The diverse natural landscapes of central Indonesia inspired Alfred Russel Wallace to conceive of natural selection and biogeography theories, yet the region’s long-term climatic and environmental histories are virtually unknown. From May to July 2015, the Towuti Drilling Project (TDP)—the first lake drilling project anywhere in Southeast Asia—conducted an international scientific expedition to drill into the sediment underneath Lake Towuti in South Sulawesi. The obtained drill cores will be used to reconstruct the climatic and environmental evolution of central Indonesia during the past 800 millennia through biogeochemical and physical analyses. Simultaneously, this research highlights the natural processes that helped generate the landscapes Wallace saw during his own expedition between 1854 and 1862. Anna-Sophie first met Satrio, then Project Coordinator of the TDP and a Ph.D. student at Brown University, during the 12th Northeastern Conference on Indonesia at Cornell University in the fall of 2014. After an ongoing email correspondence about the unique research, and a failed visit to Lake Towuti in June 2015, we had the chance to speak about his research on the occasion of 125,660 Specimens of Natural History.

A S
Can you explain the origins of the Towuti Drilling Project? What began your research in this region of Sulawesi? Why is this area important? And what is the overall aim of the project?

S W
The Indonesian archipelago and the seas surrounding it are a major source of global water vapor and heat, and therefore play a crucial role in the global climate system. A better understanding of the convection and precipitation mechanisms around the archipelago over time will not only give us a better idea of what Indonesia’s precipitation will look like in the future but also give us deeper insight into the past, present, and future of the global climate system. Unfortunately, there are only limited climate data available from Indonesia. Based on our previous research, Lake Towuti, located at the heart of the Indonesian archipelago, contains hundreds of meters of sediment that can be used to reconstruct climatic and environmental changes during the last circa 800,000 years, the only known such record from the region. The Towuti Drilling Project is the first scientific continental drilling project in Southeast Asia, and from a paleoclimatic perspective, its location is just perfect. My Ph.D. advisor at Brown, Dr. James Russell, first envisioned the TDP about a decade ago, when he started working in the Indonesian region. As an expert on both past tropical climates and lake ecosystems, he is interested in reconstructing and deciphering climate and environmental information contained within layers of mud buried underneath tropical lakes. Together with Prof. Satria Bijaksana from Institut Teknologi Bandung, James started some preliminary research at Towuti and surrounding lakes in 2007. After multiple fieldwork sessions and analyses of preliminary data, the two of them, along with their collaborators, began writing a proposal for the drilling project in 2012.

E T
You mentioned previously that you have done research in the region prior to this project—can you tell us more about how you prepared?

S W
We conducted seismic expeditions in 2007, 2010, and 2013, as well as a coring expedition in 2010. Seismic analyses are needed to scan the sediment underneath the lake. The “air-gun” system, which produces seismic reflection data, is akin to ultrasounds often used with pregnant women. It allows us to detect the thickness of the mud that has accumulated on top of the lake’s bedrock for almost one million years. Using these data, we were able to identify potential sites for coring/drilling. The 2010 coring expedition gave us several piston cores from Lake Towuti. Each was about twelve meters long, and their base was dated to approximately 60,000 years ago. We have done various physical, biological, and chemical analyses on these cores, and our results suggest major environmental and climatic changes in the region during that period. These results confirmed our conviction that Lake Towuti is indeed a great site to study the climatic and environmental changes of Indonesia. Now, with our newly recovered cores from the TDP, we hope to capture and understand the major changes that might have occurred further back in time.

E T
In his day, all Alfred Russel Wallace needed was a letter from the Dutch in order to collect his specimens in Nusantara; over 150 years later, your legal requirements are much more substantial. Also, the setup for such a drilling project is extremely complicated. Can you give us a sense of the logistics involved in doing this kind of research?

S W
As the TDP is an international effort, up to twenty-five foreign researchers were involved in the actual drilling operation. We had to complete plenty of paperwork for various governmental institutions and at different levels of government. We also brought in multiple containers and major drilling and research equipment from the U.S. and Germany. These containers and the drilling rig are quite big, and there were only a few vehicles and cranes that could be used to transport them to our dock once they arrived in Sulawesi. We had to coordinate with various shipping and transportation contractors to help with the movement of our equipment. Due to technical difficulties in the middle of our project, the project had to be extended by about two weeks, and we shipped in spare parts for our hydraulic pumps from the U.S. They were not easy to locate and eventually arrived safely in Sulawesi, but the journey was not without hiccups. Finally, the delay in our departure from Sulawesi caused us some problems, as it forced us to reschedule the demobilization of our equipment and rebook our return tickets. Neither task was easy given that our final departure date was so close to Idul Fitri, a major holiday in Indonesia.

A S
You are not the only scientist presently working at the Towuti Drilling site. Can you tell us about your team? What scientific fields are your colleagues working in, and what they are looking for? More specifically, what it is that you are hoping most to find?

S W
There are about thirty scientists working either at the site or the on-shore laboratory during the drilling project. The scientists, led by Dr. Russell and Prof. Bijaksana, come from five countries and have different scientific backgrounds. Some of us, like myself, are interested in climate questions. How has rainfall history evolved since the lake was formed? What caused rainfall patterns to vary? What was the environmental response to changes in climate over time? We are using various proxy data extracted from the sediment cores to answer these questions. A few scientists involved in TDP are interested in the geological processes that formed the lake. They want to determine the age of the lake, as well as the evolution of its physical form over time. For instance, we saw a sequence of soil, river sediment, peat, and lake sediment in some of our drilling sites, therefore allowing us to deduce the geological evolution of the lake, as well as how the water level might have varied over time. We also found several thick volcanic ash layers, which might have originated from volcanic eruptions in northern Sulawesi. If these layers can be tied to previously identified volcanic ash layers from the region, they can be used as time-horizon markers. Lake Towuti also hosts many endemic species and is surrounded by one of the most diverse rainforests on Earth. The biologists among us are especially interested in finding microfossils from the sediment, which may help them understand the rates of biological evolution, as well as the sensitivity and resilience of Towuti’s aquatic and rainforest ecosystems to climatic and environmental changes. Finally, several biogeochemists are also involved in this project. Lake Towuti is among the world’s largest iron-rich lakes. The ophiolite bedrock surrounding the lake supplies metals that drive important biogeochemical processes. Drill cores allow us to expand our understanding of these processes and closely study the impact of climate changes on environmental chemistry. By doing so, we hope to improve our knowledge on how to maintain a sustainable Towuti ecosystem in light of recent changes in climate and human land-use.