Transcript GEOSC 40 - Penn State York

GEOSC 40
“The Sea
Around Us”
Rachel Carson, 1951.
Book on environmental
awareness. Her writing
reflects a passion and
knowledge of the marine
environment. She
recognized research
issues and foresaw
environmental problems
that are critical today.
Extra Credit Option
bookreport / essay
Define Oceanography
Study of the ocean and its basins; a multidisciplinary science
involving aspects of physics, chemistry, geology and biology.
Why are Oceans important to Man?
Transportation
Water Supply
Defense
Power Supply
Recreation
Biomedicines
Archeology
Global Climate
Fisheries
Natural Hazards
Minerals
Pollutants
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Pfiesteria piscicida toxins
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Hydrologic Cycle
Primary forces involved
are solar radiation &
gravity!
Solar energy drives
evaporation and
transpiration of land
plants.
Gravity drives
precipitation, infiltration
and flow of streams and
groundwater to oceans.
Atmospheric net
transport is sea to land.
Define Oceanography
Study of the ocean and its basins; a multidisciplinary science
involving aspects of physics, chemistry, geology and biology.
Earth’s Ocean
covers 71% of its
surface area.
60.7:39.3
sea:land
80.9:19.1
sea:land
Where did Earth’s water originate? What is the origin of Earth?
Origin of Earth and Life
• 15 billion Years Ago (15
Ga) the Big Bang to form
the Universe.
• Simple atoms began to
form during the following
millions of years.
• After billions of years
clusters of galaxies
formed.
• Spheres of hot gasses
(nebula) within galaxies
ultimately formed
individual solar systems.
Coma Berenices Galaxy 62 MLY away
Solar Nebula
Hubble Telescope image
Solar System Formation:
Hot gasses of solar nebula begin the cool (5 Ga = 5 billion years ago)
for our Sun.
Spinning sphere takes on a disk shape and heavy atoms coalesce
into the center, forming a protosun.
Within the next 100 million years the accretion of atoms is so intense
that nuclear fusion reaction begin, which form heavier elements, heat
and light energy.
One day the Sun, like other past stars, will explode, or supernova.
Formation of Earth:
4.7 Ga small asteroid, dust and gases in our
solar system began to condense into
planets.
Heavier materials were attracted closer to
the sun than light gaseous materials. The
plants close to the sun today (Mercury,
Venus, Earth and Mar) are called terrestrial
planets.
Jovian planets (Jupiter, Saturn, Uranus,
Neptune, Pluto) are farther from the sun and
made of the lighter gases compounds.
Materials that first aggregated to form the
Earth, underwent the process called density
stratification. Heavier elements went to the
center and lighter stayed to the surface to
form the cooler solid crust.
The Moon
• Where did our moon come
from?
– A collision >4.5 billion years
ago by either a
– Huge asteroid, or
– Mars size planet.
– The material ejected from Earth
stayed in its gravitational field
and aggregated.
• Why is the Moon important to
life on Earth?
– Tides
– Gravity stabilizes the wobble of
Earth’s axis relative to the sun,
– “If we had no Moon”.
Where did Earth’s water come from?
• 1) Outgassing of water
from the Earth’s
interior by volcanic
activity. This alone
could have filled the
oceans in 0.5 billion
years.
• 2) Bombardment by
icy comets.
What may have
been the Origin of
Life on Earth?
Early Earth did not contain
oxygen in its atmosphere, we
refer the early atmosphere as
reducing as opposed to
oxidizing in its chemical nature.
One theory in the scientific
community is that organic
(carbon containing)
compounds became more
complex and organized until
the first cells evolved from this
“organic soup”. This is called
the “Biosynthesis Theory”.
Stanley Miller, 1953 apparatus
A second theory takes the
biosynthesis idea further, and
suggests that the processes
needed to have protection
from the violent (high UV) and
cool surface, conditions.
Deep-sea geothermal vents
are proposed to be the
location where life began.
The third theory, Panspermia,
is that Earth may simply have
been inoculated with life from
an extraterrestrial source.
There is evidence of
meteorites with “life signs” and
there are other planets or
moons with water.
Compromise theories too!
Surface of Mars, once believed
to have water at its surface,
now only underground.
Surface of Europa (moon of Jupiter)
Fossilized microbes;
3.8 Ga in oldest rocks.
Geological History
Consider Earth as a 46 year old person:
Birth = first microbes (Prokaryotes) 3.6 Ga
21 y = first oxygen producing microbes 2 Ga
28 y = first advanced cells (Eukaryotes)
36 y = first multi-celled animals
Last 25 days = first humans
Last minute = industrial revolution 1850s
Last second was 2.5 years ago.