Pacific Ocean above Juan de Fuca Ridge.

1818
Sir John Ross lowers a line more than a mile into the North Atlantic and hauls up worms and a large sea star.

1843
Edward Forbes proposes that no substantial life can exist below three hundred fathoms.

1858
The first transatlantic telegraph cable comes to life, its laying preceded by deep seabed surveys.

1859
Darwin's Origin of Species implies that the deep is a sanctuary for living fossils.

1864
Norwegians haul up from the deep a sea lily, a living fossil previously found only in rocks 120 million years old.

1870
Jules Verne's Twenty Thousand Leagues Under the Sea depicts no life in the ocean's deepest regions.

1872-76
British ship Challenger sails the globe while lowering dredges and other gear into the deep, finding long mountain chains, puzzling nodules, and hundreds of animals previously unknown to science.

 

The 'Pompeii' tubeworm, Alvinella pompejana.

1892
Prince Albert of Monaco starts to probe the sea's dark midwaters, discovering new kinds of eels, fish, and squid.

1920
Alexander Behm sails the North Sea and bounces sound waves off its bottom, advancing a new method of depth measurement known as echo sounding.

1925
Fritz Haber launches the German Meteor expedition in a bid to extract gold from seawater.

1934
William Beebe and Otis Barton descend in a tethered sphere to a depth of a half mile, where they glimpse a previously unseen world of living lights and bizarre fish.

1938
Fishermen off South Africa pull up an ungainly five-foot fish identified as a coelacanth, a living fossil thought extinct since the days of the dinosaurs.

 

Coelacanth, the 'fossil fish'.

1948
Auguste Piccard dives in his bathyscaph, the first untethered craft that carried people into the deep.

1950-52
Danish ship Galathea lowers dredges into the sea's deepest trenches and hauls up swarms of invertebrates.

1951
British ship Challenger II bounces sound off the bottom, and near Guam finds what appears to be the sea's deepest chasm, its lowest point nearly seven miles down, subsequently named the Challenger Deep.

1952
Marie Tharp, studying echo soundings, discovers that the Mid-Atlantic Ridge conceals a long rift valley, which turns out to be part of a hidden volcanic rent that girds the global deep.

 

Vent in the ocean floor.

1953
Auguste Piccard and his son Jacques enter Trieste, an improved bathyscaph, and dive to a depth of nearly two miles.

1958
American Navy buys Trieste and begins to strengthen its steel personnel sphere.

1960
Jacques Piccard and Don Walsh dive in Trieste to bottom of Challenger Deep, seven miles down.

1961
American ship off Mexico lowers a pipe through more than two miles of water and drills into the rocky seabed, a first that advances the fields of deep geology and mining.

Robert Dietz, studying echo soundings, proposes that the seabed's mountainous rifts are invisible scars where molten rock from the Earth's interior wells up periodically and spreads laterally to form new ocean crust, a process he calls seafloor spreading.

 

Lava mound on the East Pacific Rise.

1963
Thresher, America's most advanced submarine, sinks in waters a mile and a half deep with the loss of 129 men.

Trieste finds the shattered hulk of Thresher on the bottom after five months of searching.

1964
American Navy founds the Deep Submergence Systems Project to develop new gear that can better probe the deep sea's darkness. Navy launches submersible Alvin, the first piloted craft able to roam the deep with relative ease.

 

The submersible Alvin on duty.

1965
Navy tests its first underwater robot.

Navy develops Halibut, a submarine that can lower miles of cables bearing lights, cameras, and other gear to spy on enemy armaments and materiel lost on the bottom of the sea.

1966
Alvin and Navy robot probe the deep Mediterranean and retrieve a lost American hydrogen bomb.

Halibut spies on Soviet warheads abandoned to the deep.

1967
Geologists, after fierce debate, agree that seafloor spreading involves a dozen or so huge plates that form the Earth's crust and move slowly over time, rearranging the land.

 

An undescribed vent anemone with three-foot-long tentacles.

