Studying Caribbean eddies
Climate Physics student Anneke Vries joined the NICO expedition organized by NIOZ Sea Research and NWO
In his Ted Talk , Paul Snelgrove states that we know more about the surface of the moon than about the (deep) ocean. Before joining the NICO (Netherlands Initiative Changing Oceans) expedition, I never really thought about how ocean data were collected. Of course, stories of famous oceanographers who sailed around the globe and occasionally got stuck in the sea ice come to mind. However, I figured it wouldn鈥檛 be the same these days. During the week-long NICO expedition I could find out for myself, because the Royal Netherlands Institute for Sea Research (NIOZ) offered master students the possibility to experience a research cruise to get them enthusiastic about sea research. In return, I had to help take samples and support scientists where needed. This NICO cruise is special since so many different researchers are involved. Participants in my leg were physical oceanographers and biologists studying birds, flying fish and sea mammals and trying to record whale sounds. Whereas in normal scientific life people stay within their own scientific bubble, being on a boat literally forces scientists to step out of their comfort zone and enter uncharted waters.
The NICO research cruise left in December 2017 to cross to Atlantic Ocean to the Caribbean and return via Ireland. I joined Leg 4, sailing across the Caribbean Sea from Aruba to Sint-Maarten. There were 24 people on the ship, of which half kept the boat sailing. One of the goals was to study the big whirls or eddies that pass this region every once in a while, and travel westward to the Gulf of Mexico. This was pretty exciting, since we only had a limited time frame to sail from one island to the next and we didn鈥檛 know whether we were going to be lucky and would catch an eddy. Once at sea we stopped every few hours to take a CTD measurement: lowering a metal frame with all kinds of sensors and sampling bottles to a depth of 2 km (or the sea floor) and then waiting to retrieve it. A week at sea with work that continued 24/7 allowed us to get over a dozen profiles. Despite some technical problems and a pretty slow boat (only one generator set worked), we were lucky to almost cut through the middle of an eddy.
Some physics researchers don鈥檛 see what they study because it is too small or too far. Studying the physics of the ocean is different because you see all the water, but it is actually too big and too slow to see the movements. For instance, being inside an eddy means that the water moves around you and that you might actually be half a meter higher or lower than the edge a few hundred kilometers away, but being on a ship you won鈥檛 notice this. The cruise helped me realize how big the ocean is and how hard it still is to get good measurements. Apart from it being a fun experience, this week at sea showed me how much is still left to be discovered.
Anneke Vries
Master Student Climate Physics