Lake Vida Expedition: Field Plan

In the field, the first step is the establishment of a field camp on the lake ice as there are no permanent structures anywhere near Lake Vida. The camp will include a large Polar Haven, in which all ice and sediment coring, all borehole cleaning, and brine sampling operations will take place.

The second step is drilling a hole in the 20 m ice cover as well as collecting and describing an ice core.

The third step corresponds to the implementation of an environmental protocol developed and tested in 2005 to avoid forward contamination to the lake. This protocol implies the detailed cleaning and sterilization of any hardware penetrating the lake water as well as the making of a distilled water ice sheathing of the top 14 meters of the borehole with less than 103 cells/mL. The latter is justified by the differences between the algae-rich organic matter of the ice cover and the sole presence of bacteria in the brine.

The fourth step is penetration of the lake body by drilling the last 6 meters of the ice cover and adjustment of the borehole head so the water column of the lake is not disturbed.

The fifth step is the characterization of the water column by CTD (conductivity, temperature, density) which also measures oxygen concentration and pH, electrochemistry, visual (camera). This step will provide the information necessary to constrain our sampling strategy [e.g. depth of sampling].

The sixth step is sampling of the brine (at a maximum of 10 depths).

The seventh step is an enlargement of the lower section of the borehole so that sediment coring can take place in a protective sleeve to avoid any mixing of the water column and limit disruption of the sediment/water interface to the specific area of coring.

The eighth step is sediment coring. We have three types or sediment coring devices with us as we do not know yet which one will be the best to use. The first one is a gravity corer, the second one is a push corer and the third one a piston corer.