Geology (and other Earth Sciences)
Geology (and other Earth Sciences)
There are three different types of sea floor sediments, the terrigenous sediment, hydrogenous sediment and the biogenous sediment. The terrigenous sediment is composed of material weathered from continental rocks. Hydrogenous sediment is made up of minerals that crystallize directly from seawater. The biogenous sediment has remains of marine animals and plants forming as its composites. There are various factors, which control the distribution of these sediments, most of which are unique to each type of sediment (Lutgens, Tarbuck, Tasa, 2011).
For instance, terrigenous sediment is mainly found in the continental margins of an ocean such as bays, estuaries, deltas and forms the most part of ocean sediments. Due to the nature of its composition, one factor that greatly affects its distribution is size. Terrigenous sediments are mainly coarse and can be transported by wind, glaciers and water from rivers and streams. Much of the coarse terrigenous material remains on the continental margins, and only small fractions of it are transported into the ocean. However, there are fine-grained terrigenous material, mainly red clay that often settles in the deep areas of the ocean basin.
Hydrogenous sediments make up a small part of the ocean. They are found in the deepest depths of the ocean. Many are the times that an expert was needed to verify their presence in a given ocean. Common minerals that form this sediment are manganese nodules, calcium carbonates and metal sulfides.
The distribution of biogenous sediments is controlled by factors such as productivity of marine organisms, dissolution and dilution into ocean water. Research reveals that productivity is high in areas with abundance in nitrogen and phosphorous, minerals essential for the growth of algae, which forms the base of the oceanic food chain. Such areas include certain coastal regions and areas along the equator. Therefore, biogenous sediments are mostly found in shallow areas of the open sea.
Salinity refers to the measure of concentration of dissolved salts present in seawater. Figure 9.4 in the textbook indicates how surface temperature of the ocean and surface salinity vary with latitudinal position. Normally one factor that increases salinity is high temperature, which leads to a high rate of evaporation of salts. The equator experiences high temperature levels together with increased rainfall. A decrease in salinity can occur if the amount of dissolved salts is decreased in the ocean or if the volume of water into which these salts dissolve is increased. It is therefore likely that salinity levels at the equator are low due to an increase in the amount of rainfall, which causes a significant rise in water volume in the ocean.
Rainfall at the equator is over a period implying occurrence of cloudier than sunny days. This factor affects the rate of evaporation of sea salts that occur in oceans along the equator. The position of the latitude at any given time affects the climate of a place. The equator stretches the diameter of the earth. Areas along the equatorial belt have hot and tropical climate. This means that they experience rainfall most times in as much as the temperature is extremely hot.
The large void in the ozone layer is commonly referred to as the ozone hole (Thompson, Turk, 2009). This phenomenon is due to a depletion of the ozone layer caused by chemical reactions involving taking place in the earth’s atmosphere. It occurred over the past few decades and is still an ongoing process. This continuous thinning of the ozone layer affects the earth’s atmosphere over the southern polar region known as the Antarctica. Its effects are that a high amount of harmful ultraviolet rays penetrates the earth’s surface in these regions. The effects of this void are deadly due to the harmful ultra violet rays. Too much of these rays results in eye damage, damage to the immune system, effects on DNA of various living organisms and skin cancer.
Global warming is the significant and continuous rise in the temperature of the earth’s atmosphere and its oceans. It is caused by what is known as the green house effect. This change has been attributed to human activities such as industrial pollution and deforestation. Some of the effects of global warming on living things include total climate change, food insecurity and displacement from habitats such as people living in islands due to rise in sea levels, which affects infrastructure.
During the winter season, there are four kinds of precipitation that can occur namely rain, freezing rain, snow and sleet. The case of St Louis, Missouri presents al possible forms of precipitation, with snow in the morning, rain by noon, sleet that later turned to snow and freezing rain in the evening. Moisture and temperature affect the amount and type of precipitation. St Louis is situated on the Missouri river valley, which has weather variations due to different atmospheric pressures. This implies that the snow in the morning was a result of low temperatures the previous night that extended to the morning.
By afternoon, temperatures had probably changed for the better due to human activities, traffic, and possibility that the sun came out. This change must have led to the liquefaction of snow into rain. However, this warmth was not enough to melt all the snow therefore part of it fell as sleet due to cold air. When the sleet hits the ground, it forms snow. Towards evening, temperatures fell to lower levels and probably there was an onset of winds. This cold air led to the cooling of surfaces such as bridges and roads. This cold air increased atmospheric moisture prompting rain to fall but freeze on the cold ground, which had already cooled.
Lutgens, F. K., Tarbuck, E. J., & Tasa, D. (2011). Instructor resource center on DVD [to accompany] Foundations of earth science, 6th ed. Lutgens, Tarbuck, Tasa. Upper Saddle River, N.J.: Prentice Hall
Thompson, Graham R., & Turk, Jonathan. (2009). Earth Science and the Environment. Brooks/Cole Pub Co.