An undergraduate eye-view of an Andean lake-coring expedition

August 25, 2017

Part 2: Progresso
by Molly Kingston (a BSc Biological Sciences student at Florida Institute of Technology, taking part in an expedition lead by Prof. Mark Bush)

With a fresh set of clothes and a shower after almost a week without one, it was time to set off for the next lake, Progresso.

Getting access to the lake required meeting not only with the landowner but with the entire town council. This process started on our trip North to Huayabamba. After playing volleyball with the local villagers for a while, we met with the town council to present to them what we wanted to do and why it was important. As darkness fell over the village of El Progresso, about twenty men and women gathered in a small house. A thunderstorm rolled around the valley and rain drummed on the tin roof. I have only taken three years of Spanish so it was hard to understand what was being said, but it was also cool to pick up on words that I knew and figure out what was being discussed. We had to convince them that we only wanted to take sediment from their lake and that we weren’t looking for gold or oil for the government. After an hour or so there were a lot of smiles and handshakes. It was agreed we could go to the lake, and even better there were five horses to help carry the gear. We left that night to continue north to core Lake Huayabamba.

Ten days later, we were poised to start work on Lake Progresso. We started out the day in a town called Chachapoya. We were scheduled to leave at 10:30 am but we were delayed by a parade going through town. All of the children were dressed in different traditional clothing. It was a unique glimpse into Peruvian culture.

After this two-hour delay, we finally made it to Progresso, but we knew that the late start meant we would be getting to the lake after dark. About 4 pm we started hiking while the horses were being packed up with our gear. This hike was a lot shorter than the one to Huayabamba, taking only about three hours. Also the lake was at 2000 m, which though still high, meant there was more oxygen than at Huayabamba. The trail, however, was either a constant uphill or downhill so it was really tiring.

It was after dark when we finally caught our first glimpse of the lake. The man who owned the lake was kind enough to let us use his camp. There was only enough room for two single tents and a kitchen area inside the barn, so we had to pitch 3 tents on the mossy ground surrounding the lake. The ground was very wet and it was hard to find a spot where we didn’t sink in, so the tents were packed close together.

Our first morning a preliminary bathymetry was performed before breakfast and indicated that the lake was only two meters deep. With this information, we took out materials to do a Universal Core. On our way to the center of the lake, we were delighted to discover that it was actually 12 m deep, and that the depth finder that was used that morning was malfunctioning.

While the core was being raised, one of the other girls and I worked on the limnology of the lake. To do this we had a YSI multimeter and a secchi disk. We lowered the sensor and recorded temperature, oxygen content, conductivity and salinity every meter until the bottom of the lake. The initial results indicated that the lake was not thermally stratified, and became anoxic in the 2nd m, suggesting strongly eutrophic conditions.

After we discovered that the lake was deep enough to obtain a good history, we set up the Colinvaux-Vohnout piston coring rig. I got to row all the people and equipment out. Being a collegiate rower, it’s cool to say that I’ve rowed in another country at elevations that we are not used to in the US.

Two of the anchors for the rig were tied to trees alongside the lake and the other anchor was a bag filled with rocks. After all of the anchors were set, I went back to shore to get one of the group members so we could do a more detailed bathymetric mapping of the lake. We used a fish finder that recorded water depth and GPS tracks of our sampling paths to map the lake.  I rowed us around trying to cover as much of the lake surface as possible. While we did this, other members of the group made notes about the botany of the forest around the lake. They found that lake was in a superbly sensitive position with lowland species at the upper edge of their range, and some upper Andean taxa near their lower limit.

The coring group was able to raise 9 m of sediment! But this didn’t come without a challenge. First, they had to hammer through a pretty solid section. Later in the lab we found a few chunks of rock in that drive, which was most likely what had slowed the coring. Secondly, the hole was lost, but they were able to find it again thankfully. After discussion that evening, it was determined that we would try to raise a parallel core the next day. We would have to wake up even earlier, however, because we also had to hike out that same afternoon.

I took a liking to coring, so I volunteered to help out. Unfortunately, one of the people going out with us had fallen in and had to go change into dry clothes. We couldn’t afford to waste a lot of time, so the two of us went out and started it. I got to stand on the platform and help with lowering and raising the tubes and drill string. It was one of the coolest things that I have done. If given the opportunity I would 100% do it again, even if it meant being stuck in the rain all day.

We successfully raised a parallel core with a couple hours to spare before we absolutely had to leave. With all of the stuff packed up, we headed back to the village. The hike back seemed to be more uphill than the hike there had been, but we did it in a shorter amount of time.

With a shower and pizza on the horizon, we concluded our journey into the Peruvian Andes. I will forever treasure the memories I made and the experiences I had. I can’t wait for my next trip back.

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