Located in the Mariana Archipelago east of the Philippines, the Marianas Trench Marine National
Monument protects approximately 95,216 square miles of submerged lands and waters. This unique
place on Earth includes three units:
1. The Islands Unit
the waters and submerged lands of the three northernmost Mariana Islands.
2. The Volcanic Unit
the submerged lands within 1 nautical mile of 21 designated volcanic sites.
3. The Trench Unit
the submerged lands extending from the northern limit of the Exclusive Economic Zone of the United
States in the Commonwealth of the Northern Mariana Islands (CNMI) to the southern limit of the
Exclusive Economic Zone of the United States in the Territory of Guam. In the Islands Unit, unique reef habitats support marine biological communities dependent on basalt
rock foundations, unlike those throughout the remainder of the Pacific. These reefs and waters are among the most biologically diverse in the Western Pacific and include the greatest diversity of seamount and hydrothermal vent life yet discovered.
These reefs and waters are among the most biologically diverse in the Western Pacific and include the greatest diversity of seamount and hydrothermal vent life yet discovered.
They also contain one of the most
diverse collections of stony corals in the Western Pacific, including more than 300 species, higher than
any other U.S. reef area.The submerged caldera at Maug is one of only a few known places in the world where photosynthetic
and chemosynthetic communities of life co-exist. The caldera is some 1.5 miles wide and 820 feet
deep, an unusual depth for lagoons. The lava dome in the center of the crater rises to within 65 feet of
the surface.
Thus, coral reefs and microbial mats are spared much of the impact of these plumes and are growing nearby, complete with thriving tropical fish.
Hydrothermal vents at about 475 feet in depth along the northeast side of the dome spew
acidic water at scalding temperatures near the coral reef that quickly ascends to the sea surface. Thus, coral reefs and microbial mats are spared much of the impact of these plumes and are growing nearby,
complete with thriving tropical fish. As ocean acidification increases across the Earth, this caldera
offers scientists an opportunity to look into the future and ensure continuation of coral reef
communities.
The coral reef ecosystems within the Islands Unit have high numbers of apex predators, larger than
anywhere else along the Mariana Archipelago. One site has the highest density of sharks anywhere in
the Pacific, even higher than those of the remote islands of the Central Pacific.
Similarly, these northern islands have the highest large fish biomass in the Mariana Islands. The rare
bumphead parrotfish – the largest parrotfish species – thrives in these waters. The species has been
depleted throughout much of its range and is included on the IUCN Red List of Threatened Species.
The deepsea challenger used to explore the marianas trench and discover its secrets!
