Surface Mooring Deployment

We are underway, and made it out of Icelandic waters a couple of days ago. Neither of us have been too seasick, and we are starting to get our sea legs.

Today is an exciting day aboard the Armstrong because we deployed the surface mooring this morning! The surface mooring is essentially a giant buoy with a variety of instruments on it that can make measurements in the water and air. It is powered by a combination of solar and wind power, which allows OOI to collect measurements year-round to better understand this remote area.

In this photo the crew lowers the top buoy of the surface mooring into the ocean

There is a wide array of instruments on the mooring. The top of the surface mooring has different instruments that measure different properties of the atmosphere, which we can later use to compare with these properties in the water. Seven sensors make meteorological measurements, such as wind speed, which help give a better sense of the weather in the area, but could also help inform scientific observations, for example relating a specific phenomenon to a storm. There are also satellites, a GPS unit, and a SBD (a device that receives email message commands) all of which help OOI communicate with the surface mooring and know where it is. It also has a camera on it, which can help engineers understand how their equipment is fairing and the current conditions in the Irminger sea.

Stephanie Petillo, OOI SGSN software lead, explaining different instruments on the top part of the mooring. Most of the instruments are attached to the two 'halos' on the tower of the mooring.

Moving down to the lower part of the buoy there are a lot of different instruments to measure different properties of the water. Most of the instruments that are on this part of the surface mooring measure the exact same things we have been looking at in our lab. The surface mooring has a fluorometer, which measures chlorophyll and backscatter, a SUNA, which measures the amount of the nutrient nitrate in the water, and an oxygen optode, which measures the amount of dissolved oxygen. Additionally, there is a spectrophotometer, which shines a beam of light across a small area of water, and uses the absorption and scattering of different wavelengths to see what is in the water. There is also a pCO2 sensor, which also has a tube going to the air, so we can measure the difference in CO2 between the air and the sea.

Stephanie explaining different instruments on the bottom part of the mooring. She also showed us ingenious engineering designs to help secure the mooring, but still allow it to move with the ocean.

From the buoy there is a long cable that goes all the way to the sea floor! Along this cable there are a couple of key instruments attached. Between 130 m and the surface, the cable has a fluorometers, oxygen optodes and a pCO2 sensors attached onto it in cages. Additionally, CTDs are attached intermittently between the surface mooring and 1,500 m. CTDs are one of the most important oceanographic instruments, they measure conductivity, temperature, and depth of the water they are in. Later on in the cruise, we will send a CTD down to the bottom of the ocean so that we can compare the profile from the surface mooring to that data. At the very bottom of the cable are 72 glass balls which will be released from the anchor at the very bottom to retrieve all of the instruments along the line next year.

Here we are helping hold CTDs to attach to cable.

The surface mooring is an incredibly important instrument in this array because it is the only mooring that has instrumentation that measures the air, and the only mooring that has power. This allows it to measure many more aspects of the region that other moorings cannot, giving us a more precise understanding of what could be changing different variables in the region.

A picture of us with the surface mooring!

Until next time!
-Claire