We gained two more members to our team this week; Conor Sullivan, a field technician with the Ducklow group at the Lamont-Doherty Earth Observatory, and Ribanna Dietrich, a graduate student at the University of Edinburgh in Scotland. After dropping them off (along with a massive quantity of cargo) the Gould made a fast departure to start a four-week research cruise to study fjord processes along the West Antarctic Peninsula. Fjords are a major feature of the coastline, but haven’t received a lot of study due to the difficulty of safe access and the limited available resources. When the Gould comes back around it will be time for Jamie Collins and I to return to Punta Arenas.
Now that we have a full team it’s time to ramp up our sampling schedule. We’ve been pretty busy so far; in addition to our ice removal experiment we’ve already made it out to the regular Palmer LTER sampling sites by zodiac a couple of times. This three minute video, taken on the nicest day anyone on the team can remember having in Antarctica, highlights some of the challenges of conducting a full oceanographic sampling program from a 19 foot zodiac.
Unfortunately most days this season have looked nothing like the day in the video. As Jamie discusses in his blog here, the winds have been unusually strong this year. That’s kept the phytoplankton bloom from developing and mostly kept us on shore (boating operations shut down when the wind reaches 20 knots).
Contrary to all expectations however, the strong winds this season haven’t broken up the land fast ice in Arthur Harbor. Over a week ago I reported on our “last” visit to our ice station. With the ice in good shape we were able to make another sampling foray yesterday. I’m glad that we did, because a diatom bloom is starting to develop under the ice! The exciting thing about that is that it’s exactly what we would expect to find. The sea ice stabilizes the water column and keeps the diatoms from getting mixed too deep. For many years researchers, relying primarily on satellite observations of chlorophyll a in the surface ocean, have hypothesized that the presence of sea ice plays an important role in high latitude phytoplankton bloom formation. Direct observations of this however, are sparse. This year, purely by chance, we’ve got the opportunity to observe a well-stabilized water column underneath sea ice adjacent to a highly mixed water column in open water.
These are the first centric diatoms that we’ve seen this season, and they are quite abundant under the ice right now.
Also not previously observed this season, this is a delicate chain of pennate diatoms morphologically similar to the genus Pseudo-nitzschia.
Another chain forming diatom; this was the first diatom (genus Chaetoceros) that we observed responding to the springtime conditions under the ice. It’s a little less abundant now.
Happy Thanksgiving!
