page_title: Lōʻihi Seamount
section_title: 1996 to present
hierarchical_section_title: Lōʻihi Seamount / Exploration / 1996 to present
caption_attribution_description: English: Ocean Bottom Observatory at Pele's Vent, Loihi Seamount
context_page_description: Lōʻihi Seamount is an active submarine volcano about 35 km off the southeast coast of the island of Hawaii. The top of the seamount is about 975 m below sea level. This seamount is on the flank of Mauna Loa, the largest shield volcano on Earth. Lōʻihi, meaning "long" in Hawaiian, is the newest volcano in the Hawaiian–Emperor seamount chain, a string of volcanoes that stretches about 6,200 km northwest of Lōʻihi. Unlike most active volcanoes in the Pacific Ocean that make up the active plate margins on the Pacific Ring of Fire, Lōʻihi and the other volcanoes of the Hawaiian–Emperor seamount chain are hotspot volcanoes and formed well away from the nearest plate boundary. Volcanoes in the Hawaiian Islands arise from the Hawaii hotspot, and as the youngest volcano in the chain, Lōʻihi is the only Hawaiian volcano in the deep submarine preshield stage of development.
  Lōʻihi began forming around 400,000 years ago and is expected to begin emerging above sea level about 10,000–100,000 years from now. At its summit, Lōʻihi Seamount stands more than 3,000 m above the seafloor, making it taller than Mount St. Helens was before its catastrophic 1980 eruption.
context_section_description: The bulk of information about Lōʻihi comes from dives made in response to the 1996 eruption. In a dive conducted almost immediately after seismic activity was reported, visibility was greatly reduced by high concentrations of displaced minerals and large floating mats of bacteria in the water. The bacteria that feed on the dissolved nutrients had already begun colonizing the new hydrothermal vents at Pele's Pit (formed from the collapse of the old ones), and may be indicators of the kinds of material ejected from the newly formed vents. They were carefully sampled for further analysis in a laboratory. An OBO briefly sat on the summit before a more permanent probe could be installed.
  Repeated multibeam bathymetric mapping was used to measure the changes in the summit following the 1996 collapse. Hydrothermal plume surveys confirmed changes in the energy, and dissolved minerals emanating from Lōʻihi. Hawaiʻi Undersea Research Laboratory, HURL's 2,000 m (6,562 ft) submersible Pisces V allowed scientists to sample the vent waters, microorganisms and hydrothermal mineral deposits.
  
  Since 2006, the Fe-Oxidizing Microbial Observatory (FeMO), funded by the National Science Foundation and Microbial Observatory Program, has led cruises to Lōʻihi investigate its microbiology every October. The first cruise, on the ship R/V Melville and exploiting the submersible JASON2, lasted from September 22 to October 9. These cruises study the large number of Fe-oxidizing bacteria that have colonized Lōʻihi. Lōʻihi's extensive vent system is characterized by a high concentration of CO2 and Iron, while being low in sulfide. These characteristics make a perfect environment for iron-oxidizing bacteria, called FeOB, to thrive in.
caption: Ocean bottom observatory (OBO) at Pele's Vents
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