The Aquarius Reef Base is an
underwater habitat
Underwater habitats are underwater structures in which people can live for extended periods and carry out most of the Circadian rhythm, basic human functions of a 24-hour day, such as working, resting, eating, attending to personal hygiene, and ...
located off
Key Largo in the
Florida Keys National Marine Sanctuary, Florida, United States. It is the world's only undersea research laboratory and it is operated by
Florida International University
Florida International University (FIU) is a public research university with its main campus in Westchester, Florida, United States. Founded in 1965 by the Florida Legislature, the school opened to students in 1972. FIU is the third-largest univ ...
. It is deployed on the ocean floor below the surface and next to a deep coral reef named
Conch Reef.
Aquarius is the only undersea research laboratory currently in operation, although the Marine Resources Development Foundation used to operate two additional undersea facilities, also located in Key Largo, Florida. Aquarius was owned by the
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, ...
(NOAA) and operated by the
University of North Carolina Wilmington
The University of North Carolina Wilmington, or University of North Carolina at Wilmington, (UNC Wilmington or UNCW) is a Public university, public research university in Wilmington, North Carolina. It is part of the University of North Caroli ...
until 2013 when
Florida International University
Florida International University (FIU) is a public research university with its main campus in Westchester, Florida, United States. Founded in 1965 by the Florida Legislature, the school opened to students in 1972. FIU is the third-largest univ ...
assumed operational control.
Florida International University (FIU) took ownership of Aquarius in October 2014. As part of the FIU Marine Education and Research Initiative, the Medina Aquarius Program is dedicated to the study and preservation of
marine ecosystems
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the sur ...
worldwide and is enhancing the scope and impact of FIU on research, educational outreach, technology development, and professional training. At the heart of the program is the Aquarius Reef Base.
Purpose
Aquarius, designed by Perry Submarine Builders of Florida and constructed by Victoria Machine Works, was built in
Victoria,
Texas
Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
, in 1986.
Its original name was "the
George F. Bond", after the
United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
physician who was the father of
SEALAB
SEALAB I, II, and III were experimental underwater habitats developed and deployed by the United States Navy during the 1960s to prove the viability of saturation diving and humans living in isolation for extended periods of time. The knowledge ...
in particular and
saturation diving
Saturation diving is an ambient pressure diving technique which allows a diver to remain at working depth for extended periods during which the body tissues become solubility, saturated with metabolically inert gas from the breathing gas mixture ...
in general.
Underwater operations were first planned for Catalina Island, California, but were moved to the
U.S. Virgin Islands
The United States Virgin Islands, officially the Virgin Islands of the United States, are a group of Caribbean islands and a territory of the United States. The islands are geographically part of the Virgin Islands archipelago and are located ...
. Following
Hurricane Hugo
Hurricane Hugo was a powerful tropical cyclone that inflicted widespread destruction across the northeastern Caribbean and the Southeastern United States in September 1989. The eleventh tropical cyclone, eighth Tropical cyclone naming, named st ...
in 1989, Aquarius was taken to Wilmington, North Carolina, for repairs and refurbishment and was redeployed in the Florida Keys in 1993. Aquarius is located under of water at the base of a
coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...
within the
Florida Keys National Marine Sanctuary, an ideal site for studying the health of sensitive
coral reefs
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
...
.
The laboratory is most often used by marine biologists for whom Aquarius acts as home base as they study the coral reef, the fish and aquatic plants that live nearby and the composition of the surrounding seawater. Aquarius houses sophisticated lab equipment and computers, enabling scientists to perform research and process samples without leaving their underwater facilities.
The habitat accommodates four scientists and two technicians for missions averaging ten days. Scientists on the Aquarius are often called "
aquanauts" (as they live underwater at depth pressure for a period equal to or greater than 24 continuous hours without returning to the surface). A technique known as
saturation diving
Saturation diving is an ambient pressure diving technique which allows a diver to remain at working depth for extended periods during which the body tissues become solubility, saturated with metabolically inert gas from the breathing gas mixture ...
allows the aquanauts to live and work underwater for days or weeks at a time. After twenty-four hours underwater at any depth, the human body becomes saturated with dissolved gas. With saturation diving, divers can accurately predict exactly how much time they need to decompress before returning to the surface. This information limits the risk of
decompression sickness
Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from Solution (chemistry), solution as bubbles inside the body tissues during D ...
. By living in the Aquarius habitat and working at the same depth on the ocean floor, Aquarius aquanauts are able to remain underwater for the duration of their mission. In addition, because Aquarius allows saturation diving, dives from the habitat can last for up to nine hours at a time; by comparison, surface dives usually last between one and two hours. These long dive times allow for observation that would not otherwise be possible. Way stations on the reef outside Aquarius allow aquanauts to refill their scuba tanks during dives.
Habitat structure
Aquarius consists of three compartments. Access to the water is made via the wet porch, a chamber equipped with a
moon pool
A moon pool is an equipment deployment and retrieval feature used by oil platforms, marine drilling platforms, drillships, diving support vessels, fishing vessels, oceanography, marine research and underwater exploration or research vessels, and ...
, which keeps the air pressure inside the wet porch the same as the water pressure at that depth (
ambient pressure
The ambient pressure on an object is the pressure of the surrounding medium, such as a gas or liquid, in contact with the object.
Atmosphere
Within the atmosphere, the ambient pressure decreases as elevation increases. By measuring ambient atmosp ...
