Station 1!

Today was our first day of sampling! Kristine woke up at midnight, 1 O’clock, and 2’Oclock in the morning to take samples of nutrient concentrations, phytoplankton for identification, photosynthetic pigment analysis, and measurements of organic nitrogen and carbon levels. These were taken for our underway sampling (when we are steaming from station to station). Andrew got up before sunries to take a net sample and see what phytoplankton were in the water. Today’s station was near the edge of the Amazon River plume with a salinity of about 31. Andrew found mostly Trichodesmium, with a few diatom-diazatroph associations. There was also some sargassum in the water.

Some of our fellow scientists took sediment core samples early in the morning to look at natural isotopes, after which there were 3 casts of the CTD Rossette to sample for many different parameters. Various labs examine pCO₂ levels, marine microbes, nutrients, seawater optics, genetic diversity and gene expression, and all kinds of organisms from marine viruses to zooplankton.  During the third cast of the CTD (at 11am), Andrew took samples to measure the primary productivity and carbon excretion of phytoplankton and Kristine assisted by taking samples for chlorophyll A , DOC (dissolved organic carbon), and phytoplankton identification. Andrew is incubating his samples for 24 hours in one of the awesome incubators on the deck (look forward to pictures from future incubations!), and will be able to find out how cells behaved tomorrow by measuring their uptake of radioactive carbon (¹⁴C) in his “Rad Van”. Rachel took samples to quantify and identify phytoplankton, taking special samples for Trichodesmium  (colonies of nitrogen-fixing cyanobacteria) and very small single-celled cyanobacteria such as Synechococcus and Prochlorococcus.

Later, some labs took samples of zooplankton using the MOCNESS (Multiple Opening/Closing Net and Environmental Sensing System…yes, I had to google that). We were going to try to do another two CTD casts to take deep water samples this afternoon, but weren’t able to because of some CTD communicatioin errors. Because of this we are taking off from this station a little later than expected. Tomorrow we will have a similar schedule to the one we had today, but may see some differences in phytoplankton abundance and distribution since we are moving closer to the plume center.

Life on the boat is great! None of us have gotten seasick yet, and the food is wonderful. The chefs are very thoughtful and put aside plates of food for us when we have to work through a meal, and the crew is very friendly. Kristine and Rachel are sharing a room on the bottom level of the boat, and Andrew is one level up. We will keep you posted on our future sampling and experiments!

-Rachel