Transcript Introduction – Chapter 1

Introduction to Oceanography
Dr. Marianne E. McNamara
First, An icebreaker…
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Your major
Your year/Part time or full time
Your plans
Your objectives
Your interests
What is oceanography?
• Oceanography is the study of the ocean
– An interdisciplinary science:
• Geology
• Geography
• Chemistry
• Physics
• Biology
• Astronomy
What is oceanography?
• Oceanography consists of several specialized
disciplines
– Marine Biology (Biological oceanography)
– Chemical Oceanography
– Geological Oceanography
– Physical Oceanography
– Marine Engineering
– Marine Ecology
– Marine Management
Oceanography ≠ Dolphins!
Chemical
Oceanography
Physical
Oceanography
Biological
Oceanography
Geological
Oceanography
…but it is one way to unleash your
inner dolphin hugger…
Got Ocean?
• The ocean covers 71% of the Earth’s surface
• Accounts for >97% of the Earth’s water!
• The average depth of the ocean is 3,800
meters (12,500 feet) and at its deepest depth
is 7,000 ft greater than the highest elevation
on land (Mt. Everest 29,000 ft; Mariana Trench
36,163 ft)
• The average temperature of the ocean is only
3.9 ̊C (39 ̊F)
Oceanography
• For our convenience, the oceans are
separated into 5 named ocean basins (and
many smaller seas), but they all constitute one
world ocean; one great intermixing mass of
saline (salty) water
• All oceans are, in fact, interconnected with
one another
One World Ocean
• Pacific Ocean
(the largest)
• Atlantic Ocean
• Indian Ocean
• Arctic Ocean
• Southern Ocean
One World Ocean
Arctic
Ocean
Pacific Ocean
Atlantic
Ocean
Indian
Ocean
Southern Ocean
http://www.gebco.net/data_and_products/gebco_world_map/images/gda_world_map_large.jpg
The Ocean’s Origins
• The Earth is believed to be 4.6 billion years old
• During the Earth’s formation, heavy (dense)
metals such as iron and nickel gravitated
towards the hot center in a molten state
• At the same time,
lighter elements
such as aluminum
and silicon rose
towards the
surface, forming
the Earth’s crust
The Ocean’s Origins
• Crust is made
up of
different
rock types,
and so is
thinner
and thicker
in places
• Thick = land; thin = ocean!
The Ocean’s Origins
• Eventually, the young Earth cooled enough
such that water vapor condensed and
collected in the ocean basins
• As water collected,
it dissolved minerals
within the rocks
• After 20 million
years of rain, the
oceans were born!
Why study oceanography?
• ~80% of all Americans live within 1 hour of an
ocean or Great Lake
• 100% of all Long Islanders live within 1 hour of
the Atlantic Ocean
• 50% of the world’s
population live on
a coastline
Why study oceanography?
We live on Long ISLAND; The ocean is our backyard!!!
Why study oceanography?
• Our Earth is a
BLUE planet
• Why blue?
Why study oceanography?
• More than half of the oxygen we breath is
produced in the ocean!
http://www.nasa.gov/centers/goddard/images/content/95573main_plankton_satellite.jpg
Why study oceanography?
• Oceans moderate the Earth’s climate
Why study oceanography?
"Old Inlet" breach in Fire Island caused by Sandy. Photo by National Park Service
Why study oceanography?
• Because it’s the stuff of legends
(and nightmares…)
Why study oceanography?
• Because it’s the stuff of legends
(and inspirations)
Why study oceanography?
• So you can understand this on a deeper level
http://www.youtube.com/watch?v=hwlZUKv57B4
Why study oceanography?
Why study oceanography?
Why study oceanography?
Oceanography
• Oceanography deals with understanding the
complex relationships between physics,
geology, chemistry and biology
• Oceanography must
consider the
relationships
between land and
sea, and within the
ocean itself
The History of Oceanography
• Explorers and scientists have been studying
the oceans for millennia and centuries,
respectively
1769 chart of the Gulf Stream by Benjamin Franklin
History of Oceanography
• In fact, the units of latitude and longitude
were developed by Alexandrian (Greek)
scholars ~200 years BCE
• Latitude and longitude are systems of
imaginary lines
dividing the surface
of the Earth
• Essential for
navigation
Latitude and Longitude
• Latitude lines run parallel to the equator
• Longitude lines run from pole to pole
The History of Oceanography
• The most famous and extensive study of the
ocean was conducted by the British in the 19th
century
– The HMS Challenger sailed the seas between
1872-1876
– Motivated by economic and military interests
– Explored nearly every all parts of the world’s
ocean
• Seawater samples, biological samples, depths,
sediment composition
The Challenger expedition
• Voyage track from 1872-1876; remains the
longest continuous oceanographic survey
History of Oceanography
• The Challenger expedition successfully
disproved the Azoic hypothesis – the belief
that no life existed below 550 meters
• Collection of life in the depths launched the
science of marine biology!
Oceanography: The Final Frontier?