David Needham

One of our goals today was to find and sample a large phytoplankton bloom to study phytoplankton and bacterial associations. Although blooms often occur in the spring, they can be hard to predict, and the ocean doesn’t give its secrets away easily! Fortunately, we identified a large bloom using observations from satellite chlorophyll sensors in space and measurements of fluorescence taken with the ship. The bloom covered a large region of the ocean and was about 50 times the typical chlorophyll values for the region and about 10 times the current levels of the surrounding waters (in the bloom the chlorophyll level was 20 micrograms per liter). Charmaine Yung, our co-chief scientist, will assess the phytoplankton and bacteria in the samples collected in the bloom. She is in the process of trying to culture them as well.

Today we had a second successful dive with the ROV Doc Ricketts. On this dive to 3,600 meters, we retrieved the seafloor incubation experiments set out by Maria Hamilton the day before, and collected 20-centimeter-long sediment cores for Rachel Harbeitner Clark’s research. With many cores coming on board at once, many members of the science team pitched in to help process these cores, getting muddy in the process. Each core was photographed, and then samples were taken for microbiology and geochemistry analyses. Researchers will identify the active microbial communities within the cores (via the microbes’ DNA) and determine the substrates that fuel their growth. While the microbes’ primary source of energy is exported from the surface ocean over three kilometers away, thankfully, we researchers aren’t that far from our food source; meals on board the ship have been excellent.