Once again, I am onboard RV Sonne, together with some very fascinating people. Let's take a look at who is here and why!
RV Sonne
I am on a research cruise across the South Indian Ocean. It is my second time onboard RV Sonne, Germany’s one of the newest and largests research ships, and I am here with many other researchers and students across Germany and the world. A good portion of them are PhD students. I talked to them (plus one postdoc) to see what they are doing. Let’s take a look at why they are here!
Tobias
Who are you and what are you doing?
I am a PhD student in GEOMAR, Helmholtz Center for Ocean Research in Kiel. My main field of research is Marine Biogeochemistry, although I also work with Marine Ecology. I did my BSc and MSc in Kiel too.
My project is funded by the EU as a part of a greater study dealing with every type of the carbon in the ocean. For the first part, I investigate the vertical particle fluxes and the influence of the environment. I do this by in situ optical imaging. The vertical carbon flux is basically what we call the biological carbon pump, or the mechanism that allows carbon to sink and be stored at the bottom of the ocean. The dissolution of the organic particles by microorganisms and zooplankton plays an essential role, and how much carbon can be taken up is a very important question that we need to answer for climate change predictions. The second part is the marine ecology part, where I look for the biodiversity and abundance within the plankton.
My goal for this cruise to collect data for the 3rd paper I will publish within my PhD, about the second part of the project. There is not a lot of data collected in this topic from the Southern Indian Ocean, especially optical data. Not many people have been here as it is far away from many industrialized countries. I am looking at how the biodiversity changes along the transect. There are some species that are not thoroughly studied yet. So it is interesting to see what we observe here.
I am responsible from the cameras. We have the PISCO system, which is the larger camera, and the UVP. Both are plankton/particle imaging devices. I manage the devices, collect data, and process the data. We deploy them with the CTD rosette (the water sampler we use). I also do some filtration work for some colleagues who are back on land.
How is your experience so far?
This is my second long cruise. First one was to the Arctic Ocean with , so this cruise is very different in terms of both the outside views and the inside of the ship. I prefer the working areas and the food on RV Sonne. It is a nice ship to work on and I am really enjoying it. Apart from the very tough schedule of course. We had some extremely busy days with very little sleep, but it is going to get better. I also appreciate the single person cabins. It makes living onboard much more comfortable.
Catia
Who are you and what are you doing?
I’m coming from Brazil, where I did my bachelor’s and master’s degrees. Then in 2018 I got my scholarship from DAAD to start my PhD in Germany at the Greifswald University/Leibniz Institute for Baltic Sea Research Warnemünde. It started very nice as we had a meeting with the DAAD scholars from South America to learn more about Germany. Throughout my PhD I was also very well supported. I finished my PhD in 2023, and as I really enjoyed my time in Germany during my PhD, I decided to stay for a postdoc at the same institute. Now I am on my second postdoc at another institute in Germany, Leibniz Centre for Tropical Marine Research.
I work with processes at the land-ocean interface and what is very interesting is that my PhD was focused in the Baltic Sea, and I used to work in cold environments and now I have moved to the tropical research. It’s a completely different world. I’m working a lot in different countries, which is very interesting.
Within this land-ocean interface I’m focused especially in geochemical processes, and a very useful tracer is the element radium (Ra). Ra is radioactive and has different half-lives, and depending on the half-live it can be used to identify different processes. Higher activities of short-lived Ra isotopes, which have a half-live of three days can indicate, for example, strong porewater exchange. Higher activities of long-lived Ra isotopes could be, for example, an influence of a different water mass. And that is what I’m doing on this cruise. I’m collecting samples for Ra isotopes along the transect. They will help to identify and quantify chemical elements fluxes from the continental margins into the open ocean, and to understand the movement of water masses and how this affects the transport of chemical elements.
How is your experience so far?
I really like being out in the sea. I choose to work with the marine science because I like to be close to the coast and also work with the ocean. Being in this very advanced research vessel where we can have different research going on is super nice. And I’m learning a lot, not only my own work, which is a challenge every day, but also what other people are doing. I think I’m really, really enjoying being here.
Polina
Who are you and what are you doing?
