Week 3 Cruise Update

Efficiency at sea – practice makes perfect

April 7, 2021

A20 Weekly Cruise update #3

This last week has been one of pleasant routine. We’ve become a well-oiled machine of prepping
the CTD rosette, deploying, recovering and sampling the rosette, and steaming to the next
station. Wash, rinse, repeat. The weather has been beautiful; generally sunny with temps in the
70’s. The waters are calm and clear, with the CTD visible down to about 20m. The good weather
and smooth operations have allowed us to maintain 35 nm spacing between stations.

As tradition dictates, at the deepest station (43) we secured a mesh bag filled with Styrofoam
cups, decorated by scientists and crew, to the rosette and sent them to the bottom of the ocean.
Going to a depth of 5850 m the bag, nearly overflowing when it entered the water, came back
less than a quarter full. The great pressure from that depth forcing all the air out of the Styrofoam
and shrinking the cups (fig 1).

Europa being shown prior to launch

Figure 1a. Before photos of the decorated Styrofoam cups.

First float profile

Figure 1b. After photos of the decorated Styrofoam cups.

Over the last week we’ve covered ~14 degrees of latitude and are now firmly within the tropics.
To enjoy the warm sunny weather, we had a Sunday barbeque on the back deck allowing for a
welcome break from the routine we have become accustomed to. During the last several stations
Mahi-Mahi and other fish have been observed swimming around the ship.

We’ve made swift progress on the transect, and there now remains only about a week left of
science before we turn north west and head into port.

Ryan Woosley – Chief Scientist
Andreas Thurnherr – Co-Chief Scientist

Stations

SOFAR Drifters

BGC-Argo Floats

Core Argo Floats