Hello again from the Geomar-Coring Team, or as we like to call ourselves, the Mud Team. We have good news: The sampling went well, and we collected many sediments in the first fjords! Now, we are on our way to the third fjord, and as we get slowly used to the waves, we want to use the time to give you a small insight into what happened last week.
To get the mud, we so eagerly want to sample, from sometimes 800 m depth, we are using a Mini MUC. MUC stands for Multi Coring, and our is a Mini MUC because it can collect 4 sediment cores at one time. Regular MUCs can collect much more. We named our MUC Nemo the MUC or just Nemomuc. To prepare him we secure 4 plexiglass cores and load 4 springs, which are holding the lids for the cores. Once Nemomuc reaches the ocean floor, the cores sink into the sediment, and the springs are released to seal the cores so no sediment gets lost on the way up. As the full MUC arrives back on deck, the mud-team is filled with happiness and can not wait for the next steps to happen.
To sample the sediment, we are cutting layer by layer of the sediment core to collect each layer individually. Once we return the samples to the lab at Geomar, they will be analyzed for DNA, RNA, iron bioavailability, porosity, and much more. Due to our interest in iron and the property of iron to react with oxygen, we need to do our sampling in an oxygen-free zone. A glove bag filled with nitrogen to flush out the oxygen is used for this instance. This means that for most of our work, we sit in front of a big plastic bag and have our hands in two gloves that are on the inside. This is a practical way to create this oxygen-free zone, as it is easily set up on a ship where you don’t have the equipment you normally have in a lab. To avoid the sediment becoming warm and the conditions not being representative of the ocean floor anymore, we are working in a container on the ship´s deck, leaving the door wide open so it doesn’t become too warm. This means no heated lab for us inside the ship, but we have at least the lab with the best view. We are quite happy with our samples, and working in this improvised lab with our plastic bag is going very well. The only bad surprise we have so far is the presence of mosquitos. Who could have ever thought that there are so many mosquitos inside a Greenland fjord?! So, while one of us is working on the sediment cores, the hands are occupied inside the glove bag, defenseless against the giant mosquitos. The other person usually labels sample tubes for the next cores but now has the new task of fighting the mosquitos while the other person can’t.
This is it from us so far, but you will surely read from us again.
The Mud-Team, Carmen and Malte