Chapter 16: The Marine Environment

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Chapter 16 The Marine Environment
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1. A beach is the accumulation of sediment along
the shore of a lake or ocean.
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2. Waves are constantly eroding, transporting,
and depositing sediment resulting in many
shoreline features.
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3. A longshore current moves parallel to the
shoreline. It moves along the shore.
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4. A barrier island is a long, narrow sandbar
parallel to, but separated from, the mainland.
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5. North Carolina is a state that has many
barrier islands. Texas also has some.
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6. An inlet is a division between barrier
islands.
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Inlet Inlet Inlet
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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.
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9. An estuary is the area where a river or stream
enters the ocean. Causes brackish water- a
combination of fresh and salt water.
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• 10. Estuaries are important because they allow
  many types of shellfish and other marine life to
  mature in that habitat.

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11. Shorelines can be eroded at rapid rates due
to storms. Why might people worry about this?
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• 12. How can the shore line be eroded?

13. People spend lots of money trying to prevent
this erosion.

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14. A groin is a barrier build perpendicular to
the shore to trap sand. Why might this cause
problems?
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15. A jetty is a groin built to protect the
entrance to a harbor.
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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
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17. Beach nourishment is the addition of large
quantities of sand to a beach. Very expensive.
Only lasts a few years.
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18. Who should pay for beach nourishment? 19.
These are all temporary solutions. What might be
better solutions?
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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.

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1. The deepest place in the ocean is the
Marianas Trench in the Pacific Ocean.
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1. 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.

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• 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

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4. The Atlantic Ocean has a wider continental
shelf, averaging hundreds of km.
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1. 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.

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• A submarine canyon is a steep-sided valley on
  the sea floor of the continental slope.

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• 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.

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1. The continental rise is the gently sloping
   accumulation of sediments deposited by a
   turbidity current at the foot of a continental
   margin.

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1. The ocean basins make up 60 of the Earths
   surface.
2. 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

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11. A trench is a long depression in the ocean
floor at the junction of two plates where
subduction occurs.
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• 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.

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Mid Ocean Ridge
13. A rift valley is the middle part of the mid
ocean ridge.
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• 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.

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A hot-water, deep-sea vent that has the energy
and nutrients needed for the beginning of life.
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15. A seamount is a basaltic, submerged volcano
on the seafloor that is more than 1 km high.
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Index SMNT-131S-1753W Classification Very Small B3 Seamount
Location 13º 04.86' S175º 15.85' W ElongationIrregularity 2.09 0.041.27 0.03
Plate Age Oceanic Province Abyssal Plain
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.
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16. A guyot is a flat-topped seamount.
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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.
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• Ooze Shells and hard parts of marine organisms
  that accumulate on the ocean floor and create
  sediment.
• Small
• Most are calcium carbonate or silica

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• 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.

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Manganese Nodules