1968
Soviet submarine sinks in the deep Pacific, littering seabed with secret code books and nuclear warheads.

In stealth, Halibut examines the lost Soviet sub.

American Navy sub Scorpion sinks in the Atlantic, killing 99 men and surrendering to the depths two torpedoes tipped with nuclear arms.

1969
Trieste II, a new Navy bathyscaph, probes the Scorpion's wreckage more than two miles down and recovers the sub's sextant.

1971
Navy launches first of two piloted craft that hitch rides atop submarines and dive deep for rescues and espionage.

 

A bloom of tubeworms.

1973
Navy begins to design a type of tetherless robot, eventually known as the Advanced Unmanned Search System, for wide hunts of gear lost at depths up to nearly four miles.

1974
Disguised as a seabed miner, American ship Glomar Explorer lowers a giant claw to grab a Soviet sub lost on the Pacific floor.

United Nations Law of the Sea conference proposes to tax seabed miners as a way of enriching poor nations.

French-American team dives to Mid-Atlantic Ridge and unexpectedly finds its rift valley paved with lava.

 

Mussels and tubeworms share a vent site.

1977
American team dives in Alvin to a volcanic rift in the Pacific and discovers warm springs teeming with undescribed species of life, an ecosystem new to science that includes tubeworms, snakelike creatures standing upright in long tubes.

1979
American team exploring Gulf of California with Alvin finds mineral chimneys that blow clouds of black smoke and discharge water hot enough to melt lead.

1980
Scientists propose that the seabed's hot springs are the birthplace of all life on Earth.

 

Venting black smoker chimney.

1981
Ronald Reagan becomes President and begins an arms buildup, including new classes of deep craft and new kinds of deep espionage.

1982
Volcanic seamounts in Pacific are found to be covered with rare metals, including cobalt. United Nations Law of the Sea Treaty is finished and opened for ratification, saying deep minerals belong to the world's people.

1983
Reagan proclaims Exclusive Economic Zone around the United States, effectively doubling the nation's size and fueling a burst of exploration in deep waters.

1984
Robert Ballard tows tethered Navy craft Argo over the Thresher, scanning the lost sub's corroding wreckage with an array of video cameras.

American researchers diving off Florida in Alvin discover life swarming in cold springs, another new kind of deep ecosystem.

 

Swarming life at a cold seep on the Louisiana Slope.

Mikhail Gorbachev emerges as Soviet leader, starting conciliatory East-West policy.

1985
Ballard lowers Navy craft Argo and discovers, more than two miles down, the Titanic, broken in two, many of its fixtures and artifacts scattered on the icy seabed.

Graham Hawkes's Deep Rover submersible reveals a riot of midwater life in the depths of Monterey Canyon, helping inspire billionaire David Packard to fund deep explorations.

1986
New Navy robot Jason Junior probes the interior of the Titanic, and in secret missions explores the twisted wreckage of two sunken American submarines, Thresher and Scorpion.

 

The hydrothermal vent known as 'Inferno.'

1987
American firm hires the French Nautile submersible to begin Titanic's salvage, hauling up thousands of items, including children's marbles and a lady's wristwatch.

First East-West treaty is signed that reduces nuclear arms.

1988
Treasure hunters searching off South Carolina more than a mile down find the remains of the Central America, a wooden ship that sank in 1857, heavy with tons of California gold. Ballard tows Navy craft Argo over Mediterranean deep and discovers a graveyard of ancient ships, including a fourth-century Roman craft.

1989
Ballard lowers Argo nearly three miles down in the Atlantic and finds German battleship Bismarck, a mass of deteriorating guns and fading swastikas.

Jason, Ballard's top robot for the Navy, debuts and recovers from the deep Mediterranean dozens of artifacts from lost Roman ships.

 

Crabs scavenge on giant tubeworms.

Berlin Wall crumbles.

1990
Navy begins giving civilian researchers wide access to NR-1, a deep-diving nuclear submarine with lights, windows, and wheels.

