Svenja burst into the red lounge, where a group of scientists were having a post-prandial chat. The alien announcement was irresistible, and we trooped down to the lab where Svenja’s fresh multinet haul was awaiting earthly attention.
Under the microscope we saw live zooplankton hopping, spiralling, leapfrogging and swimming through the sample. Then, carefully teased free from detrital clumps, a ghost-like carapace of an amphipod floated into view. “This is the species that inspired the movie ‘Alien’, look at it’s eyes!” Svenja enthused – a blockbuster discovery! Scientifically speaking, she had caught a “Phronima”, a parasitic amphipod that lays its eggs into the barrels of salps and pyrosomes.
We are in the North Atlantic on RV POLARSTERN, our home and floating University for the WASCAL Marine Science Programme for two weeks. Svenja Christiansen, lead instructor for the zooplankton investigations, had her students prepare the multinet to pull up samples from 800 m in five depth intervals. Day and night, literally. What sounds like uninterrupted work is actually the way to follow diel vertical migration, whereby zooplankton wander upward to surface layers at night and descend to darker depths during daytime.
WASCAL student Traore Sienfoungo from Ivory Coast will be using the samples for her Masters thesis on zooplankton distribution and composition, and their changes in different water masses. “A previous study was done in 2015, and I want to compare my results to this, to see if there have been changes, perhaps associated with warming trends” she says. What has the experience on board meant to her? “It’s crazy amazing to see the zooplankton alive in a fresh sample”, her eyes sparkle with joy “and I know now that I could go out the next time and collect them myself”. It certainly beats working on samples stored in a lab cupboard!
Despite all the exciting net samples, Svenja thinks that deep-sea ecologist like her are still largely in the dark as to the inhabitants of the vast ocean depths. More “alien” discoveries to be made!
Yet another day on the RV POLARSTERN, our floating University.