By Rita Melo Franco Santos | Polarstern is currently located in the vicinity of the 79^oN Glacier, an area of high scientific interest especially for the geologists and physical oceanographers, as the region holds answers to many unanswered questions our researchers have in mind about the geological history of the site and the circulation of warmer water masses coming all the way from the North Atlantic. This is a region where very little work has been performed due to the difficult access because of the constant thick and abundant sea ice. PS100 was a lucky cruise though, and the good weather allowed for our navigation through these unchartered waters to investigate all sorts of processes occurring at the mouth of the glacier. The biology team, which I am a part of, has also had the opportunity to sample in these waters, finding a very interesting zooplankton composition and abundance that can further help understand physical oceanography processes in the region. It is all hard work with long and odd working hours, but very exciting for us and well worth everyone’s effort!

As part of the biological team onboard under the frame of the AMICA (Arctic Marginal Ice Zone Community Assessment) project, we had our most intensive sampling period during the third and fourth weeks of the cruise, as Natalie Prinz already mentioned in her blog post. My very own PhD project, or part of it, was included within the frame of AMICA. During the cruise I have been working on the adaptive capacity of calanoid copepods, crustaceans which are very abundant worldwide and which make up a significant portion of the zooplankton in the Arctic. In order to do so, I perform two types of experiments, both related to the type of food given to the copepods but each with its own goals.

The first one is related to how the copepods process and absorb different types of food, during which I investigate the changes in composition and relative abundance of fatty acids in relation to the different diets provided to copepods. For the second experiment I try to understand how is food utilized by the copepods, and this is accomplished by estimating certain vital rates, such as respiration, consumption and production of faecal pellets. The main idea is that everything that a copepod eats must be used either for growth, be it an increase in weight/length or for reproductive purposes (i.e., producing eggs), or be discarded as waste, such as respiration, excretion and faeces. Such vital rates can then be analyzed in the context of different foods given to the copepods, possibly indicating whether the crustaceans would be able to survive on different foods than what they currently feed on in the wild.

In order to obtain my samples we have been using a type of sampling gear called Bongo net. This net was lowered down to 50m depth, where my target copepods are very abundant, and hoisted up vertically to the surface, collecting all of the zooplankton on the way. The catch was then sorted in a cooled container and I was ready to start my laboratory experiments! I have been able to perform four experiments, and as time is closing in on us and we will soon have to pack up all of our equipment for the end of the cruise. It is a mixed feeling of mission accomplished and of end of cruise blues as I dip my full arms in a bucket with shampoo water to thoroughly clean the nets from another sampling gear, the Multinet. The very last contact we will have with animals coming straight from the ocean is happening in 45 minutes, as our last Bongo net sampling takes place – the approaching end of my Arctic adventure.

I have been so fortunate and privileged to be able to join in on the PS100 cruise. As early as during my B.Sc. in Oceanography I have dreamt of conducting research onboard Polarstern, the great German ice breaker. When applying for my current PhD project back in late 2013 I knew of the possibility of joining the cruise as a part of the project, and that mix of hope and excitement has populated my heart ever since.

It was only as I stepped onboard the ship on July 18th 2016 that I finally believed my dream was coming true. We have been very lucky to have great weather during the cruise and days and nights that seemed to be the most beautiful ever, only to be succeeded by even more spectacular days and nights. Working at any time of the day can be hard, but it also allowed me to experience the Arctic environment at all times of the day, and with the 24h daylight of the summer in the region, that meant beautiful colors in the sky and many magical moments.

As I started this adventure, I only had expectations about life onboard the ship and the research to be conducted – I guess I forgot about dreaming of the associated experience. As a tropical species myself (I come from Brazil), I would have never expected to feel what I have felt in the past weeks – I have fallen deeply in love with the Arctic and all that is related, the ice, the polar bears, the fog, the wind, the birds. The ice that warms my heart and calms my soul. It has been a grand journey of learning and of experiencing, and I can only hope it is the first of many to come. As the days in my calendar approach September 6th and the sadness of leaving the ice sets in, I am left with wonderful memories of the people that I have met onboard and of the sights I have seen, but also with the exciting thought and expectation for the arrival of my samples back in Bremerhaven when the ship returns to port in October, so I can finally obtain answers to the questions that brought me to the land of icy dreams in the first place.

Rita Melo Franco Santos