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Letter from Nathalie Cabrol
From: Nathalie Cabrol ncabrol (at) arc.nasa.gov Subject: Mission Success Date: Wed, 22 Nov 2006 17:28:25 -0800 Dear all, We just spent one day in San Pedro de Atacama to relax (and take a shower!) after our return from the summit of Licancabur on November 20 and are now back at the refuge in Bolivia. We stayed 5 days and 4 nights in the mountain mostly around 5,916 m. While this was physically tough, the reward was immense as we successfully completed all of our science, including our two planned scuba dives in the summit lake of the volcano. The first one happened on November 19 and the second the following day in a water which at the surface was 4.7C and close to 0C at the deepest end, which we measured to be 16.27 ft. Words can hardly translate our feelings. Those dives were probably the most intense and peaceful moments in my life and I know that my diving companions Clay and Rob share the same feeling. There is so much we want to share with you but email is not the best way. We have videos and photos for each of the dives The first one was 31 minutes and the second 25 minutes. We completed all our planned science tasks, rehearsed so many times in the swimming pool at Ames in the past months. We also completed all the other science tasks not involving diving. Overall, we: Performed the first (and complete) bathymetry ever of the Licancabur lake using our portable 'in-house' bathymetric system, specifically a 50-cm long RC boat carrying a sonar, a GPS, and a thermal mapper. In 2004, we were able to complete only a small part of the lakeās bathynetry because of icing on most of it and last year, the lake was completely frozen over 80 cm depth. This year, we could see the profiles of the lake bottom unraveling in front of us on our computer screen in the crater as the bathymetric survey was happening. Including putting our boat together and surveying the entire lake (100 m x 90 m), the operation took about two-and-half hours. This step was critical for us to achieve since this map was the base document to pick investigation sites for the diving as well as locating our GPSed underwater samples on it. Basically, we want to be able to correlate our samples with their specific environments in the lake. The same system will be taken to Aguas Calientes in a few days to complete the bathymetry of that new summit lake as well; Repositioned our Eldonet station (UV dosimeter). We removed the station last year for maintenance. It is now back on and logging data (UVA, UVB, PAR, and temperature) for the next year; Performed UV point measurements in all channels. Since the beginning of the expedition, we have been recording daily values of UVA, UVB, UVC, and PAR between 4,500 m and 5,916 m (summit of Licancabur) as well as during our ascent of Escalante (5,700 m) last week. The results are fascinating and the UVC values stunning. They tell a lot about the radiation and geophysical environment for life; Serviced our meteorological stations. We were planning on retrieving our data from the past year but unfortunately, our batteries were stolen (yes, even at this altitude·) and the station stopped logging only three weeks after we had serviced it last year. This is disappointing and frustrating but we have taken steps to avoid this situation again; Performed plankton netting (20 micron net) to collect large amount of samples to characterize the diversity of microorganisms and larger organisms living in the lakes. In addition to Ames, 4 other labs worldwide are already asking for these samples in Canada, US, Argentina, Chile, and Australia. Performed limnological sampling (water samples and filtering) for studies at Ames; The other science activities took place underwater during our two scuba dives. The objective of the first one on Nov. 19 was to assess the diversity of life present in the lake. As soon as we entered the lake, it was obvious that there will be a need for much more campaigns just to grasp the complexity of the ecosystem. At least, a main question was answered about the potential for life survival and adaptation in this extreme lacustrine environment when we had to literally find our way through millions of copepods, small shrimps, and many other microorganisms and larger ones that I could not identify (I am a simple geologist after all). The videos will show that in greater detail than I can explain here. However, one observation, which was followed by sampling, stands up. We spotted a sort of white material seemingly deposited on rocks in shallow waters. We reach it and as I sampled it, I realized that underneath lied green algae. These samples will be heading back to Ames soon. Other algae on rocks in shallow waters showed a clear change in pigment with respect to their orientation to the surface, going from almost yellow green, to green, and then dark brown. These pigments usually indicate protection against UV. Weāll know more with the lab. The first dive was documented by a 35 minute video and many photographs; The objective of the second dive was to perform a full transect along the depth profile of the lake to sample sediment and water at every 50 cm depth increment until we reached the deepest part of the lake. We have now a full set of samples. During that second dive, I was holding the video camera underwater and filmed Rob collecting the samples and Clay photographing them. The video also is our first detailed video documentation of the entire Licancabur lake from underwater. It was very intense and peaceful at the same time. Holding that camera, I felt suspended between Heaven and Earth in the heart of this majestic emerald green crater lake. The experience was unique, whether physically, mentally, or spiritually. The science harvest is very promising. From 3 samples collected last year on the shores of Licancabur at very shallow depth (because the lake was frozen), DNA sequencing showed about 10-12% of new species and 70% of species somehow related (and not necessarily closely) to known species. This time, we have the entire depth profile. Letās see what the labs will tell us. Finally, in addition to the science, I would like to add that with our two dives at the summit lake of Licancabur, our team equaled the world record of highest altitude scuba diving established in the 80ās in the same lake. Moreover, we established a new world record of highest altitude scuba diving by using pure O2 rebreathers to perform our mission, which had never been done before that high. At our modest level, we tried to push the limits of human exploration of extreme environment a step farther. Our success broadens the range of extreme lakes that could now be reached now by the technique we developed and used. It is now getting late at the refuge, and cold. There was a short snow storm this afternoon. I will therefore end my message here for tonight. Since it is the season to give thanks, let me take the opportunity to express my gratitude to all of you who have supported our preparation for this very special expedition. Thanks for helping us by providing advice, support, whether technical, financial, scientific, or related to safety. None of this could have happened without you. A special thanks to Greg and the Stanford team for the hyper-professional help you gave us at a critical moment for the mission. Without your support, we could not have completed our mission. This success is also completely yours. While we have completed two of our three ascents, we still have Aguas Calientes to ascend in the coming few days. A new lake, a first time for us, in a volcano that could be as high as Licancabur. I am looking forward to sharing all of this with you when we come back home, which should be at the beginning of December. In the meantime, let me thank you again so much for your support and Happy Thanksgiving to all of you! Nathalie, Randy, and the gang of the thin air |
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