Sampling diatoms and mud in lakes of Ecuador
Together with my lab colleague Melina, and Sara, we crossed most of this beautiful Andean country from north to south, and from high to low elevation lakes in 25 days full of water and mud! Along the trip, we have had the opportunity to join with amazing Ecuadorean collaborators, including researchers from University of Cuenca and ETAPA (Henni Hampel and Pablo Mosquera), IKIAM University (Jorge Celi) and ESPOCH (Luis Quevedo). The objective of this fieldwork trip was to sample modern diatoms and lake sediments for (paleo)limnological studies, funded by a National Geographic grant lead by Prof Sheri Fritz, who also did fieldwork the first week with us, together with our close collaborator Paul Baker. In addition, our Ecuadorean super active collaborator Miriam Steinitz-Kannan joined us for the stretch sampling in Cuenca.
We spent the first week (2-8 July) in Imbabura province sampling Yahuarcocha and Piñan lakes.
Yahuarcocha is a well-known lake, located at the Internandean valley. Local people commonly named 'laguna de sangre' because its waters became red in historical times. The bacteria, Euglena sanguinea, caused this shift in the lake waters, associated with a combination of limnological factors such as anoxia and low water levels that thrive blooms of this microorganism. The sediments we recovered (4m of mud) showed reddish bands that might indicate episodes in which such limnological conditions occurred as result of climatic variability.
We dedicated the last days in Imbabura province to travel until Piñan community (4-hours drive), where we sampled a glacial lake located at 3400 meters above sea level surrounded by Páramo vegetation. There, we recovered a very nice 70-cm core that will be used as analogue for the Paramo lakes situated further south in Ecuador, at the Cajas National Park, Cuenca.
The sampling in Cajas (9-15 July) was really amazing, cold and exhausting though. We would like to thank specially the help received by Pablo Mosquera, a technician biologist from ETAPA, the public water company of Cuenca, who not only arranged all the logistics for the trip there (permits, car, accommodation), but also guided us throughout the National Park to reach the most wonderful selection of its lakes, and he taught the landscape history of the park that is not as pristine as thought: damming, trout farms, eutrophication, land uses changes (fires), etc. A total of 9 lakes were sampled (in chronological order): Estrellascocha, Jigeno, Torreadora, Marmolcocha, Patoquinoas, Piñancocha, Riñoncocha (kidney shaped lake), Fondococha and Dos Chorreras. Also, it is must to mention the special help received by Don Simon and his two friendly horses for carrying the scientific gear.
After the highlands, we headed up to the lowlands, in the Napo province of Ecuador (15-19 July). The objective were to sample 4 lakes floodplain lakes: Gardazacocha, Mandicocha, Añangucocha and Limoncocha. We had the unmeasurable help of local people to reach the lakes with canoes. All of the lakes suffered human impacts since the 80's with the construction of touristic lodges surrounding them. Nowadays, touristic cabins with all of kind of activities and accommodations are the most typical picture of the Napo lakes. We intend to reconstruct these impacts by analyzing the sediments and compare pre-human impact with modern data (we have some evidences already that blue-green algae have developed in Limoncocha, and they were not present in the past!).
Our last stop was in Riobamba (19-24 July), in Chimborazo province, at the center of country. Riobamba was the region where Ecuador was built as a country, having its first parliament. With 14 lakes sampled in our backs, here we wanted to core Laguna Colta, a shallow lake with two very different basins in terms of human activities; we sampled the two of them after being told that one is dredged periodically, and the other is apparently less impacted - so good basis for comparison. The second day we headed up to the Sangay NP to sample and core Atillo lakes. We wanted to do a couple of them, including Laguna Negra. After seeing its rocky steep slopes, this lake promised good adventures! We found a very deep lake (more than 40m of water column throughout), which unfortunately we couldn't took a sediment core rather than good modern samples (there were no previous diatoms studies in Atillo lakes). Instead, we recovered a very nice core from Kuyuk lake, a nearby lake that forms an interesting lacustrine complex of several lakes connected among them: Laguna Magdalena and Laguna Atillo.
Overall, 16 lakes, more than 1,000 1-cm mud slices, 32 modern diatom samples (periphyton and phytoplankton), and associated water physicochemistry data that cover most of the Ecuador ecosystems: Andes, Interandean valley and Amazonia. Lot of hours are waiting us into the lab and microscope! After that, the real fun starts!