- Longshore transport can change direction depending on which direction the waves approach the beach. - Longshore transport moves sediment upcoast or downcoast along the beach. - Longshore transport moves sediment in a zigzag path Southern California beaches in winter typically are narrow and rocky.
Longshore drift can be very destructive to manmade structures. Click the image to view a slideshow and learn more. Longshore currents are affected by the velocity and angle of a wave. When a wave breaks at a more acute (steep) angle on a beach, encounters a steeper beach slope, or is very high, longshore currents increase in velocity.
- In middle-latitude coastal oceans where evaporation is high, a halocline can develop. - Onshore wind and coastal runoff create geostrophic currents that flow northward along western North America. - In low-latitude areas where there is no mixing, surface water temperatures can be very high.
Stream erosion has removed softer rock from around the more resistant rock that forms the ridges here.
Each of the platforms and the ridges at the placemarks labeled C and E were formed by wave action —the platform at placemark B is currently "under construction," and those at the placemarks labeled D and F are older. What must have happened to produce the three platforms you see here?
The land rose (or sea level dropped) in at least two episodes. First, after the platform (a wave-cut bench) at placemark F was formed, the land rose approximately 130 meters, and the platform at the placemarks labeled D and sea stacks at placemark E were formed. A second uplift of approximately 30 meters left the platform at the placemarks labeled D 30 meters above sea level. The construction of the platform at placemark B began then and continues today.
The seafloor is very rugged, and depth increases quickly with distance from the shore.
a. Subduction zones rim the Pacific Ocean, while the Atlantic plate margins lack tectonic activity.
a. Sediment and seamounts are scraped from the subducting plate to form an accretionary wedge
d. Shallow subduction does NOT result in volcanism
The primary force (s) that cause (s) tides in the sea is (are): the gravitational attraction of the moon and the sun. A wave of water moving up a river, initiated by tidal action within a river estuary, is called a: tidal bore.
as a byproduct of photosynthesis and diffusion from the surface. The two most abundant elements (ions) dissolved in seawater are: sodium and chloride. The property of water that accounts for the ability of liquid water to absorb heat and change only very little in temperature is called: high heat capacity.
Because of the effect of cold water on the solubility of gases such as CO2, and the formation of carbonic acid, siliceous oozes are more abundant than calcareous oozes in polar waters.
Physical resources that are extracted from the ocean and are useful to humans include: petroleum and natural gas. The best fishing grounds are located: in temperate waters over continental shelves. An example of a fishing technique that is particularly disruptive is:
The origin of sea cliffs, sea stacks, sea caves, blowholes, and arches is related to: erosion by waves. An estuary in which salinities tend to be higher away from the ocean entrance than near the ocean entrance is called: a fjord estuary . The single most influential agent changing the shore and coast is: wave action.
A fast surface current of water that runs parallel to beaches and that causes a rapid decrease in water clarity (turbidity). The cause of mid-ocean trenches. A phenomenon associated with violent atmospheric storms at sea. none of these.
The salt content in the water under frozen sea ice is higher than the salt content in the ice itself due to salt being expelled from the ice lattice or structure.