As with many other elements of the polar night environment, the microbial food web is an unknown system that has been receiving increasing attention in the past few years. What was previously thought to be a dark period generally void of biological activity, studies from mare incognitum members and others have recently proved otherwise for several organisms. Although the bacterial and microplankton abundances are definitely much (!) lower than in the spring bloom, there is a persistent stock of these small organisms and some evidence of growth during the dark period.
One of the master students on board, Martí Amargant Arumí, is trying to get an overview of how many of these small organisms are present, how active they are, and how much they are being grazed upon. For this, he takes daily water samples from different depths and prepares them for analysis with flow cytometry and epifluorescence microscopy, and in parallel conducts serial dilution experiments. Serial dilution experiments alter the rate at which predator and prey meet: the more diluted a water sample is, the lower the overall predation effect over bacteria is, and the more freely they are allowed to grow. These experiments provide us with an insight on bacteria growth rates and the grazing rates to which they are subjected to in the wild. All of these procedures must be performed strictly in the dark, which is the reason why he can always be seen with a headlight on and unable to locate his tools in the lab.
-Martí Amargant Arumí (Master’s student, UiT)