At yesterday's science meeting, Dr. Randie Bundy (WHOI) and Dr. Kristen Buck (USF) presented information about ligand (iron-binding compounds) analysis and a general overview of the results of Incubation 1 and 3. If these presentations would have occurred four weeks ago, I am not sure I would have understood the information, but yesterday, I followed along with no problem. It goes to show the amount of information that I have learned during my time aboard the RVIB Palmer (and the patience and expertise of the science team and crew when answering my daily onslaught of questions).
It rained last night. Not just a sprinkle or a mist, but rain. There were also occasional periods of snow yesterday, adding to the approximately 3 feet of snow that sits atop the ice. The warmer conditions are not helping the forward progress of the ship because of that slushy layer that slows us down and makes it difficult for the ship to break ice in a constant motion. Although the conditions are not helping, we did make progress (gaining about a half mile) in the last 12 hours. The process is slow, but we are making progress, and that is what matters.
In a journal from mid-September titled Diatoms, Alexa Sterling (URI) introduced the term sea-ice diatoms. These are species of diatoms which attach themselves to floating sea ice using a type of mucus they produce. When the diatoms attach to the ice, the color of the ice changes from clear, light blue or white to a tan color. This is an indication that the ice is now home to millions of photosynthetic diatoms. You can see this brown coloration in the pictures of this journal, or in the first image of the 10-6-16 journal.
In the original research proposal, the science team requested the opportunity to sample ice. In the past few days, the science team expressed interest in collecting samples of sea ice from this area in order to analyze the ice (or water once it melts) and filter the water to collect biomass (biological material). We have seen this dirty ice throughout the research cruise. In our current location, we can see large amounts of this dirty ice as the ship creates a path and churns up the ice. It was decided that we might as well take advantage of our current situation and collect some of this sea ice.
The interest in sea-ice diatoms stems from the fact that this is the one area of the Antarctic marine ecosystem that is highly productive at this time of the year. These surface diatoms have received sunlight for longer periods of time than those that are currently deeper in the water column. This means, their biology and chemistry may be at a level similar to the incubation experiments that were conducted on the ship. Remember - the incubation experiments provide nutrients and light to the diatoms to analyze their productivity. Or, it could mean that the biology and chemistry are totally different because they are ice-bound versus moving through the mixed layer. Ice usually has slightly higher levels of iron, so there is also an interest in collecting ice and surface water samples to understand not only the types of diatoms, but how the chemistry affects their productivity, the presence of ligands, etc. It is amazing to think that these ice samples are capable of helping to answer many unknowns about the diatoms and ocean chemistry of this area.
Man Basket and Ice Ops
The best time to collect ice samples is when you are surrounded on all sides by ice, right? This was the logic behind the surface ice operations that occurred yesterday afternoon. The ice is too packed to launch the Zodiacs (small boats), so instead, the crew and the science team created a plan to use a piece of equipment called the man basket. I can only describe it as a cargo net wrapped around a circular base. The man basket was attached to the stern crane, the scientists and marine technician were attached to the man basket and away they went. This equipment was used instead of simply collecting ice from the side of the ship using a bucket or net. Samples from along the ship could be influenced (contaminated) by the metal hull. The use of the man basket allowed for the scientists to sample ice that did not come into contact with the ship.
Dr. Kristen Buck (USF), Dr. Bethany Jenkins (URI) and Marine Technician Jullie Jackson completed the operation in about 45 minutes. During that time, Dr. Buck and Dr. Jenkins collected large ice chunks along with surface water samples. MT Jullie Jackson directed the movement of the crane and ensured the safety of all three passengers. The images below tell the story of Surface Ice Ops.