3 Days In

Today is our 3rd  day at sea; we’ve spent our time finalizing the set-up and practicing for the first “real” event which starts on Monday. A majority of our seawater samples will be collected on “stations”, which is where we stop the ship at a pre-selected latitude and longitude and deploy various bottles and sensors over the side to collect samples and data for us. 

One example of a sensor is the CTD – which stands for Conductivity, Temperature, and Depth. [Conductivity tells us how salty the water is.] All of the data that this sensor measures is recorded on shipboard computers in real-time.


This is a “rosette” which has both a CTD (within the yellow cage) and 12 sampling bottles on it.

The large grey bottles shown above are used to collect seawater. A pressure trigger detects when they are below the surface of the water and pops their tops and bottoms open. Then, the long steel cable attached to the rosette lowers it to the depth we want and somebody sitting in front of a computer (on the ship) controls when the bottles snap shut. Each bottle can be closed at its own individual depth. 

Once the rosette is back on deck, scientists collect water from each large bottle for analysis in the lab. For example, the major nutrients, nitrate and phosphate, are measured (right here on board the ship!). Each complete cycle of deploying and recovering a piece of equipment is called a cast, and they can take anywhere from 1 to 10 hours to complete, plus additional time to sample their water into every scientist’s bottle(s) once on board.

 
Gretchen and Nick enjoying our transit between practice stations. The South Pacific weather has been fairly cool, overcast, windy, and humid so far.