Ocean science from a life scientist’s point of view – the M133 SACROSS cruise

© Christine Falk

Before I had the chance to participate in the M133 SACROSS cruise, the ocean, in particular, the Atlantic Ocean, was already fascinating, beautiful and somewhat mysterious. Despite lectures, movies, animations, etc. regarding several aspects of physical, chemical and biological oceanography, I could not quite imagine how experiments of measuring the ocean on a research vessel would really work. So, obviously, this adventure of crossing the South Atlantic on Meteor would be much more than a scientific experience “in the middle of nowhere”.  But I never expected that it would be such a unique mixture of “big” experiments (from a life scientist’s perspective), excellent lectures, great fun and cuisine at Christmas and New Year’s celebrations, endless variations of ocean and sky from blue, red, orange, green to gray (Fig. 1), and most importantly, the team work with the best watch ever :), the LASY shift (LAte, Smart & Young) with Lea, Iole, Elisabeth and the crew, Derk (ja, die Brücke), Olaf & Alex – true masters of the winch. Together, we learned quite a lot from Andreas, THE technical expert on board, how to handle CTD (conductivity, temperature & density), uCTD (underway CTD), XBT (temperature) measurements – and, how to solve all kinds of problems whenever they may occur in this 24/7 routine of collecting data of the ocean (Fig. 2). The entire Meteor crew, including captain Rainer, is more than wonderful and for sure, has a lot of experience with “funny” scientists who need a lot of hands-on training and support :).

The dimensions in life science versus physical oceanography couldn’t be more different: while in my lab in Hannover, I am used to work with milliliters of blood analyzing hundreds of parameters, here, we are dealing with hundreds of liters of water, collected up to 2000 m deep in the ocean and measure the most important physical parameters, i.e. temperature, salinity, oxygen, alkalinity and several others. My view of the ocean as “one water world” has changed completely during this cruise because I learned with our own measurements and profiles that there are layers of water masses with defined temperature, salinity & oxygen, carbon etc. content. These water masses remain quite constant, still mysteriously to me, over thousands of nautical miles and may come from Antarctica or North Atlantic, for example, without extensive mixing. The transformation and mathematical modelling of the data is also fascinating to me and I’m still thinking we may even be able to use some of these techniques for our big data analyses in life science.

© Christine Falk

The connection between life and ocean science came via an elegant technique, the FlowSight technology, a combination of flow cytometry and microscopy that can also be used for the measurement of both blood cells and – phytoplankton. So, the idea is to test on M133 different fixation techniques with phytoplankton taken in MultiNet or CTD experiments for later measurements with the Flow Sight system. It would be too amazing if this could work not only with harbor-derived material but also with plankton samples from rather remote places like the South Atlantic.

The “foram” group from Marum, Bremen, adds another fascinating element to the oceanography in board with paleogeology. The group is collecting foraminifera, single cell organisms with beautiful shells that exist since hundreds of thousands of years on earth and build a large proportion of the oceanic sediment. Therefore, they can be used as “proxy” for modelling of the climate in geological scales of millions of years. Since I never had a clue how evolutionary successful and geologically important forams could be, I’m really impressed! Moreover, the MultiNet of the foram group turned out to be an elegant alternative for collecting zoo- and phytoplankton for my fixation experiments – thank you so much for your great help, guys! In addition, it’s also great fun to work together in art projects like the Christmas play and our New Year’s choir.

This is just a glimpse of the experience here on the M133 SACROSS cruise that I’ll certainly never ever forget!



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