I’m Polina, originally from Russia, currently doing my PhD in Geochemistry at Constructor University in Bremen, Germany. My research focuses on the distribution of high field strength elements (HFSE) in the ocean water. HFSE are a group of metals, characterized by small ionic radii and high charges, making them highly particle-reactive. Their distribution and geochemical behavior in ocean are not well studied and described yet, so I plan to analyze them and then describe what geochemical role they may have and in which processes they are involved. The first two years of my PhD were spent with method development because we didn’t have a method to analyse these elements in our lab, and I needed to develop the method myself. Now, I started getting the first good results from the method I developed. It will give me the opportunity to analyze my samples. So far it is working with high accuracy, especially with elements like Zr, Hf, Nb.
Onboard, I’m taking samples for our group for trace metal geochemistry research, so not only of my own work but for my colleagues‘ as well. The analysis and samples treatment are too complex and can’t be done in the ocean, so we need to carefully prepare these samples for storage and transportation to be analyzed in the lab. Together with my colleagues we perform filtration onboard, to study element distributions in different fractions. It takes a lot of time and is necessary to do right after sampling. Then, depending on the parameter, we either acidify or freeze the samples to preserve the elements in a stable, analyzable state. Everything has to be done in trace metal clean environment, to guarantee the best quality of the samples.
How is your experience so far?
I like being here! It’s absolutely a different rhythm of life. Our sleeping schedule vary with shifts. It’s not like there is a day time and there is a night time: everything is mixed together, because sometimes we have to work at night or early in the morning, and sometimes during the day. Work can be quite exhausting, but it’s really beautiful to be in the in the ocean. I like seeing the horizon and this endless ocean, and how colors change. It’s also a quite unique experience to share a limited amount of space with many different people. It’s exciting to share this journey and find something special every day, making the cruise truly memorable.
Aleks
Who are you and what are you doing?
My name is Aleks and I originally come from Latvia. Now I’m a PhD student at the University of Rostock and I was sent to this expedition with a single particle mass spectrometer. Here I am trying to get some good data for my first paper. It’s about aerosols, the little tiny particles in the air that fly around and are potentially dangerous to human health and to the environment. I am mostly interested in aerosols from the big ships that are using heavy fuel oil. I’m trying to see the elemental composition of aerosols and get an estimation of their amount. The aerosols are collected and analysed by blasting them with two lasers, and trying to gather the remains. In more scientific terms, single particle ionization of aerosols.
How is your experience so far?
It’s actually quite fine. I got used to being on the ship pretty quickly. The seasickness was the worst part in the beginning but it got less over time. It’s also a bit difficult to work when your whole lab is rocking, and the instrument is trowing errors that had never occurred on land. The best part about this cruise are the people, the food, and the view. I was pleasantly surprised by how much help I got on board. I was also not expecting to get to know so many absolutely wonderful and interesting people.
Martin
Who are you and what are you doing?
I am Martin, from Bavaria in Germany. I studied the Earth Sciences in Munich, and got my Bachelor’s degree from Ludwig-Maximilians-University and Technical University Munich. Then I continued pursuing my Master’s degree also in the Earth Sciences at ETH Zurich, Switzerland. I started my PhD there as well. I am working on water column geochemistry.
I investigate the relationship between the carbon (C) and nitrogen (N) cycles, and how microscopic marine algae, called phytoplankton, play a role here. Phytoplankton are extremely important as they take up CO2 from the atmosphere to build their biomass, which is partially sequestered on the ocean floor. Apart from major nutrients such as nitrogen (N), phytoplankton growth depends on the availability of trace metals such as iron (Fe) and nickel (Ni). However, these micronutrients are often depleted in the surface ocean, hence limiting phytoplankton growth. This is where my PhD project starts: I am investigating how different chemical species of Ni affect phytoplankton productivity in certain ocean regions which are limited by both N and Ni.
I am participating on this cruise for multiple reasons. First, I am collecting water samples from different locations along the cruise transect to extent the dataset of Ni abundance in the Southern Indian Ocean. Unlike the Atlantic or Pacific, very little data is available from this region, not only for Ni, but also for other elements and nutrients. Second, I am performing several experiments in different labs onboard, including nutrient additions to see how phytoplankton growth is affected by different nutrient regimes. As this requires large volumes of seawater, these experiments can only be performed while at sea. Seawater samples are spiked with nutrients inside a special trace metal-clean environment, which is a plastic „tent“ called the „bubble”. Additionally, I am extracting dissolved organic matter (DOM) from seawater to measure the concentrations and isotope compositions of the adsorbed Ni fraction once back in the home laboratory.
How is your experience so far?
It is a great experience and privilege. Even though science and everyday life are sometimes challenging, the great views, including sunsets, sunrises, and the vastness of the ocean, are absolutely rewarding.