30th May : A week on board the James Clark Ross: Megacorer and Co

Last Sunday our mission began…

It all started a week ago very early in the morning. A taxi, two flights and another taxi journey later Nina and I arrived at the James Clark Ross, which was moored in the harbour of Vigo.  After boarding we had some hard time finding our way around the ship without getting lost. But some hours later we found all our boxes, the megacorer and knew how to get to our cabin. As this is my first cruise, I was really excited and wanted to sail as soon as possible, but it turned out that we all had to be a little more patient than expected. The James Clark Ross finally set sail at midnight on Wednesday, steamed full power to the Porcupine Abyssal Plain and everybody started to get busy. The main purpose of this cruise is to deploy a mooring with all kinds of different of sensors that transfers the gathered data over satellite to shore.

But lots of other things were taking place:

The CTD and the algae incubation chambers were prepared, sensors for the buoy and the mooring were set up, pelagic traps thrown over board, a kite competition called out and we concentrated on the deployment of the megacorer!

Deployment of the megacorer

To make everything a bit more exciting we have a film team from National Geographic on board. They filmed most of our work and attached their drop camera to all sorts of equipment.

But back to the megacorer! It is a pretty heavy device that takes sediment cores down at the incredibly deep bottom of the deep sea (around 5000m). From the deployment over the side of the ship until the corer reaches the Porcupine Abyssal Plain of the Atlantic it takes about two hours. Down there the megacorer comes to live and its cores are pushed into the mud. As soon as the corer is pulled up towards the surface again special shutters close the open end of each individual tube. Another two hours later the device is brought up on deck and everyone is waiting for the first glimpse of the cores that reveals how successful the deployment has been.

Thanos Gkritalis and engineers prepare the meagcorer for deployment

For me it was stunning to see how deep-sea sediment looks like. Somehow, I was expecting a dark brown mud, but it didn’t look anything like that. It came out to be light clayish and very fine sediment.

Nina Rothe gapples with a sedmiment core fresh from the deep sea (4800 m depth)

To keep the organisms as conserved as possible we transferred the samples to a 4˚C lab where we sliced different sections of mud to investigate the changes in communities within the different layer of the sediment. Because the samples we are taking are part of a time series, not only the different organisms in the layers also the changes over time can be estimated. All the organisms will be analysed and identified in the lab back in Southampton.

For now, I am sitting and waiting for the corer to come out of the water again so the mud game can start again.

Hanna Shuster

Nina Rothe (left) and Hanna Schuster (right)

Nina Rothe and Hanna Schuster on sampling table

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