Keep drinking!

Here we are, in the middle of nowhere, doing holes in the seafloor and collecting liters of seawater.

Being in the middle of nowhere means that if you realize that something is missing, you can't go out and buy it. But we are scientists, and we've already planned all the work before boarding. Sure, but if there is no way to use a filtration pump, that means no way to empty the bottles from the previous sampling, than you should start thinking about alternatives. You really want to collect more seawater, from all the different stations, since you really believe it could contain the answer for lots of scientific questions.

Right containers to collect seawater

What to do? Improvise.

And that's the moment in which all the crew is there, ready to help you. "Please, I need ALL the empty plastic bottles to collect seawater, don't throw them away but give them to me! Keep drinking! "
In less than 8 hours, 30 bottles are there, ready to be filled.
(It's turned also out to be a recycling campaign). Thank you to all the crew!

Keep drinking!

 There still are some days remaining to find a solution, but at least the water is there, stored at 4°C, waiting to be processed (I don't want to think about the hard work to bring them back to Aarhus...).

Emergency containers: bottles of water

Having fun onboard

When we are not working (intensively…) on the sampling program, there is time for some fun in the hobby room at Dana. Despite of the waves, Julie and Diego managed to play dart while Cristina and Christof had some fun with the cross trainer. Later they put out the ping-pong table and they had some laughs about that.

Written by Melanie Sønderup

Box core

One of the many things we want to study is the oxygen profile in the very top sediment. For this we use a “box core”, or as the crew has named it “Brutalis” (see picture below), as it is quite dangerous at big swells, as it swings heavily to the side of the ship.

So far we have tried to take box cores 3 times without any luck. The sediment is so hard that “Brutalis” cannot close around it, and therefore the core tilts inside (picture below). A perfect sample would be horizontal and having water on top.

Written by Melanie Sønderup

Some of our activities on the 27th April

In short, yesterday, we finished the description of the first gravity core (last sections), retrieved a short gravity core full of benthic foraminifera, opened it and described this new brownish sediment core.
We also learned how to do crazy knots with Kim :)
In the evening, we collected water from the CTD for Suzanne's colleague, Marta and Fatima. We also try to catch European eel's larva... and found all sorts of different small organisms except the precious ones.... :(

On the left, Kim our knot teacher, with Melanie, Maria, Peter and Anna-Marie. On the right, Christof and Diego opening a new core section. On the bottom, a section of the core full of foram (concentrated especially in the lighter part).

Small squid, jellyfishes, and crustaceans, Fatima in orange protective gear ready for the net retrieval, Cristina helping Marta and Fatima with the CTD water collection. 

Gravity core sub-sampling

As mentioned earlier by Marion, the core sub-sampling was divided into two different procedures : pore water sampling and solid phase (sediment) sampling. It took us the whole day on friday to sample the entire 6m core, and despite a few minor difficulties, the operation was a success!

Pore water sampling

Pore water was collected with rhizons that act a bit like the root of a plant by sucking up water, while the other end is connected to a tube that has been vacuumed. Pore water was sampled every 25cm for the 5 first segments of the core, and then every 10 cm for the upper-most segment, for a total of 30 samples.

Two rhizons connected to exetainers for pore water sampling

We started with the bottom segment of the core and the sediment was so compact that the rhizons would not penetrate! We then had to drill holes through the core to be able to insert the rhizons and everything went well eventually. The pore water was distributed to smaller tubes of different colors, each type corresponding to a specific analysis. The tubes were finally stored at appropriate temperature depending on the analysis to be performed (4°C or -20°C).

Sediment sampling (solid phase)

Small windows of approximately 3-4 cm of width and half-diameter long were cut into the core’s tube to prevail the sediment from being disturbed too much and to minimise the exposure to the surrounding environment. With the use of cut-syringes we sampled specific volumes of sediment – 2mL or 5mL depending on the analysis.

Sampling syringes for the solid phase

Sediment being sampled for solid phase analysis

To stop the methane production by bateria we transfered the sediment into vials containing a saturated solution of NaCl. The sediment sampled for cell analysis was transfered into falcon tubes containing PFA (paraformaldehyde) and a 35 g/L NaCl solution.

Slicing the cores

Today the geologists could start their work on the successfully taken gravity core. On the photos Cristina, Fatima and Christof are slicing the uppermost section in 1 cm slices. Melanie and Peter are labeling zipper bags in which the sediment is stored. They are also taking notes about conspicuous changes or details in the sediments. The geologist found for example volcanic stones, shells of pteropods and molluscs.

Written by Anna-Marie Klamt

The "banana" corer

A gravity corer is not supposed to look like this...

At our second station, the gravity corer encountered a hard layer in the sediments, which severely damaged our equipment. Luckily we have enough spare parts to get it fixed in time before our next planned deployment.

The only solution was to cut through the steel pipe

Despite the trouble we still managed to extract more than 4 meters of sediments!