Kon-Tiki2 Expedition 2015-2016 Scientific Cruise Report

The Kon-Tiki2 Expedition was partly an anthropogenic exploration and partly an interdisciplinary oceanic and atmospheric research expedition. As a research expedition it was unique for three reasons: 1) The type of vessel used, 2) the timing of the expedition, and 3) the geographical location. The scientific program was run onboard the ancient design balsa rafts, powered by solar power only, with almost no possibility of stopping the raft, during a year with the strongest El Niño recorded in human history, in the midst of the center of that El Niño, namely in the area between Peru, Easter Island and the Chilean mid-latitudinal coast.\nThe scientific expedition planned and organized as a cooperation between the NIVA and NTNU in Norway. It was divided in two legs: the transect from Peru to Easter island and from Easter Island until the expedition concluded with the organized evacuation of the rafts. Instruments were brought on board the rafts and procedures were specifically developed for this cruise to study 1) climate change and ocean acidification, 2) marine litter, 3) El Niño and operational weather forecasting and 4) marine life.\nThe rafts were built following the designs of archeological studies on an Ecuadorian maritime culture known as the Manteno. They were built in Peru, with help from volunteers from all over the world as well as from the national Peruvian Navy. Building efforts were delayed by logistic issues, but Leg 1 departed Callao on November 7th 2015 and reached the Easter Island as planned 6 weeks later, on December 19th 2015. After a change of crew and a full overhaul of the rafts and equipment in Easter Island, Leg 2 departed Easter Island January 6 and ended March 17 2016.\nThe crew was multinational, gender-mixed, synergetic and multidisciplinary experienced. Each raft on each leg had 7 members on board. Only four members were present during both legs. There was a one scientist on board on each leg representing either of the organizing institutions.\nBoth rafts were instrumented for research. Each had an electrical installation with capacity calculated according to the payload of instruments that would be operated from it. Wind was the main source of energy to transport the vessels while photovoltaic cells transformed solar into electric energy for the electronics onboard.\nThe sensor payloads can be classified into three categories: atmospheric, oceanographic and ecological. Optical sensors to measure light, together with physical sensors to measure atmospheric conditions were combined with crew observations to describe the meteorological situation in the raft. A combination of echosounders and cameras were used to describe the macrofauna biodiversity present around the rafts. DNA and Chlorophyll a filtering aimed to study the microdiversity. The physical parameters like temperature, salinity, pH, levels of carbon dioxide described the climatic conditions in the region were the cruise sailed. Finally, both conventional and state-of-the-art technology were used to observe macro and micro plastics in this remote area of the world oceans.\nCurrently, the material collected on the cruise is subject of analysis in different laboratories. Kon-Tiki2, due to its unique nature, has been the subject of interest to a wide range of audiences. In addition to the general scientific interest, the expedition has given a much louder voice to the oceans than any regular research expedition could have given. For instance, the expedition coincided with the Climate Summit in Paris in December 2015 (COP21), a coincidence that we utilized to its fullest. The outreach efforts of the expedition participants have raised awareness about the science as well as about the expeditions sponsors. Most importantly, it has promoted cultural awareness across many state borders.\nThe Kon-Tiki2 Expedition combined science with adventure and challenge. Its organization was not simple, however, the outcome is of highest value, both from a professional scientific point of view, for the originator and sponsors of the expedition idea and for each and every project participant.\nKon-Tiki2 aimed to double-down on Thor Heyerdahl's Kon-Tiki voyage (1947) by sailing two rafts from South America to Polynesia and then back. No one has done this in modern history. Kon-Tiki2 was an unparalleled voyage of survival, science and exploration. Although one of the strongest El Niño ever recorded stopped us from sailing all the way to South America, Kon-Tiki2 substantiates the ancient Pacific pathway for both Polynesians and South Americans. We know both cultures had rafts. Polynesians probably used their superior double hulled canoe for exploration and rafts for migrations. Kon-tiki2 showed how Polynesians could have sailed to South America and back, and how South Americans could have done the same in the opposite direction.