by Nathalie Cabrol
We are starting to get used to the local weather pattern of morning sun and afternoon storms. We wake up in calm, crystal clear air, deep blue sky, and warming sun. By 11:30 am, the wind starts to pick up and wavelets form on the lake. By 1:30 pm, cumulo-nimbus clouds accumulate in the sky and by lunchtime, rumbling echoes in the valleys and mountains all around us. The sky is deep black, and for about two hours, thunder reigns over us. Yesterday was especially impressive. The mountains around us disappeared for a couple of hours to reappear draped in an immaculate white coat of snow. Because of our altitude, we only had rain, but it was intense at times. We also had hail for about 10 minutes. The good news is that our domes are holding up. No water inside! After dinner, the calm had succeeded the storm and the constellation of Orion could be seen upside down over our camp while Venus was setting to the west. What an amazing landscape. I am in awe. The power that nature unleashes gives us our true dimension. Without the large buildings to protect us, the technology, and all what our civilization has generated, we are naked in front of her. Yet, we are strong enough to tip her balance, and hopefully we will be smart enough to understand how to repair the damage, or at least mitigate its worst consequences for future generations.
These thoughts cross my mind this morning as I enter the lake. I am going with Gordon. Our goal is to do a reconnaissance of the shore but also go to the pontoon where Planetary Lake Lander is now setting. We go to the pontoon first. It is anchored maybe 100 m off shore. I enter the water and immediately connect with the forest of macrophytes. I have developed a technique to avoid entanglement. It is not pretty, but it works. I push the algae sidewise and make my way past them. There, I meet trout and granite blocks. The water is already over 5 meters deep. I am now making my way towards the pontoon and all of a sudden, it surrounds me, a deep dark blue. It is everywhere around me, enveloping me. I feel in another dimension, without any landmarks to keep my bearings. I just know the pontoon is 100 meters in front of me, somewhere. What a strange feeling. In a water so clear, the abyssal depth of this lake makes any sense of space and time disappear. I am floating between dimensions, with only the rhythm of my fins to let me know that there is a destination to this journey.
Then it comes. The sun must have reappeared from behind the clouds. Its rays passes through this water as if it did not exist. I can see every single one of them. I look below into the deep blue and I realize that I am casting a shadow in this no-man’s land. A white line appears in front of me, one of the anchor lines of the pontoon. We are there. I surface and see our probe right in front of me, surrounded by two red buoys. We swim around, look at the attachment points and move back to the near shore area.
We spend nearly an hour exploring the shelf. I notice some very bright yellow deposits on the silty sediment. Where does it come from? I will have to ask my Spanish colleagues who are currently documenting the biology of Laguna Negra. I plan to sample this sediment but I need to get back to camp for that. That will wait until we are finished with Gordon. He wants underwater footage and for several minutes we play hide and seek behind the algae. I am following fish and while doing so, I see black deposits on the bottom.
All right, I am getting out of the water and heading back to camp. I am fetching a couple of sample bottles and make my way back into the water. I spent the morning without a lead belt but this time, this will not work for sampling. So, more adjustments and with 4 kg of lead, I have no difficulty hitting the bottom with my 5.3 mm suit. A trout looks at me while I am sampling. I am pretty sure of what she thinks but she is polite enough not to let me know. Instead, she is taking advantage of the stirred sediment to have an early lunch. What I sample looks like black goo. Once at the surface, I definitely cannot miss the sulfur smell. More samples. I am trying to get back to the water for the yellow deposits. I am getting very cold. My hands are mostly numb now and I start cramping while going down. Time to get out. More than an hour in a 13C water is taxing, even with an excellent suit. The morning has been more than productive.
While we were exploring the abysses, Chris and Liam were exploring the northwest shore for possible landings and radio tests. Both were successful. Tomorrow, we are heading to the Echaurren valley on that part of the lake. Our objective will be to deploy our meteorological station, the stream gauge, and the UV dosimeter. If we have time, we will go up to the runoff produced by the melting of the ice in the rock glacier at the base of Echaurren.
Finally, Chris also took advantage of the exploration of the northwest shore to acquire some more bathymetry. The deepest low for now is close to 270 m and I am not sure we have seen the end of it. As I am getting more acquainted with Laguna Negra, I still do not know if I want to think of this lake as the Deep Blue or the Abyss. Its depth tells the tale of a time, not so long ago, when a formidable glacier was carving its way through this valley. The ice has given way to water where, for now, we stay suspended looking for answers.