Sims has trekked deep into the Virunga jungles to access the remote, and often active volcano Nyamulagira, and he repeatedly descended into the active Nyamulagira crater to collect old lava flows from the crater walls and molten magma from the active lava lake. Ecuador Sims has conducted numerous expeditions into the Ecuadorian volcanoes. Funded by the National Geographic Society in 2014, Sims led a month-long expedition into the remote Sangay volcano (5,300 meters/17,400 feet ASL), which is one of the highest and most continuously active volcanoes in the world. In 2016, while living in Ecuador for six months on a US Fulbright Scholarship, Sims conducted several two-week expeditions to collect samples on the steep, glacially dissected flanks and high-altitude ridges of Chimborazo (6,263 meters/20,548 feet ASL). Sims has also conducted and published NSF- and UW-funded research on the volcanoes Reventador, Sumaco, and the Chalupas Caldera. Mid-ocean ridges Sims has researched the petrology of mid-ocean ridges extensively. Sims worked on several research expeditions to 9-10°N East Pacific Rise aboard the WHOI operated Research Vessel (RV) Atlantis utilizing the U.S. Navy-owned Deep Submergence Vehicle (DSV) Alvin and other remotely operated (DSL-120 and Jason) and autonomous (ABE) vehicles to conduct his research. Sims has also sent his graduate students on research expeditions to the Kolbeinsey Ridge, the SW Indian Ridge, 45°N Mid Atlantic Ridge, and 9°03 East Pacific Rise. Yellowstone Wyoming is home to one of the world's super-volcanos, Yellowstone, which also happens to host the world's most profound, and visually stunning example of an active continental hydrothermal system. Since moving to Wyoming, Sims has been coordinating the introduction of novel geochemical and geophysical techniques to study Yellowstone's “geohydrobiology”, which is the study of how Earth, water and life connect. Other locations Sims’ research has also taken him to volcanoes in Italy (Mt. Etna and Stromboli), Nicaragua (Vulcan Masaya), Iceland (Hekla, Theistareykir, Krafla), Hawaii (Kilauea, Mauna Loa, Hualalai, Mauna Kea and Haleakala), and New Mexico (Jemez Volcanic Field, Zuni-Bandera, and Raton-Clayton Volcanic Field). Sims has worked on problems related to serpentinization and carbonization in Samail Ophiolite of Oman, and the Josephine Peridotite in Oregon. Public engagement Sims’ research and scientific expeditions have been featured in: National Geographic Magazine (October 2004; April 2011); GEO Magazine (October 2012; 2017); National Geographic Explorer Kids (October 2011); Oceanus (Fall, 2006); Popular Mechanics (October 2006); New Scientist (July 2008; December 2008); CNN ("Great Big Story"); MentalFloss (August 2013);