Week 9, October 5-10, 2011, written by Joe Grzymski Excitement! Hard work! Incredible data!
Week 10 was never in our plan but somehow it ended up being one of the best weeks of science yet. Calm winds and cold temperatures continued to consolidate the sea ice over the weekend. On Monday Gram and Steve – members of the Search and Rescue team, roped up and tested the sea ice. They drilled holes to test the depth and consistency of the ice. It was between 8 and 12 inches thick and we were given permission to travel on the sea ice out to Station A. We sampled on it Monday in a test run for what turned out to be four days of sampling four times a day between 9am and 9pm.
Tuesday and Wednesday were marked with clear, relatively warm weather; the sunrises and sunsets were stunning (see Week 10 pictures on the Photos page). Thursday and Friday were marked by cloudier conditions, as a low-pressure system started to creep toward Palmer Station and bring a storm that would clear the ice out. This pattern is evident in the graph of solar irradiance – the lower graph (Figure 1). The first two days of the experiment, Tuesday and Wednesday, were bright with peak irradiances hitting 1000 μMol photons m-2 s-1, Thursday, when it became more overcast only reached 800 and on Friday it went down further with only a brief peak reaching 700 while most of the day was less than 600.
These irradiances are “captured” in our measurements of the maximum quantum yield of photosystem II (top panel, labeled FvFm which stands for variable fluorescence divided by maximum fluorescence. This is basically a “happiness” index for organisms that are photosynthesizing- the closer the value to 1 the happier they are. The values of Fv/Fm typically dip during the brightest times of the day. In our results Fv/Fm indeed dips after the brightest sun and then recovers at night. During these four days we sampled at 0900,1300,1700 & 2100 on Tuesday through Thursday. On Friday we sampled the earliest three time points and then had to shut the operation down due to high winds and rain. We collected 16 discrete samples of phytoplankton for microscopic, fluorometric, and nucleic acid analysis.
None of the work performed throughout the week would have been possible without the support of the search and rescue team lead by Gram and Steve or the support of each person who helped us sample. Thanks to everyone for your support. Photos from this great week are included above and on the Photos page.
Learn more at Antarctica.dri.edu