Transcript Ch. 16 PowerPoint

Chapter 16: The Marine Environment
1. A beach is the accumulation of
sediment along the shore of a
lake or ocean.
2. Waves are constantly eroding,
transporting, and depositing sediment
resulting in many shoreline features.
3. A longshore current moves parallel to
the shoreline. It moves along the
shore.
4. A barrier island is a long, narrow
sandbar parallel to, but separated from,
the mainland.
5. North Carolina
is a state that
has many
barrier islands.
Texas also has
some.
6. An inlet is a division
between barrier
islands.
Inlet
Inlet
Inlet
7. A sound is a body of water that
separates barrier islands from the
mainland.
8. Examples
in N.C. are
the Pamlico
and
Albermarle
Sound.
9. An estuary is the area where a river or
stream enters the ocean. Causes
brackish water- a combination of fresh
and salt water.
10. Estuaries are important because they
allow many types of shellfish and other
marine life to mature in that habitat.
11. Shorelines can be eroded at rapid
rates due to storms. Why might people
worry about this?
12. How can the shore line be eroded?
13. People
spend lots of
money trying
to prevent
this erosion.
14. A groin is a barrier build perpendicular
to the shore to trap sand. Why might this
cause problems?
15. A jetty is a groin built to protect the
entrance to a harbor.
16. A seawall is parallel to the shore and
protects the coast and property from the
force of waves.
Galveston, TX
Right Before
Hurricane Rita
Hits the Coast
17. Beach nourishment is the addition of
large quantities of sand to a beach. Very
expensive. Only lasts a few years.
18. Who should pay for beach
nourishment?
19. These are all temporary solutions.
What might be better solutions?
16.2 The Seafloor
• We are able to study the ocean floor with
the invention of new technologies;
SONAR, satellites, ROVs and so on.
• SONAR is a system using transmitted and
reflected underwater sound waves to
detect and locate submerged objects or
measure the distance to the floor of a body
of water.
• SONAR was first used in the 1920s.
1. The deepest place in the ocean is the
Marianas Trench in the Pacific Ocean.
2. The continental margin is the
submerged part of a continent and
shallowest part of the ocean that
consists of the continental shelf,
continental slope, and continental rise.
3.The continental shelf is the shallowest
part of a continental margin.
• Average depth of 130 m
• Average width of 60 km
• Extends into the ocean from the shore
and provides a nutrient-rich home to
large numbers of fish
4. The Atlantic Ocean has a wider
continental shelf, averaging hundreds of
km.
5.The continental slope is the sloping
oceanic region found beyond the
continental shelf that generally marks
the edge of the continental crust and
may be cut by submarine canyons.
6. A submarine canyon is a steep-sided
valley on the sea floor of the continental
slope.
7.Turbidity currents are rapidly flowing
ocean currents that can cut deep-sea
canyons in continental slopes and
deposit the sediments in the form of a
continental
rise.
8.The continental rise is the gently sloping
accumulation of sediments deposited by
a turbidity current at the foot of a
continental margin.
9. The ocean basins make up 60% of the
Earth’s surface.
10.An abyssal plain is a smooth, flat part
of the seafloor covered with muddy
sediments and sedimentary rocks that
extends seaward from the continental
margin
11. A trench is a long depression in the
ocean floor at the junction of two plates
where subduction occurs.
12. The mid ocean ridge is a chain of
underwater mountains that run through
the ocean basins.
• They are the site of volcanoes producing
new ocean crust.
• Have a total length of over 65,000 km
• Contain countless active and extinct
volcanoes.
Mid Ocean Ridge
13. A rift valley is the middle part of the
mid ocean ridge.
14. A hydrothermal vent is a hole in the
seafloor through which fluid heated by
magma erupts. They are an important
feature because they are the source of
warm water deep in the ocean and
support their own unique habitat.
A hot-water, deep-sea vent that has the
energy and nutrients needed for the
beginning of life.
15. A seamount is a basaltic, submerged
volcano on the seafloor that is more than 1
km high.
Index
SMNT-131S1753W
Classification
Very Small B3
Seamount
Location
13º 04.86' S
175º 15.85' W
Elongation
Irregularity
2.09 ± 0.04
1.27 ± 0.03
Oceanic
Province
Abyssal Plain
Plate Age
Region
Samoan Hotspot
Trail
Alternative
Names
Plate
Pacific Plate
Age
Tectonic
Setting
Hotspot Trail
Seamount
Top
1585 m
Volume
356 km3
Ocean
Bottom
3955 m
Volcanic
Activity
Extinct
Fa'aliga Seamount is located at 13? 4.8' S, 175? 15.8' W and is part
of the Samoa Hotspot Trail on the Pacific Plate. It is 2370 m in
height with the top at -1585 m and the ocean bottom at -3955 m. It
is very small with a volume of 356 km3. The seamount is
moderately elongated in a southeast, northwest direction with an
azimuth of approximately 115?. The edges of the seamount are
slightly irregular.
16. A guyot is a flat-topped seamount.
17. The bottom of the seafloor is
covered with marine sediments.
They are composed of sediments
from the land and remnants of dead
sea life. Manganese nodules can
form directly from minerals in ocean
water.
Ooze: Shells and hard parts of marine
organisms that accumulate on the ocean
floor and create sediment.
•Small
•Most are calcium carbonate or silica
Manganese Nodules
Oxides of manganese, iron, copper, and
valuable metals that precipitated directly
from seawater.
•Growth rates very slow
•Resemble potatoes
•Cover huge areas
of the seafloor.
Manganese Nodules