Ripple Height and Length Predictors - Essay Example

Ripple Height And Length Predictors (Coastal Environment) The sediments of the sea floor may be divided into lithogenous, hydrogenous, biogenous, and cosmogenous sediments. Lithogenous sediments are the major sediments on the ocean floor. They are derived from the chemical and mechanical weathering of rocks. Biogenous sediments are composed primarily of the protective outer covering of small marine animals and plants. If these remains comprise at least thirty percent of the sediment it is called an ooze. Oozes were named for the types of organisms that formed them. Hydrogenous sediments form as a result of the chemical reactions that occur in the seawater. These reactions result in the formation of small particles, which are deposited on the sea floor. Currents move these particles and cause them to collide with the other particles. If many of these collisions occur they may form nodules. Nodules are found on some portions of the deep-sea floor. The sediment type frequently determines the type of organisms that will be found in that specific area. Waves are variable and transitory features of the seas surface. (Sandra Smith) All waves, from the smallest ripple to the most destructive tsunami, have common characteristics. They all have crests, troughs, wave heights, lengths, and periods. Also, water particles that make up the waves all move in identical orbital patterns. The orbital pattern is up and forward in the crest and down and back in the trough. It is only when the wave becomes unstable that the orbital motion is destroyed. The water particles then begin to move at the same speed as the moving waveform. Breaking waves release a tremendous amount of stored energy on a beach face. This energy moves the sand about and changes the configuration of the bottom. As the bottom configuration is changed by the waves, it changes the characteristics of incoming waves. This interaction between the waves and the bottom results in the beach face having an everlasting wave pattern. Everything in the universe is composed of extremely small particles called atoms, which are often bonded together to form molecules. Molecules are formed as the result for the transfer of electrons between atoms. The complete loss and gain of electrons results in the formation of ionic molecules, which have completely positive and negative vegions. Unequal sharing of electrons, on the other hand, characterizes the polar covalent molecules, which have only partially positive and negative regions. The equal sharing of electrons result in the formation of nonpolar covalent molecules, which do not develop charged regions. Due to the development of charges on ionic and polar molecules, intermolecular attractive forces form between these molecules, intermolecular attractive forces form between these molecules and enable the compounds to exist in the solid and liquid state. Ionic compounds have long-range order and exist as solids. Polar covalent molecules are liquids because of their short-range order, while the nonpolar gases do not develop intermolecular attractions and as a result exhibit no order. Changes in state are due to a change in the order of compounds. When energy is added, molecular motion increases and intermolecular attractive forces are disrupted. This results in the melting of solids and the evaporation of liquids. When energy is removed, the molecular motion is decreased, which increases the formation of intermolecular attractive forces. This allows vapours to condense as liquids to freeze. The physical and chemical components of water interact with and affect the plant and animal life in the sea. The plants, animals, and bacteria that inhabit a given marine area continually react with, change, and are changed by the total biotic and a biotic environment. Light plays a vital role in the sea, since the producers require sunlight as the energy source to convert the low-energy simple plant nutrients into the more complex high-energy molecules that can be used by the consumers. The dominant plants of the sea are the microscopic phytoplankton, while copepods. The copepods are important, since they provide the major link in the transfer of energy from the phytoplankton to the large animals of the sea. Density exerts profound effects on both the biotic and biotic components of the sea. Many marine forms, both animal and plant, have developed unique life-styles of seawater. In addition, density barriers are formed in the sea in response to temperature and salinity differences between water masses. In many cases these density barriers trap nutrients below the euphotic zone and make them spatially unavailable to the plants in these areas. This is the case in the tropical seas, as well as in all of the worlds deep oceans, where the density barriers are permanent. Plant nutrients tend to cycle throughout marine systems, from their simple, low-energy, dissolved forms to plants, animals, and then to bacteria. When considering the cycling of nutrients through any system, it is important to remember that matter and energy are inter-changeable. Cycles that encompass both the biotic and biotic components of a system are called biogeochemical cycles. Biochemical cycles involve the transfer of the essential, minor, and trace elements from the biotic to the biotic components of a system. The transfer of food is extremely important in marine life. The transfer of food energy may be depicted by food chains and food webs. Food chains can be and generally are unstable, since the loss of a single link can have drastic effects on the remainder of the chain. Food webs are more stable, since a variety of alternate food sources exist at each trophic level. Wind-drift currents are formed by wind moving across the surface of the sea and setting water in motion. Winds are formed by the warning and cooling affects the density of the air, causing it to move into adjacent air masses. Once in motion, both air and water masses are influenced by the rotation of the earth. This causes the water masses to appear to deflect to their right in the Northern Hemisphere and to their left in the Southern Hemisphere. As a result, the major wind currents appear to travel in large figure eights from the equator northward and southward. Density currents involve a large percent of the seas volume. Since these currents are the result of temperature and salinity differentials that develop between adjacent water masses, they are often called thermohaline currents. The thermohaline circulation travels through the subsurface waters of all of the worlds oceans. These currents carry oxygen to the ysphotic zone, where because of the absence of light, photosynthesis cannot occur. They also remove large amounts of nutrients from the euphotic zone and transport them for great distances throughout the deep ocean. The current patterns in estuaries are also generally formed in response to density differentials. Depending on the amount of marine and fresh water that enters these systems, estuaries may be highly or moderately stratified, vertically homogeneous, or hepersaline. The resultant salinity variations in these areas has a direct influence on the biotic distributions in estuaries. Shorelines are the point of contact between the marine and terrestrial environments and, as such, are flooded at high tide and exposed at low tide. They are only a part of the coastline or coastal zone, inland and for hundreds of miles along a shoreline. Shorelines are constantly changing. Coastal sediments are continually attacked and reworked by the sea. Waves move these sediments into the surf zone, where they are picked up and transported by the long-shore current. Those sediments are sorted by this currentand eventually deposited to form such major coastal features as barrier islands and sand splits. Inlets form, migrate, close, and reform along barrier beaches. A combination of inlet formation, closure, and the overwash of a barrier beach during storms causes the barrier island to migrate towards land. Bibliography Amin, S. M. N., and Davidson-Arnott. 1997. A statistical analysis of the controls on shoreline erosion rates, Lae Ontario. Journal of Coastal Research 13:1093:1101. Bauer, B. O. 1990. Assessing the relative energetics of "infragravity" motions in lakes and bays. Journal of Coastal Research , 6:853-865. Bauer, B. O. Sherman, D. J., Nordstrom, K. F., and P.A. Gares, P. A. 1990. Aeolian transport measurement and prediction across a beach and dune at Castroville. In Coastal Dunes: Form and Process, eds. K.F. Nordstrom, N.P. 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