17 April, 2023
Current position while writing (basemap from 
ggplot2).
Life on board
Coming on board, it is really difficult to find your way. Everything seems to look the same and, additionally, there are often many ways to reach a place. There are no signs for directions only emergency exit signs. Luckily, the decks have differently coloured floors and doors which is somewhat helpful. On Friday at 8 am we had a safety briefing and afterwards got a tour around the most important places on the ship. That was very helpful, on Thursday, I never really knew where to go.
Impressions from board
All the corridors look similar. At least, the decks have different colours, and each door has a little sign saying what is behind it (even if it is “Corridor”).
There are a few rules one has to know when living on the ship and quite a number of information that experienced people already know. The rules are mostly related to safety: don’t run or jump, always have one hand free to steady yourself or where to wear safety boots. Many other things are mostly experience, like that to flush the toilet you have to push the button quite quickly, wear clean clothes in the canteen, how different parts of the ship are called and so on.
As already mentioned, our departure from Guayaquil was delayed several times. Generally, the planned departure is written on a sign close to the gangway. Beneath it, is the time one has to be back on the ship in order to come along (two hours before departure).
In order for everyone to know what to do in case of an alarm, we had a safety drill in addition to the safety briefing. They started a general alarm (with an announcement beforehand) and everyone had to come with appropriate clothes and a life vest to the muster station. There, it was checked that all were there and then the separation into the two lifeboats was also checked. The Sonne has two lifeboats and eight life rafts. Into each lifeboat the entire crew and all scientists could fit in, however, that would get quite crowded.
Lifeboat. We have two of those and in case of need, all 80 of us can fit into one of them.
Boat to save someone who fell off the ship.
Luckily, the weather has been nice and calm. The ship is only gently rowling and working with that is easy. It is still (very) warm. According to the ship’s measurements, we have around 27 °C air and 28.5 °C water temperature during the day. But at least there is now some wind (2 m/s) that makes the heat bearable.
Sunny and warm
Up to now, I haven’t seen any bigger sea creatures, however, some birds fly around the ship. Some of the others have apparently seen turtles, whales and a seal. My lab is, unfortunately, in the bow. It is quite far away from the other labs and has no windows but I hope that at some point animals will be around when I’m also outside.
Birds around the ship
I missed on Friday evening (because I was already in bed) that we weren’t allowed to go outside because some pirates attacked a container ship. Apparently, Ecuador is a pirate region.
Science
On Thursday, we directly started unpacking the containers, with no introduction into what we are doing or where to find what is on the ship, just bringing boxes from one place to another. And we had a lot of boxes to carry with 30 °C and sunshine. As already mentioned in the first blog entry, each group is bringing their own equipment. With this, they transform empty lab rooms into fully equipped labs just as they need them (if they didn’t forget anything when packing).
Empty lab. This is the way labs look when you arrive. Then boxes of equipment are brought to the lab and everything is set up.
On Friday, we continued to unpack and set up everything. Afterwards, some of the empty boxes were brought back to the containers, so they don’t move around inside the labs at sea. Additionally, we had a science meeting in the evening where the plan for the first measurement station was discussed: when will it probably be, who is doing/needing what and so on.
The first station was planned for Saturday at 6 am, however, it was delayed to 8 am. Everything went well with the first CTD rosette (a tube for deep sea investigations) after everyone had figured out who needs to do what. Unfortunately, at the second CTD, a few things did not want to work, one of the pumps had run dry and needed water and the closing of the Niskin bottles didn’t want to work. So, this CTD was not used at the first station. Maybe you are wondering now why there are two CTDs … One of the CTDs is trace metal clean, it is made from titanium and is used to take samples for measurements of trace metals. The second CTD is made from stainless steel and is used for samples that are not sensitive to trace metal contamination. For the frame, the CTD itself is actually quite a small part, however, often everything (CTD, Niskin bottles, all other sensors) together is just called CTD. I’ll come back to CTDs in a later post.
The next stations went better. However, some of them had quite an “unfriendly” timing, one of them stated at 2.30 am … And it is important to get some sleep in between.
Our two CTDs
„Inside“ the rosette are quite a number of measurement instruments.
By the way, on the first station, I saw a butterfly flitting across the ship. I hope it got back home safely. There still was some land to see on the horizon. At the moment there are still birds flying around the ship most of the time.
Saturday and Sunday, I spent mostly setting up the sensors in my lab. I am taking continuous underway measurements of the surface water. The ship is continuously pumping some seawater in and measuring temperature and salinity, after that I have the water flow into the sink and measure pH, alkalinity, pCO2 (CO2 partial pressure) and nitrate (if everything works …). As in the other labs, I had to set up my lab first and then start the measurements. And while doing that there are, of course, always various problems. Actually, only the sensor for pCO2 did work without problems from the beginning. The nitrate sensor is working well, however, I have to share the cable with the second sensor attached to the CTD. For every station, we are bringing the cable back and forth. By now, we’ve settled into a good rhythm and this works also well.
My lab space before I started setting up. The space is quite loud and has no windows.
Everything unpacked and secured.
For the measurements, I had to rearrange things. Eric (my doctor father) built me a cover for the sink on Sunday to reduce CO2exchange with the air.
It was planned that I measure pH with two different sensors. However, one of them does not want to get a connection to the laptop at all. By now, we’ve tried everything that’s easily doable in the lab and asked a couple of people who have experience with the sensor. The general consensus is that the cable is faulty. So, when all bigger problems are solved, the ship’s electrician will have a look at the cable. The other pH sensor also made problems in the beginning, luckily they were easy to fix with a new sensor cap.
The troublemaker. This pH sensor doesn’t want to communicate with the computer.
The instrument to measure alkalinity underway is the most complex I have to set up. It isn’t as far as the others in its development (the others are commercially available). So, on Sunday, I started following my list of things I need to do to make it run. This took a while but it seems like it is running now.
Everything is secured. The big, white box in front of the sink measures alkalinity. The containers behind it have reagents it needs for the measurements.
Apart from the troublemaker, everything is set up and is measuring. This is quite nice as I get more rest, especially together with the fact that our stations are in the daytime at the moment (but being at station at night is also nice, we can watch birds and fish in the ship’s lights). The last few days, have been so busy that it is hard to keep a feeling for time and what happened on which day.
PTB doctoral student 
Rieke Schäfer is blogging here directly from the RV "Sonne" on her way west from South America across the Pacific Ocean.