A S
Given the size of this project, and the remote area you are working in, it must attract a lot of attention. Are there any concerns by area residents about the project? What do the local communities think about your research?

S W
We have received a lot of attention not only from national and local media, but also from those living near the lake. The locals were particularly surprised to see huge cranes and other heavy equipment being transported through their villages to the project’s dock, where the gear was assembled into a working drilling barge. The confused locals thought that this equipment was owned by PT Vale Indonesia, a nickel-mining company operating nearby, which has often had a contentious relationship with the locals. Unfortunately for us, the words “drilling” and “project” also carry with them negative connotations. Within days after the project began, false rumors about our intentions started to spread widely. Some people that we met thought that we were going to do oil and gas exploration. Others were deeply concerned about the potential environmental impacts of the project; many asked us if a Lapindo-like mudflow disaster could happen because of our project.¹ The culmination was a demonstration staged by approximately 100 local residents and NGOs two weeks into the project. We listened to them, answered their questions, and worked hard to explain what the TDP really is. We were quite surprised with the moves against our scientific project, as Dr. Russell and Prof. Bijaksana had already held a meeting with the subdistrict head and local leaders two months prior to the start of the drilling. In addition, the district chief had known about this project since 2012, when it was still in the planning stage, but the information did not trickle down to area residents. The fact that 2015 was a busy year in politics, with elections of the district chief and village leaders looming, also added another complex dimension. We had already planned on doing outreach during our stay in Sulawesi, but the miscommunication with area residents forced us to go all out and work harder in conducting such activities. We held many meetings with various stakeholders: local leaders, government officials, local house of representative members, as well as representatives from NGOs. We also visited many elementary and high schools. In addition, we facilitated visits to our barge by government officials and locals alike, including school children, so that they may have a better understanding about our work. By the end, we were elated to learn that most locals had favorable views toward our project; many of them even expressed their open support.

E T
Regarding the drilling process itself, how long are the individual cores you are extracting from the lake bed? What condition do you extract them in (wet/dry, hard/soft, etc.)? And what will you do with this material next in order to study the samples collected?

S W
We hope to drill the sediment all the way down to the top of the bedrock. Lake Towuti’s water depth is approximately 200 meters, and the sediment underlying the water and overlying the bedrock has a depth of about 180 meters. To perform the drilling, we have to connect a bunch of five-meter-long drilling rods or pipes. When the actual drilling or coring equipment is lowered down through the inside of these rods, it brings along with it a three-meter section of plastic core liner. The drilled core sediment is captured in the core liner, and is prevented from falling back down by a core catcher when lifted up. Once the liner is out on the drilling barge, scientists cut it into smaller pieces (maximum length: 1.5 meters), put end-caps on both ends of the liners, and label them. Visual inspection suggests that the drilled wet sediments inside the core liners consist of different facies (for example bodies of rock with specified characteristics representing a certain  type of depositional environment), just as we had predicted before. We are able to see claydominated materials, sand-dominated materials, gravel-dominated layers, peat layers, as well as tephras (volcanic ash layers). The labeled sediment cores are then brought to the shore during our shift change, which happens twice a day. The cores are logged for magnetic susceptibility and other physical characteristics using a logger that we brought from Brown University and then temporarily stored in our field laboratory. We also sieve the sediment left in the core catcher and analyze these tiny samples under a microscope. The cores are currently on their way to the U.S. National Lacustrine Core Repository in Minnesota, where the scientists involved in the project will split them open into two halves during the core-splitting and sampling party later this year. The working halves will be photographed and logged for various physical characteristics using more sophisticated equipment and finally sub-sampled to be analyzed further by different scientists in their respective laboratories. Meanwhile, the archived cores will stay untouched in the repository in Minnesota.

E T
In our correspondence and previous meetings, you mentioned that the core samples you collect from Lake Towuti will provide up to 800,000 years of climate history. Can you explain more specifically how this climate knowledge is extracted from the sample? What sciences are involved in such processes of paleoclimatology?

S W
Paleoclimatology is the study of changes in climate taken on the scale of the entire Earth’s history. Humans started systematically collecting rainfall data from rain gauges and temperature data from thermometers only in the past few centuries. To obtain climate data from ancient times, we can use a variety of proxy methods borrowed from the Earth and Life Sciences that can tell us the amount of rainfall or temperature over a certain region during a certain period in the past. The physical, biological, and chemical characteristics of Lake Towuti’s sediment offer us clues of ancient climate history, which may help us understand the overall pattern of climate change and assist us in predicting how the climate might change in the future. For example, clay mineralogy may inform us of the types of materials that eroded easily and entered the lake, especially when the rainfall amount was high. During periods when the titanium level in Lake Towuti was higher than usual, for instance, we may deduce that those were relatively wet periods. Using pollens extracted from the sediment, then observed and counted under the microscope, we can learn about the types of plants that were living in the lake’s catchment area. Based on our pollen and leaf-wax carbon isotope analyses on the twelve-meter sediment cores from the 2010 expedition, we know that savannah was the dominant ecosystem in the area surrounding the lake between 33,000 and 16,000 years ago, during the last ice age. This indicates that the climate was much drier at that time. We hope to obtain environmental and climatic information further back in time using the longer drill cores from the TDP. One of our goals is to test whether the climate in the region was also dry during previous ice ages, and if so, why.