Antarctica Bromocarbon Project Weekly Updates – Week Three

On Monday we went to our Western Erebus site for our first weekly sampling effort. The weather cooperated beautifully, and we were able to obtain all the samples that we needed, which involved coring 24! ice cores in one field work session. Our tents had also finally arrived allowing us to get out of the wind to process all the samples as needed. Sampling was followed by intense 24/7 hour lab work days to minimize disturbance to the bromocarbons and to capture microbial community signatures as close as possible to the time of sampling. Many hours were spent in the freezer-, cold- and rad lab to successfully process our samples for bromocarbon, microbial parameters, activity, metagenomics and proteomics. Our first bromocarbon profiles (see attached image) show very high levels of bromocarbons in the upper ice and snow (similar to winter values observed in 2018 resulting in the Nature paper). As expected, microbial activity values are low corresponding to the extremely low temperatures, snow cover and extreme ice thickness observed this year.  Moderate microbial activity found in seawater and under-ice platelet ice samples (see picture) show that our newly developed methods are working well.  For fast-changing enzymes and proteins in our proteomics samples we tested a new UVC killing method that kills the organisms immediately while still immured in the ice (before melting it) by using a XENEX UVC LED lamp. This method allows us to avoid using large amounts of melt chemicals (otherwise required). We were able to demonstrate that this new method indeed kills a majority of the activity in the samples (see attached picture).  Friday, we went out to the field again and obtained another set of samples that we are currently processing over the weekend. One of us (Emma) also gave another remote lecture about Antarctic life to a Seattle preschool group of 4 to 5-year-olds who were fascinated by all of it (see attached picture). Attached are some more pictures from our first weekly sampling campaign this week! 

Left: High bromocarbon concentrations in upper Sea Ice and Snow samples near McMurdo Station. Right: Radioactive Tritiated Leucine incorporated into Proteins at -1°C show that our UVC method is very effective in sterilizing the sample and reducing microbial activity in ice samples.

A group of Seattle preschoolers listening to a remote presentation by one of us from the Crairy Lab and the Aquarium.

Left: Our ice coring site in Western Erebus Bay. Right: The ice is almost 3 m thick! Shelly lifting the ice auger out of the hole.

Left: We use an Eskimo fishing tent to do our ice sectioning to stay out of the wind. Right: Image of the XENEX UVC irradiation lamp that kills microbes in our samples (inside the cooler depicted) before filtering them for proteomics.