Science on Deck

Last night I went to sleep and the boat was rocking and rolling. The wind was blowing more than 40 knots and waves were crashing over the main deck. When I woke up this morning it was dead calm. It felt like the ship wasn’t even moving. I had to go look out the window to check.

We were completely surround by soft slushy pancake ice  that quieted the waves and rolls right down. It newly formed first year ice,  so very easy for the ship to travel through.   The ice stayed parted after the ship passed, leaving a nice wide channel to deploy the research gear.

To catch zooplankton (small animals that float or weakly swim in the water column) we use a big winch to lower a very fine mesh net into the water. The net is pulled behind the boat for about a half and hour, before it is retrieved. We  do this about 6 times a day.

To prevent ice crystals from forming and blocking the net’s mesh, the net is stored in a heated container. It is then carried out onto the deck under the winch. The net weighs about 100 lbs, so it can be a bit awkward to move.

One of the main purposes of this cruise is determine how many of each zooplankton species live in the study area. To do that you need to know how much water was sampled, or passed through the net. The net has a current meter attached to it. It counts rotations of the propeller which is proportional to how much water went into the net.

The net will be lowered to about 170 meters,  left to stabilize for about 30 seconds and then slowly brought to the surface. We try really hard to avoid the ice- which can freeze and crush all the little critters in the net.

Once the net is back on board we hose it down to make sure all the zooplankton are gathered in the back or cod end of the net. For our net, the cod end is PVC pipe.  It gets a bit brittle in the cold Antarctic waters. If it hits the boat, it could shatter and release the catch. We protect it with foam and duct tape.

Krill and other critters get stuck in the mesh, so we hose it down to get our full catch.

So that’s how we get our samples. Now into the lab where we can see what we got.