Japan finishes Shinkai 6500, the world's deepest-diving piloted craft.

Russians in Mir submersibles probe Monterey Canyon, one of the first in a wave of post-cold-war dives for foreign customers.

1991
American Navy agrees to share with civilian scientists a fleet of deep exploratory craft, including robots and submersibles.

 

Mir submersible investigates the seafloor.

Mir submersibles dive more than two miles down and film Titianic wreckage for Canadian IMAX movie.

Soviet ship Yuzhmorgeologiya, which once spied on the submarines of the United States Navy, is hired by American government to do studies of deep ecology.

Soviet Union ceases to exist.

1992
Scientists, after a large seabed survey, conclude that the deep may hold ten million species of life, far more than are known on land.

 

A deep-sea anemone crowns a lava pillar.

Ballard lowers Navy submersible Sea Cliff and Navy robot Scorpio to examine fourteen ships lost during World War Two at the battle of Guadalcanal.

CIA director Robert Gates tells Russian President Boris Yeltsin that Glomar Explorer recovered remains of six Soviet sailors, who were subsequently buried at sea.

American Navy adopts a new strategy in which fighting forces target shallow waters and regional conflicts, reducing the need for deep expertise.

Businessmen hire an American Navy contractor to dive on Titanic for commercial salvage.

1993
Two American companies unveil laser cameras, formerly secret Navy tools for seeing long distances in the deep.

 

Map of the Juan de Fuca Ridge.

Federal scientists listen to Navy deep microphones and hear a deep volcanic outburst on the Pacific's Juan de Fuca Ridge, prompting a number of expeditions to study how heat on the dark seabed can beget a jungle of life.

Japan begins testing Kaiko, the world's deepest-diving robot.

French submersible Nautile dives on Titanic to recover artifacts.

Ballard lowers Navy Jason robot in Celtic Sea to probe the deteriorating remains of Lusitania, torpedoed by Germany in 1915.

1994
American Navy agrees to share its attack submarines with civilian scientists for arctic studies.

Navy turns over the Advanced Unmanned Search System, an early tetherless robot, to private industry.

Shinkai 6500 sets an Atlantic depth record for a piloted vehicle, studying deep geology.

 

Octopus clambers across the sea bottom.

Russians in Mir submersibles carry British scientists down to Mid-Atlantic Ridge to study a huge volcanic mound laced with gold.

Nautile dives on Titanic to recover artifacts.

United Nations Convention on the Law of the Sea goes into force.

1995
Kaiko dives to bottom of Challenger Deep, finding the icy darkness alive with small animals.

Paul Tidwell arms himself with naval spinoffs and finds in Atlantic waters more than three miles down the lost Japanese submarine I-52, which sank in 1944 heavy with tons of gold.

 

A tubeworm community.

Ballard dives in Navy's NR-1 to map a field of deep Mediterranean wrecks, some more than 2,000 years old.

Mir submersibles film Titanic for a Hollywood movie.

American Navy releases seafloor gravity data, which civilian oceanographers turn into the first good public map of the global seabed.

Civilians start broadcasting deep sounds across the Pacific and listening with Navy microphones for changes in travel time, seeking to measure global warming.

1996
Federal scientists listening to Navy microphones hear fury on the Gorda Ridge, prompting new studies of seabed volcanism.

 

Billowing 'smoke' from a deep-sea vent.

The robot Jason, one of the Navy's top deep projects of the 1980s, makes its debut for a Federal scientific group, its first expedition probing hot vents on the Mid-Atlantic Ridge.

Navy widens access to its deep microphones, prompting the development of private acoustic observatories meant to listen for volcanic eruptions and whale songs.

The advanced robot Tiburon debuts at Packard's institute, ready to explore down to a depth of four kilometers, or two and a half miles.

Nautile dives on the Titanic to film the shattered hulk and recover artifacts, including a large section of the liner's hull.

 

'Deep Flight' on a mission.

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