After finishing up our transect at 60 °S, we headed east. We’ve spent the past two weeks or so chasing interesting oceanographic features like eddies to see what they can teach us about phytoplankton in these waters. Eddies are sort of like the weather systems of the ocean — big swirls of water that move through the water. They’re much bigger than atmospheric storms but less ferocious (I’d imagine sailing through an eddy is much less stressful, than flying through a hurricane), and as a result, they can hold their shape in the ocean for several weeks at a time. This makes them really interesting features for us to study — they can sort of ‘trap’ water and allow us to study how the water changes over time by returning to the same feature.
While following these features has been our plan all along, it worked out even better than anyone could have hoped for. We spent last weekend steaming northward through a gargantuan bloom of coccolithophores. But when we passed through almost this exact spot in January, there was very little sign of the coccolithophores we have been hunting. On our return trip, the ocean has been positively teeming with them — they’re so abundant that the water outside even looks sort of milky (at least, to Barney Balch’s well-trained eye!).
The emergence of this coccolithophore bloom offers up a really exciting and unique scientific opportunity for us to look at the water conditions both before and during the bloom. By comparing the two timeframes, we hope to get a better understanding of what makes coccolithophores happy in these waters.
This Monday marked the last day of ‘over-the-side’ science operations — the last time we put the CTD or the trace-metal-clean bottles into the water. Although we’ll have a few more days of taking samples from our underway system, which pumps water directly from the ocean into our sink, the bulk of our shipboard work is done. We marked the end of science on Wednesday with a ceremonial cutting of the CTD cable — everyone joked that this was to prevent Barney from trying to squeeze one last one in somewhere along the trip back.
We also had a separate celebration immediately following the last CTD cast on Monday. Melissa, one of the Scripps chemists on board, is starting a new (non-ship-based) job when we get back to land, so to celebrate her last-ever cast, we dumped some buckets of 44 °F water on her from the rosette. The joke was on me though, because she grabbed me in a big bear hug and I also got soaked!
We were initially supposed to have another week’s worth of science, but earlier this month, the French government decided to close its borders — including those of Tahiti, part of French Polynesia. Instead, we’re heading back to Honolulu, which is a much further ride from the Southern Ocean. We always knew this was a possibility, but it was still a bummer to lose out on so much potential science time. At the same time, we’ve been incredibly lucky with the weather this whole trip, and everyone is very excited about all of the science we were able to do.
Meanwhile, almost overnight, it feels like we left the Southern Ocean and hit the tropics. By the time we reached 40 °S, it was over 70 °F and sunny with beautiful blue skies. It’s a good thing we’re done with science because all anyone feels like doing now is sitting outside and enjoying the good weather. Over the next two weeks, we’ll have to pack our samples, tidy our lab spaces, and put together a report that documents everything that happened over the course of the cruise and all of the science that we’ve accomplished. But for now — time to sit back, relax, and enjoy the sun!
Giuliana Viglione is a journalist and science communicator who has joined Senior Research Scientist Barney Balch’s research cruise to study the impact of coccolithophores in the Southern Ocean. On board the ship, she’ll be helping the team carry out experiments, document the research cruise, and conduct educational outreach with students across the country. She can be reached at giuliana.at.sea@gmail.com.