Mariana Trench

Mariana Trench Marine National Monument is a United States National Monument created by President George W. Bush on January 6, 2009, protecting approximately 95,216 square miles of submerged lands and waters in the Mariana Archipelago. The monument consists of three units: the Trench Unit encompassing the Mariana Trench, the Volcanic Unit protecting 21 designated submarine volcanic features, and the Islands Unit surrounding the three northernmost Mariana Islands. The monument is cooperatively managed by NOAA, US Fish and Wildlife Service, and the CNMI Government.

The monument protects extraordinary wildlife across vastly different environments. The Islands Unit features coral ecosystems with the highest large fish biomass in the Mariana Islands, including rare bumphead parrotfish and exceptional shark densities. Sea turtles, whales, and dolphins inhabit these waters. The Trench Unit sustains unique deep-sea life including Mariana snailfish, deep-sea jellyfish, giant amphipods, and translucent sea cucumbers under extreme pressure. The Volcanic Unit's hydrothermal vents support chemosynthetic communities unlike anywhere else on Earth.

The Islands Unit contains pristine coral reef ecosystems with high coral coverage on basalt foundations, unlike typical Pacific reefs. These unique habitats support marine biological communities adapted to volcanic substrates. The deep-sea portions lack photosynthetic organisms but support bacterial mats and chemosynthetic communities that form the base of food webs independent of sunlight. The extreme environments of the trench and volcanic vents host microorganisms and unique life forms adapted to conditions that would be lethal to most species.

The monument protects some of Earth's most extreme geological features. The Mariana Trench reaches depths of nearly 36,000 feet at Challenger Deep, the deepest point on Earth. The Volcanic Unit includes 21 submarine mud volcanoes and hydrothermal vents along the Mariana Arc of Fire. The Champagne hydrothermal vent produces nearly pure liquid carbon dioxide, one of only two known sites in the world. A unique pool of liquid sulfur exists at Daikoku submarine volcano. These features result from Pacific plate subduction beneath the Philippine plate.

Surface waters in the monument area experience tropical Pacific conditions with warm temperatures and distinct wet and dry seasons. However, the monument's primary features exist far below where surface conditions matter. The deep trench experiences constant near-freezing temperatures and complete darkness. The volcanic vents create localized extremes with boiling, highly acidic water. The Islands Unit's surface waters remain warm year-round, supporting coral reef development. Climate change may affect surface ecosystems while deep features remain relatively stable.

The Chamorro people have inhabited the Mariana Islands for thousands of years, though the monument's remote islands and deep-sea features were largely inaccessible. Scientific exploration has revealed the trench's wonders only in recent decades. The Challenger Deep was first sounded in 1875 and first reached by humans in 1960 when Jacques Piccard and Don Walsh descended in the Trieste bathyscaphe. Subsequent expeditions have expanded understanding of these extreme environments. The monument designation recognizes both scientific importance and the need for protection.

Mariana Trench Marine National Monument was established by Presidential Proclamation on January 6, 2009, by President George W. Bush. The monument is cooperatively managed by the Secretary of Commerce through NOAA, the Secretary of the Interior through the US Fish and Wildlife Service, and the CNMI Government, with coordination involving the Department of Defense and Department of State. A final management plan was published in 2024. The monument protects globally significant geological and biological features for scientific study and conservation.

The monument protects features largely inaccessible to casual visitors due to extreme depths and remote locations. The Islands Unit's pristine reefs offer exceptional diving for those who can arrange access. Scientific expeditions have captured stunning imagery of the deep features. The Mariana Trench's Challenger Deep represents the ultimate exploration challenge. The submarine volcanoes and hydrothermal vents showcase Earth's dynamic geology. The monument's significance lies in protecting these features for science and future generations rather than recreational access.

The monument's extreme depths and remote locations make most areas inaccessible to visitors. The Islands Unit surrounding Farallon de Pajaros, Maug, and Asuncion is approximately 50 nautical miles from these uninhabited islands. Access requires specialized vessels and permits. There are no visitor facilities within the monument. Scientific research expeditions require extensive planning and resources. The trench and volcanic features can only be reached by submersibles or deep-sea equipment. The monument is protected for its scientific and conservation values.

The monument protects globally unique ecosystems including the deepest place on Earth and extraordinary hydrothermal environments. The remote Islands Unit maintains pristine coral reefs with apex predator populations unmatched elsewhere. Protection from fishing and resource extraction allows these ecosystems to serve as baselines for understanding ocean health. Scientific research within the monument expands understanding of extreme environments and life's adaptability. The 2024 management plan guides cooperative stewardship of these irreplaceable resources for future generations.