Zooplankton and madness

Thursday, November 12th was the last day of science operations onboard the Amundsen. We were all over the ship, helping out where we were needed and sometimes hanging out where we weren’t. After supper we all went out on the front deck to see the nets being deployed. The lowdown on zooplankton nets:

Horizontal net : 2 large nets and one small. Takes zooplankton samples from one layer in the water column, is pulled horizontally through the water (go figure).

Vertical net : 4 large nets and one small. Collects zooplankton the entire length of the water column, is lowered to the bottom and then pulled up (vertically).

Hydrobios net : 9 nets which can be deployed independently at various depths.

Rectangular Mid-Water Trawl Net : Basically the same as the horizontal net, but collects larger organisms, and is bigger.

Each net has a different sized mesh to collect different sizes of zooplankton. Each net has a bottle attached to the end in which the sample is collected, so you end up with a high concentration of zooplankton in each sample bottle.

So there you have it; more than you ever wanted to know about zooplankton nets. Now join me in the zooplankton lab (the one that smells strongly of fish) where I spent 4 hours straight sorting through tiny, colourless zooplankton… which was so much fun! Basically, we poured the samples into glass casserole dishes so that we could see them better, and then used tiny little forceps to sort them onto Petri dishes. Then we put them in test tubes, labelled them, and preserved them in ethanol.

Coolest zooplankton on the block: Sagitta elegans – a very small, completely transparent arrow worm which is apparently one of the most aggressive predators at the top of the plankton food chain. Never underestimate the small; they may eat you for supper…

Agassiz net : This is the most exciting net of them all. Used for catching benthic invertebrates, it is lowered to the ocean floor and then dragged through the mud for 5 minutes. After being hauled up, we open it from the bottom and catch the ensuing stream of mud, rocks, and creepy crawlies in a big bucket. Then the fun part; sticking your arms elbow-deep in dark, gooey, delicious mud and scooping up anything that wriggles. In our last Agassiz trawl we got a couple of really big crabs and a sweet sucker fish that would suction onto your finger, along with the usual starfish, worms, snails, etc. I personally love mud, it’s a truly delightful substance, and definitely brings out my inner 5-year-old.