Lake Viedma, located in the Province of Santa Cruz, is the deepest in America and the fifth in the world. This recent discovery is the result of the work of a team of researchers coordinated by María Gabriela Lenzano, Ph.D. in Engineering from the National University of Cuyo. The group is made up of engineers from different specialties and a geographer from the Andean Geomatics Laboratory (LAGEAN) of the Institute of Nivology, Glaciology and Environmental Sciences of CONICET. According to her finding, the body of water studied is 900 meters deep and is located in an unexplored area of Los Glaciares National Park, until recently occupied by the Viedma glacier. The reduction of the ice surface from 2014 to the present has exposed the area to advance towards the lake.
The expedition led by Lenzano was financed by the Regional Center for Earth Sciences (ICEs) belonging to UNCUYO.
In dialogue with the University Supplement, the person in charge of LAGEAN, also a land surveying engineer from the National University of San Juan (UNSJ), explained that the team of researchers “approaches the numerical study of natural processes and carries out environmental monitoring, with an emphasis on the environment. of the glacier”.
-What led you to make this discovery in Lake Viedma?
-Actually, we have been making inroads for more than a decade in the region. The work in Lake Viedma is part of a series of investigations that we have carried out in Los Glaciares National Park. This task is based on measuring the depth of Lake Viedma from a boat and with special equipment. The bottom is not flat and we assume that it has a complex topography. We have entered the glacier since 2011. At that time it covered more space to the east; Even tourist excursions were made to walk on its surface. During the last few years, when the glacier began to recede, the companies canceled the excursions. The first bathymetry measurements (techniques to calculate depths) were made in 2014. The glacier descends from the southern Patagonian ice field (extension of continental ice in the Patagonian Andes, on the border of Argentina and Chile) and is part of the basin of the Santa Cruz River. It has regressed in a very important way. It has lost 5 square kilometers of surface and two kilometers longitudinally, approximately. In May of this year we decided to do another campaign to add new bathymetric measurements in the area recently abandoned by the glacier. At first, I was surprised by the results: 900 meters deep and 650 meters below sea level.
-What will this discovery allow you on a scientific level?
L-The discovery brings us a little closer to knowing what the bottom of the lake is like, where the glacier was resting until a few years ago. It allows us to have a 3D map, to see in which areas there are sediments. It can give us the opportunity to find out how the glacier behaves. We are going to work on that place.
Why do glaciers lose mass?
L-The glaciers of the southern ice field, in general, and of the world, have been losing mass since the mid-20th century due to climate change, but there are also local factors that cause the glaciers to behave in one way or another, according to where are they located. The Viedma glacier is not immune to these changes, its mass balance remains negative.
“It is quite a challenge to go to the study area and explore it, but we enjoy it. From the point of view of research, the behavior of glaciers in Patagonia presents a series of complexities that considerably nourish the studies that we develop”.
-What is the reason for glaciers to behave differently depending on the region?
L-In general, glaciers recede, but indeed it is local conditions that cause glaciers to behave differently from one basin to another. For example, within the Santa Cruz river basin, the Upsala glacier that ends in Lago Argentino and the Viedma glacier that ends in the lake of the same name have receded during the last century.
However, the Perito Moreno has a totally different behavior, at least until now. The Perito Moreno Glacier behaves like an oscillator. It advanced a kilometer about a century ago and acquired a position quite close to the Magellan Peninsula. Since then, limited by the surrounding topography, it has experienced small advances and retreats, in a range of less than 150 meters. When the glacier approaches the peninsula, it usually generates an ice dam. These events are part of the dynamics acquired during the last century, which generates frontal oscillations, composed of recurring cycles of advance and retreat of the front. The advance phases are from June to December and the backward phases, from December to April. Therefore, the progressive increase in this water level, in most cases culminates in an abrupt rupture of the dam, producing a sudden overflow of the volume of water to Lake Argentino, which causes the breakage of the dam. These ruptures are the tourist attraction of the glacier, where people go and take photos. A beautiful natural spectacle, in that beautiful glacier that is the Perito Moreno.
-How are the measurements made?
L-We did them from a boat provided by the National Parks Administration. We measure the depth of the lake with a sensor that emits a signal in the form of waves, which propagate through the aqueous medium until they reach the bottom of the lake and are reflected back on the surface. The device measures the time it takes for the wave to travel to an object and bounce back. This gives us the information of what is at a certain depth in that place.
-Why did you choose this region to investigate?
L-I started working in the Central Andes, in the Aconcagua National Park. For a decade, in general, my research has been focused on Patagonia. Personally, I work in science because I am passionate about asking myself questions, imagining. For us who live in Mendoza, getting to the work area means traveling 3,200 kilometers in a van. It is quite a challenge to go to the study area and explore it, but we enjoy it. From the research point of view, the behavior of the glaciers in Patagonia presents a series of complexities that considerably nourish the studies that we develop. We have been conducting research for a decade and have directed five doctoral theses in the area. I choose it personally and I can extend it to the entire LAGEAN team: the area caught us, it’s majestic.