1. What are the different types of seafloor sediments, and what are the factors that control the distribution of each major sea sediment type? Where does each major seafloor sediment type tend to accumulate in greatest quantity?
Sediment on the seafloor originates from a variety of sources, including small living organisms from the overlying ocean water, eroded material from land transported to the ocean by rivers or wind, ash from volcanoes, and chemical precipitates derived directly from seawater. A very small amount of it even originates as dust from outer space! In short, the particles found in sediment on the seafloor vary considerably in composition and record a complex interplay of processes that have acted to form, transport, and preserve them in Earth's composition.
The transport of sediment depends on its ultimate size and where it was originally produced. Terrigenous sediment can be transported to the deep sea via rivers or by wind. Material transported by rivers most commonly ends up deposited on the continental margin, that is, the area that surrounds landmasses of the Earth.
When continental margin deposits accumulate fast and get overly steep, or when an earthquake or storm causes the sediment to be disturbed, currents can stir the material up and ultimately provide additional transport out to the deep sea.
The transport of sediment by wind is also extremely significant, and is particularly relevant to studies of Earth's climate in the past. When the Earth's climate is relatively dry the land surface tends to be more dusty, and thus during such periods there will be more windblown terrigenous material delivered to the

deep ocean. Also, during such time periods the wind speed tends to be higher, and thus terrigenous grains that are slightly larger than usual are preferentially transported according to the direction of the prevailing wind. Thus, by examining the amount of dust, as well as the various grain size, in the different layers of a sediment core, oceanographers learn how arid the land surface was at a given time, as well as how fast the average wind speeds were (Murray, 2012).
2. A variety of techniques and efforts are used to stabilize shorelines throughout the world. Discuss these techniques. Are they temporary or permanent? Also, discuss at least two ways in which the development of coastal areas contributes to shoreline erosion? (Hint: think about rivers and what they contribute to our beaches. Also, what increases with the creation of roads and rooftops?)
Shoreline erosion is a natural process that occurs on lakes, streams, rivers, and along the coast. It is the gradual, although sometimes rapid, removal of sediments from the shoreline. It is caused by a number of factors including storms, wave action, rain, ice, winds, runoff, and the gradual loss of trees and other vegetation. Although erosion is not intrinsically harmful, when it is augmented to the point where it affects natural resources, water quality, ecosystems, and property loss, it is generally undesirable. Even trying to stabilize the various shorelines can also contribute to its erosion over time. Fortunately, there are various techniques for helping to preserve our natural shorelines. These may include building a habitat

somewhat artificially to help protect the shoreline. In addition, one may wish to protect the native vegetation in an area that will also provide an ecosystem for game and wildlife in the area. These processes are somewhat temporary as the movement of sediment is always changing. Nevertheless, it is an excellent way to try to protect the shoreline (New York State, 2012).
Human intervention may be harmful to the shoreline as we move forward with our plans to populate the Earth. As we build roads and rooftops, there is an increase in the amount of storm water run off that affects our natural shoreline. In addition, when we enjoy a river, we may not realize that the waterway is actually contributing to the build up of sediment that may negatively affect our coastlines and shoreline habitats.
References
Ernst, W. G. (1982) The Environment of the Deep Sea. Upper Saddle River, NJ:
Prentice-Hall
New York State (2012) "The Shoreline Stabilization Handbook" Northwest
Regional Planning Commission. St. Albans, Vermont.