanks to the well trained crew and smooth weather. Then it took about an hour and a half to wind in all of the rope from the seafloor and store it on the ship.

Weather Buoy