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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.
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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 barrierisland 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.
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.
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.
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.
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.
A submarine canyon is a steep-sided valley on the sea floor of the continental slope.
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.
The continental rise is the gently sloping accumulation of sediments deposited by a turbidity current at the foot of a continental margin.
The ocean basins make up 60% of the Earth’s surface. • 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.
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.
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.
