Ocean Relief
Solid Surface Distribution of the Earth
Fig: 1 Features of earth’s solid surface shown as percentages of the planet’s total surface.
List of Deep-Sea Exploration Instruments
➢ Remotely Operated Vehicles (ROVs)
➢ Autonomous Underwater Vehicles (AUVs)
➢ Human-Occupied Vehicles (HOVs)
➢ Sound Detection and Ranging (SONAR)
➢ Light Detection and Ranging (LIDAR)
➢ CTD (Conductivity, Temperature, and Depth) Sensors
➢ Sediment Corers
➢ Magnetometers
➢ Environmental DNA (eDNA) Samplers
➢ Remote Sensing and GIS
➢ Precision depth Recorder (PDR)
➢ MARC (Sea mapping & Remote Characterization)
➢ GLORIA (Geological Long Range Inclined Acoustical Instrument)
Deep Sea Exploration
Only 5% of the ocean has been explored and more than 80% of the ocean remains unexplored. Deep-
sea exploration is the investigation of physical, chemical, and biological conditions on the ocean waters
and sea bed beyond the continental shelf, for scientific or commercial purposes. Deep-sea exploration
is an aspect of underwater exploration and is considered a relatively recent human activity compared to
the other areas of geophysical research, as the deeper depths of the sea have been investigated only
during comparatively recent years. The ocean depths still remain a largely unexplored part of the Earth,
and form a relatively undiscovered domain.
1
, Deep Sea Exploration Timeline
Year Event
1521 Ferdinand Magellan attempted to measure the depth of the Pacific Ocean with a
weighted line.
1810–1827 Antoine Risso described and named deep-sea species found between 600-1,000 m
in the Gulf of Genoa.
1818 Sir John Ross discovered deep-sea life at 2,000 m depth, catching jellyfish and
worms.
1843 Edward Forbes claimed life decreases with depth, stating no life exists below 550
m (Abyssus Theory).
1850 Michael Sars refuted the Abyssus Theory by finding diverse deep-sea life at 800 m
near Lofoten.
1872–1876 HMS Challenger expedition, led by Charles Wyville Thomson, conducted the first
systematic deep-sea exploration.
1890–1898 Austrian-Hungarian expedition led by Franz Steindachner explored deep seas in
the eastern Mediterranean.
1898–1899 German expedition on ship Valdivia, led by Carl Chun, found new species at depths
greater than 4,000 m.
1930 William Beebe and Otis Barton became the first humans to reach 435 m depth in
the Bathysphere.
1934 Bathysphere reached a depth of 923 m.
1947–1948 Swedish Albatross expedition collected 20-m sediment cores and trawled at depths
of 7,600–7,900 m.
1948 Otis Barton set a new record, diving to 1,370 m in the Bathysphere.
1960 Jacques Piccard and Don Walsh reached 10,740 m in the Challenger Deep aboard
the vessel Trieste.
2012 James Cameron piloted Deepsea Challenger to the bottom of Challenger Deep on
a solo mission.
2018 Victor Vescovo piloted DSV Limiting Factor to 8,375 m in the Puerto Rico Trench.
2019 DSV Limiting Factor explored various deep-sea locations, including the South
Sandwich, Sunda, and Tonga Trenches.
2020 Kathryn Sullivan and Vanessa O'Brien became the first women to reach the bottom
of Challenger Deep at 10,925 m.
Table: 1 Deep Sea Exploration Timeline
Terms
➢ Bathymetry: measures depth
➢ Hypsometry: measures elevation
Continental Margins
➢ It represents the boundaries of lands towards oceans. They are two types:
❖ Active Continental Margins: Faulting & Folding into the formation of folded mountains,
volcanicity, seismic activities etc.
❖ Passive Continental Margins: It represents no major tectonic activities.
Major Relief Features
Continental Shelf
➢ Gently sloping area.
2
Solid Surface Distribution of the Earth
Fig: 1 Features of earth’s solid surface shown as percentages of the planet’s total surface.
List of Deep-Sea Exploration Instruments
➢ Remotely Operated Vehicles (ROVs)
➢ Autonomous Underwater Vehicles (AUVs)
➢ Human-Occupied Vehicles (HOVs)
➢ Sound Detection and Ranging (SONAR)
➢ Light Detection and Ranging (LIDAR)
➢ CTD (Conductivity, Temperature, and Depth) Sensors
➢ Sediment Corers
➢ Magnetometers
➢ Environmental DNA (eDNA) Samplers
➢ Remote Sensing and GIS
➢ Precision depth Recorder (PDR)
➢ MARC (Sea mapping & Remote Characterization)
➢ GLORIA (Geological Long Range Inclined Acoustical Instrument)
Deep Sea Exploration
Only 5% of the ocean has been explored and more than 80% of the ocean remains unexplored. Deep-
sea exploration is the investigation of physical, chemical, and biological conditions on the ocean waters
and sea bed beyond the continental shelf, for scientific or commercial purposes. Deep-sea exploration
is an aspect of underwater exploration and is considered a relatively recent human activity compared to
the other areas of geophysical research, as the deeper depths of the sea have been investigated only
during comparatively recent years. The ocean depths still remain a largely unexplored part of the Earth,
and form a relatively undiscovered domain.
1
, Deep Sea Exploration Timeline
Year Event
1521 Ferdinand Magellan attempted to measure the depth of the Pacific Ocean with a
weighted line.
1810–1827 Antoine Risso described and named deep-sea species found between 600-1,000 m
in the Gulf of Genoa.
1818 Sir John Ross discovered deep-sea life at 2,000 m depth, catching jellyfish and
worms.
1843 Edward Forbes claimed life decreases with depth, stating no life exists below 550
m (Abyssus Theory).
1850 Michael Sars refuted the Abyssus Theory by finding diverse deep-sea life at 800 m
near Lofoten.
1872–1876 HMS Challenger expedition, led by Charles Wyville Thomson, conducted the first
systematic deep-sea exploration.
1890–1898 Austrian-Hungarian expedition led by Franz Steindachner explored deep seas in
the eastern Mediterranean.
1898–1899 German expedition on ship Valdivia, led by Carl Chun, found new species at depths
greater than 4,000 m.
1930 William Beebe and Otis Barton became the first humans to reach 435 m depth in
the Bathysphere.
1934 Bathysphere reached a depth of 923 m.
1947–1948 Swedish Albatross expedition collected 20-m sediment cores and trawled at depths
of 7,600–7,900 m.
1948 Otis Barton set a new record, diving to 1,370 m in the Bathysphere.
1960 Jacques Piccard and Don Walsh reached 10,740 m in the Challenger Deep aboard
the vessel Trieste.
2012 James Cameron piloted Deepsea Challenger to the bottom of Challenger Deep on
a solo mission.
2018 Victor Vescovo piloted DSV Limiting Factor to 8,375 m in the Puerto Rico Trench.
2019 DSV Limiting Factor explored various deep-sea locations, including the South
Sandwich, Sunda, and Tonga Trenches.
2020 Kathryn Sullivan and Vanessa O'Brien became the first women to reach the bottom
of Challenger Deep at 10,925 m.
Table: 1 Deep Sea Exploration Timeline
Terms
➢ Bathymetry: measures depth
➢ Hypsometry: measures elevation
Continental Margins
➢ It represents the boundaries of lands towards oceans. They are two types:
❖ Active Continental Margins: Faulting & Folding into the formation of folded mountains,
volcanicity, seismic activities etc.
❖ Passive Continental Margins: It represents no major tectonic activities.
Major Relief Features
Continental Shelf
➢ Gently sloping area.
2