), about 2.6
atmospheres, through
hydrostatic equilibrium
In fluid mechanics, hydrostatic equilibrium, also called hydrostatic balance and hydrostasy, is the condition of a fluid or plastic solid at rest, which occurs when external forces, such as gravity, are balanced by a pressure-gradient force. I ...
. The main compartment is strong enough, like a submarine, to maintain normal
atmospheric pressure
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013. ...
; it can also be pressurized to ambient pressure, and is usually held at a pressure in between. The smallest compartment, the Entry Lock, is between the other two and functions as an
airlock
An airlock is a room or compartment which permits passage between environments of differing atmospheric pressure or composition, while minimizing the changing of pressure or composition between the differing environments.
An airlock consist ...
in which personnel wait while pressure is adjusted to match either the wet porch or the main compartment.

This design enables personnel to return to the surface without the need for a
decompression chamber when they get there. Personnel stay inside the main compartment for 17 hours before ascending as the pressure is slowly reduced, so that they do not suffer
decompression sickness
Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from Solution (chemistry), solution as bubbles inside the body tissues during D ...
after the ascent.
Underwater missions and research
Several missions on the Aquarius have been canceled due to
hurricane
A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its ...
activity. During
Hurricane Gordon in 1994, a crew of scientists and divers had to evacuate Aquarius and climb up a rescue line to the surface in seas after one of the habitat's generators caught fire.
In 1998,
Hurricane Georges nearly destroyed Aquarius, breaking a joint in one of its legs and moving two weights on the wet porch nearly off the structure. Both Hurricane Georges and
Hurricane Mitch
Hurricane Mitch was an extremely deadly and catastrophic Atlantic hurricane, which became the second-deadliest tropical cyclone in the Atlantic basin on record. Mitch caused 11,374 fatalities in Central America in 1998, including approximately ...
, later in 1998, also destroyed way stations outside Aquarius used to refill aquanauts' scuba tanks.
In 2005,
Hurricane Rita
Hurricane Rita was the most intense tropical cyclone on record in the Gulf of Mexico, tying with Hurricane Milton in 2024 Atlantic hurricane season, 2024, as well as being the fourth-most intense Atlantic hurricane ever recorded. Part of the ...
broke two of the habitat's seabed anchors and moved one end of Aquarius by .
In 2017,
Hurricane Irma
Hurricane Irma was an extremely powerful and devastating tropical cyclone that was the first Category 5 hurricane to strike the Leeward Islands on record, followed by Hurricane Maria, Maria two weeks later. At the time, it was considered ...
ripped the habitat's life support buoy from its moorings and blew it away to the Lignum Vitae Channel, as well as damaging the underwater living quarters and wet porch area. , no scientists or staff members had been injured at Aquarius due to storms.
Since 2001,
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
has used Aquarius for its
NEEMO (NASA Extreme Environment Mission Operations)
analog missions, sending groups of
astronauts
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a List of human spaceflight programs, human spaceflight program to serve as a commander or crew member of a spa ...
to simulate
human spaceflight
Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be ...
space exploration missions. Much like space, the undersea world is a hostile, alien place for humans to live. NEEMO crew members experience some of the same challenges there that they would on a distant asteroid, planet or moon. During NEEMO missions in Aquarius, the aquanauts are able to simulate living on a spacecraft and test spacewalk techniques for future space missions. The underwater condition has the additional benefit of allowing NASA to "weight" the aquanauts to simulate different gravity environments.
A diver named
Dewey Smith died during a dive from Aquarius in May 2009.
A subsequent investigation determined that Smith's death was caused by a combination of factors, including the failure of the electronic functions of his
Inspiration closed circuit rebreather due to hydrodynamic forces from a hydraulic impact hammer being used nearby.
Due to budget cuts, NOAA ceased funding Aquarius after September 2012, with no further missions scheduled after a July 2012 mission that included pioneering female diver
Sylvia Earle in its aquanaut crew. The University of North Carolina Wilmington was also unable to provide funding to continue operations. The Aquarius Foundation was set up in an attempt to keep Aquarius functioning.
In a two-week series, the daily cartoon strip ''
Sherman's Lagoon'' featured the potential closing of the Aquarius facility in the week starting September 10, 2012, and continued with a cameo appearance of Earle in the week starting September 17, 2012, to discuss the importance of Aquarius.
In January 2013, a proposal to keep Aquarius running under Florida International University administration was accepted.
From June 1 to July 2, 2014,
Fabien Cousteau and his crew spent
31 days living and working in Aquarius in tribute to
Jacques Cousteau
Jacques-Yves Cousteau, (, also , ; 11 June 191025 June 1997) was a French naval officer, oceanographer, filmmaker and author. He co-invented the first successful open-circuit self-contained underwater breathing apparatus (SCUBA), called the ...
's 30-day underwater expedition in 1963. Cousteau estimated the team collected the equivalent of two years' worth of surface diving data during the mission, enough for ten scientific papers.
References
General references
* ENN.
Age of Aquarius: Undersea lab immersed in coral reef research', 2000.
* NOAA.
', 2004
* Plain, C.
', 2004
External links
*
{{authority control
National Oceanic and Atmospheric Administration
Oceanography
Underwater habitats
University of North Carolina at Wilmington
1993 establishments in Florida
Florida International University
Florida Keys
Buildings and structures in Monroe County, Florida