Merry late Christmas! I hope everyone had and is continuing to have a great holiday. The holiday times here have been quite busy but very enjoyable all the same. The week leading up to Christmas was spent out on the Ross Ice Shelf testing the hot water drill along with the scientific instrumentation from each team that we will be deployed into Lake Whillans in under a month. Overall the test was a great success. It gave us insight into what we need to change in order to be more effective, along with letting us know what steps we don’t need to spend further time perfecting.
The hot water drill works by loading snow into a melt tank where heated glycol is passed through coils, which melt the snow upon contact. The melt water is pumped into a reservoir that holds approximately 17,000 liters (5500 gallons). Water from this holding tank is pumped into the Whillans Filtration Unit (WFU) where the water is filtered through a 2.0-micron filter, a 0.2-micron filter, and a bank of 254 nm and 185 nm ultraviolet radiation lights. The water is then passed to boiler tanks that heat the water to 88º C (190.4º F), which also essentially pasteurizes the water, in order to reach a maximum temperature for melting snow and ice to form the borehole. The entire filtration system is absolutely critical to the entire project. Lake Whillans is a subglacial lake that has never been breached before. In order to maintain the pristine conditions we must operate under environments that are almost sterile. The goal is to introduce fewer microorganisms than are actually present in the snow and ice that we are drilling through. During the test on the Ross Ice Shelf we discovered that the filtration system is very effective at reducing the concentration of viable organisms in the water that is being used for the hot water drilling.
One of the scientific instruments that are headed by LSU graduate student Amanda Achberger was also tested after the borehole was drilled through approximately 56 meters of ice. Amanda has worked on her sampler for quite some time and has tested it at Lake Tahoe along with several places around Louisiana. The sampler is designed to pull water through a three-tier set of filters concentrating any microorganism onto the filters, which are further analyzed after its deployment. The filters contain pores that are 10.0 microns, 3.0 microns, and 0.2 microns in size. The two larger filters are there mainly to keep larger particles and loose sediment from clogging the 0.2-micron filter, which would ultimately shut down the pump allowing less water to be filtered. During the test we successfully filtered approximately 300 liters of water!
One of the biggest difficulties we found while deploying on the ice shelf was the strong current we encountered once we passed through the ice. There was about 56 meters of ice followed by 900 meters of water until the ocean floor is reached; the currents that we experienced in that 900 meters was about 47 cm/sec.
Some of the other equipment that was deployed and tested was a multi-corer, a percussion corer, niskin water samplers, and a Conductivity, Temperature, Depth (CTD) sensor.
For my own project I will be getting sediment aliquots from instruments such as the multi-corer and the percussion corer that will obtain samples by coring into the bottom of Lake Whillans. I will use the sediment samples I receive from them and use those as inoculates for the enrichments that Dr. Christner and I have designed and tested over the last couple of years. To reiterate a bit, I will be setting up cultures that are specific for iron and sulfur oxidizing bacteria. Microorganisms use sulfur and iron as food sources by using the natural reduction processes that iron and sulfur undergo, and then oxidize the reduce forms and harness the energy that is used during the oxidation process. The main point to get from these types of cultures is that they do not need light as an energy source like many microorganisms do, but use alternative sources such as iron and sulfur to remain viable.
After Christmas the team that will be traversing the equipment the 450 miles to Lake Whillans began staging and lining up their caravan. Thirteen Challenger tractors will form up the traverse team making quite a sight to see! The traverse is dated to begin their journey on December 29th, 2012. Around the date of January 12th the rest of the scientific and drill teams will begin moving out what is left of the equipment and personnel to the field site. Drilling is slated to commence on January 19th.
So far everything is going as planned, wish us luck!