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Oceans LAB FINAL
World Oceans
| Question | Answer |
|---|---|
| Methods of Marine positioning | Dead reckoning. Radar and Bearing. Sextant. LORAN-C. Satellite navigation. |
| Dead reckoning | Requires knowledge of your ships present position and speed. Knowing the boats position on a chart and the position of your destination, a heading and distance can be plotted. Using the boat speed, the travel time can be calculated. |
| Radar and Bearing | Using radar, the distance and bearing from a known point on land can be obtained. By using at least one fix, the position of a ship can be obtained. This method is only workable close to land areas seen by radar. |
| Sextant | Used for both open ocean and coastal navigation. Used vertically for celestial navigation by measuring the altitude of the sun or star above the horizon. Used horizontally for coastal navigation to measure the angle between charted landmarks. |
| LORAN-C | A radio navigation system. Used by ships and aircrafts in all weather conditions over land and sea to obtain high accuracy position information. Now being replaced by GPS |
| Satellite Navigation | GPS. |
| Latitude | N & S. Stated first. Measured along a meridian. One degree of latitude is equal to 60 nautical miles, and one minute of latitude is equal to 1 nautical mile. |
| Longitude | E & W. Measured using meridians starting usually at the prime meridian. |
| Magnetic North | The direction that the needle of a magnetic compass points. |
| True North | The direction of geographical north. |
| Heading | The direction in which the ship actually travels. |
| Course | The intended direction of travel. |
| Calculate depth. | Depth=velocity*Time/2 |
| Rules of Contouring. | 1. Contour lines connect points of equal depth. 2. Contour lines may never cross each other. 3. Once a line has been drawn, it must separate a shallower area from a deeper one. |
| Rules of Contouring. | 4. Honor all data. No depths greater than a contour line should be found in the shallower sea. 5. Contours of trenches exhibit a V-shaped pattern with the apex of the V pointing upstream or to the shallower sea. |
| Rules of Contouring. | 6. Closely spaced contours indicate a steep slope and widely spaced lines indicate a gentle slope. 7. Contour lines cannot end abruptly. |
| Early Bathymetric data was acquired using: | Weighted rope. Then piano wire. These were inaccurate due to currents, limited depth measurements, and small coverage area. |
| Bathymetric data is now collected using: | An echo sounder or fathometer. Precision depth recorder. Acoustic seismic profiling. |
| Contour interval. | The distance between the contour lines. |
| Contour line. | Lines that connect points of equal elevation or depth. |
| Cross section. | Two dimensional views of a portion of a bathymetric contour chart. |
| Bathymetry. | The measuring and charting of the sea floor. |
| Siliceous oozes. | Comprised of silica, Si02, and are comprised dominantly of skeletal material of radiolarians, diatoms, and sponge spicules. |
| Calcareous oozes. | Composed of calcium carbonate, CaCO3, and are comprised dominantly of skeletal fragments of foraminifera, coccoliths, and pteropods. Do not exist at depths below 3500 in the Pacific or 4500 in the Atlantic. |
| Carbonate Compensation Depth. | The depth (3500 in the Pacific, 4500 in the Atlantic) at which Calcium Carbonate material dissolves due to high pressures and cold temperatures. |
| Lithogenic sediments. | Derived from ricks and include 3 kinds of ocean sediments: terrigenous, volcanic, and comogenic. |
| Terrigenous sediments. | Broken pieces of rocks. Sand, silt, and clay sized. |
| Volcanic sediments. | Commonly associated with islands and mid-ocean ridges. Produces pillow lava. |
| Cosmogenic sediments. | Sediments originating from space including meteorites and atmospheric dust. |
| Biogenic sediments. | Those composed of particles of material derived from the skeletons of plants and animals commonly living near the surface of the oceans. Significant quantities of this material can accumulate on the seafloor and are known as oozes. |
| Hydrogenic sediments. | Derived through direct precipitation from seawater. Salt and gypsum are the result of precipitation due to evaporation in shallow marine areas, usually near shorelines. In deeper water, manganese, copper, and phosphate nodules are common. |
| Classification of rocks. | Grain size. Sorting. Texture. |
| Grain size. | The size of the grains. THis is usually determined by water energy. |
| Sorting. | Sorting is a measure of the uniformity of grain sizes in a sample. |
| Texture. | Angularity or rounding of grains, frosted surfaces, and other features. |
| Visibility | A measure of depth to which one may see into the water. |
| How do you measure visibility? | Using a secchi disc. |
| Reasons why visibility would change. | Water quality due to solids such as phytoplankton, clay particles, and other debris. |
| Dissolved oxygen. | Introduced in one of two ways. 1. Aeration, the mixing of the water supply with the atmosphere above it. 2. Through photosynthesis process of aquatic flora. Oxygen is removed by respiration of organisms and organic decomposition. |
| Seawater's chemical and physical properties: | Salinity: 35 ppt. pH: 8.1. |
| Density. | Density will increase as water cools or salinity increases. |
| Nitrates. | Usually from a man made source such as fertilizer, sewage, and industrial waste. Essential for plant growth but too much presents a major pollution problem. |
| Sulfides. | Result from normal bacteria growth on organic matter or in waters where sewage or industrial wastes are being introduced. Toxic respiratory depressant in both man and fish. |
| Salinity. | The total amount of solid material dissolved in sea water. |
| Carbon Dioxide. | Used by aquatic plants for photosynthesis. As oxygen concentration decreases, carbon dioxide concentration increases. |
| Crest. | Top of the wave. |
| Trough. | Bottom of the wave. |
| Wavelength. | Distance from one crest to the next crest, or from one trough to the next trough. |
| Wave height. | The vertical distance from trough to crest. |
| Wave period. | The length of time for a wavelength to pass a fixed point. |
| Breakers. | Spilling, plunging, or surging. |
| Spilling. | Gradually break, slowly releasing energy and changing waveform as they travel across the shoreline. |
| Plunging. | Suddenly break, quickly releasing energy and drastically changing waveform as they feel bottom. |
| Surging. | Occur on shorelines with more modern angles of slope. Build up like a plunging breaker but then the wave base surges shoreward before the top of the wave can break. |
| Deep water waves. | Occur where the depth of the water is greater than half the wavelength. Water particle movement is circular and the diameter of the circles decreases with increasing depth. |
| Shallow water waves. | Shallow water waves' particles move into flatter orbits that become increasingly flattened with depth. |
| Waves are generated by: | Wind, seismic disturbance, and atmospheric pressure changes. |
| Gastropoda-snails | Coiling and tortion plus reduction. |
| Bivalia- Pelecupoda | Compression, 2 valves, muscles, head. Ex. Oysters, Clams, mussels. |
| Cephalopoda | Shell, siphuncle, chambers, hyponome, tentacles. Ex. Squid, octopus, CUTTLEFISH! |
Created by:
Jenni_B
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