Sunset sampling!

Last night we made our first MOCNESS tow! The MOCNESS, Multiple Opening Closing Net and Environmental Sensing System, is an oceanographic instrument which allows us to collect small organisms from different layers of the ocean. There are 9 nets; when the net leaves the deck it has net 0 open, and net 0 stays open as we lower down to near the seafloor. Then, when we are as deep as we want to sample, up in the lab on the ship we click a button to “step net” and that makes a bar move which closes net 0 and opens net 1. As we slowly bring the net back to the surface, we step the net at certain depths, for example 400 meters, 300 meters, 200 meters, etc., so by the time the instrument gets to the surface we have collected separate samples for each different depth in the water. It’s pretty cool, and it helps us to understand which animals live where in this 3D environment, and how they move up and down at different time.

As is to be expected with a complicated instrument, the first tow wasn’t perfect. The nets didn’t close quite when we clicked the button, and the little propeller that tells us how much water went through the net (important if you want to know how many animals live in each amount of water) was little off too. So we brought it back on board, and our Electronics Technicians (ETs) Gabby and Aedina, gave it some TLC. An hour later we tried again, and now everything is working great! We caught quite a few copepods, and some amphipods and are looking forward to more tows in the coming days!

As were MOCNESSing a couple of times, it was getting late, by the time we were done it was getting close to 2 am. But it never got dark! Down here at 64 South, the sun doesn’t go far below the horizon at night in summer. It got dusky after about 11:30, and around midnight the sky was a beautiful pink sunset (see the picture from Michelle). But then the sunset just stayed for an hour or so and morphed into sunrise! By the time I crawled into bed around 2 it was starting to get brighter out again!

Categories: Musings of an Oceanographer | Leave a comment

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