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Oceanography ch 6
Chapter 6 oceanography
| Question | Answer |
|---|---|
| absorption | Conversion of sound or light energy into heat. |
| acid | A substance that releases a hydrogen ion (H+) in solution. |
| active sonar | A device that generates underwater sound from special transducers and analyzes the returning echoes to gain information of geological, biological, or military importance. |
| adhesion | Attachment of water molecules to other substances by hydrogen bonds; wetting. |
| alkaline | Basic. See also base. |
| aphotic zone | The dark ocean below the depth to which light can penetrate. |
| Arctic Convergence | Convergence zone between Arctic Water and Subarctic Surface Water. |
| Arctic Ocean | An ice-covered ocean north of the continents of North America and Eurasia. |
| atom | The smallest particle of an element that exhibits the characteristics of that element. |
| base | A substance that combines with a hydrogen ion (H1) in solution. |
| bond | See chemical bond |
| buffer | A group of substances that tends to resist change in the pH of a solution by combining with free ions. |
| caballing | Mixing of two water masses of identical densities but different temperatures and salinities, such that the resulting mixture is denser than its components. |
| calorie | The amount of heat needed to raise the temperature of 1 gram (0.035 ounce) of pure water by 1°C (1.8°F). |
| chemical bond | An energy relationship that holds two atoms together as a result of changes in their electron distribution |
| chemical equilibrium | In seawater, the condition in which the proportion and amounts of dissolved salts per unit volume of ocean are nearly constant. |
| chlorinity | A measure of the content of chloride, bromine, and iodide ions in seawater. We derive salinity from chlorinity by multiplying by 1.80655. |
| cohesion | Attachment of water molecules to each other by hydrogen bonds. |
| colligative properties | Those characteristics of a solution that differ from those of pure water because of material held in solution. |
| conservative constituent | An element that occurs in constant proportion in seawater; for example, chlorine, sodium, and magnesium. |
| covalent bond | A chemical bond formed between two atoms by electron sharing. |
| deep zone | The zone of the ocean below the pycnocline, in which there is little additional change of density with increasing depth; contains about 80% of the world’s water. |
| degree | An arbitrary measure of temperature. One degree Celsius (°C) = 1.8 degrees Fahrenheit (°F). |
| density | The mass per unit volume of a substance, usually expressed in grams per cubic centimeter (g/cm3). |
| density curve | A graph showing the relationship between a fluid’s temperature or salinity and its density. |
| electron | A tiny negatively charged particle in an atom responsible for chemical bonding. |
| element | A substance composed of identical atoms that cannot be broken down into simpler substances by chemical means. |
| eurythermal zone | The upper layer of water, where temperature changes with the seasons |
| excess volatiles | A compound found in the ocean and atmosphere in quantities greater than can be accounted for by the weathering of surface rock. Such compounds probably entered the atmosphere and ocean from deep crustal and upper mantle sources through volcanism. |
| Forchhammer’s principle | See principle of constant proportions. |
| freezing point | The temperature at which a solid can begin to form as a liquid is cooled. |
| halocline | The zone of the ocean in which salinity increases rapidly with depth. See also pycnocline. |
| heat | A form of energy produced by the random vibration of atoms or molecules. |
| heat capacity | The heat, measured in calories, required to raise 1 gram of a substance 1° Celsius. The input of 1 calorie of heat energy raises the temperature of 1 gram of pure water by 1°C. |
| hydrogen bond | A relatively weak bond formed between a partially positive hydrogen atom and a partially negative oxygen, fluorine, or nitrogen atom of an adjacent molecule. |
| ion | An atom (or small group of atoms) that becomes electrically charged by gaining or losing one or more electrons. |
| ionic bond | A chemical bond resulting from attraction between oppositely charged ions. These forces are said to be “electrostatic” in nature. |
| Latent heat of evaporation | Heat added to a liquid during evaporation (or released from a gas during condensation) that produces a change in state but not a change in temperature. For pure water, 585 calories per gram at 20°C (68°F). Compare latent heat of vaporization. |
| latent heat of fusion | Heat removed from a liquid during freezing (or added to a solid during thawing) that produces a change in state but not a change in temperature. For pure water, 80 calories per gram at 0°C (32°F). |
| Latent heat of vaporization | Heat added to a liquid during evaporation (or released from a gas during condensation) that produces a change in state but not a change in temperature. For pure water, 540 calories per gram at 100°C (212°F). Compare latent heat of evaporation. |
| light | Electromagnetic radiation propagated as small, nearly massless particles that behave like both a wave and a stream of particles. |
| mixed layer | See surface zone. |
| mixing time | The time necessary to mix a substance through the ocean, about 1,600 years. |
| mixture | A close intermingling of different substances that still retain separate identities. The properties of a mixture are heterogeneous; they may vary within the mixture. |
| molecule | A group of atoms held together by chemical bonds. The smallest unit of a compound that retains the characteristics of the compound. |
| nonconservative constituent | An element whose proportion in seawater varies with time and place, depending on biological demand or chemical reactivity. An element with a short residence time;for example, iron, aluminum, silicon, trace nutrients, dissolved oxygen, and carbon dioxide. |
| oxygen minimum zone | A zone in which oxygen is depleted by animals and not replaced by phytoplankton |
| passive sonar | A device that detects the intensity and direction of underwater sounds. |
| pH scale | A measure of the acidity or alkalinity of a solution; numerically, the negative logarithm of the concentration of hydrogen ions in an aqueous solution. A pH of 7 is neutral; lower numbers indicate acidity, and higher numbers indicate alkalinity. |
| photic zone | The thin film of lighted water at the top of the world ocean. The photic zone rarely extends deeper than 200 meters (660 feet). Compare euphotic zone. |
| polar molecule | A molecule with unbalanced charge. One end of the molecule has a slight negative charge, and the other end has a slight positive charge. |
| principle of constant proportions | The proportions of major conservative elements in seawater remain nearly constant, though total salinity may change with location; also called Forchhammer’s principle. |
| proton | A positively charged particle at the center of an atom. |
| pycnocline | The middle zone of the ocean in which density increases rapidly with depth. Temperature falls and salinity rises in this zone. |
| refraction | Bending of light or sound waves as they move at an angle other than 90° between media of different optical or acoustical densities. See also wave refraction. |
| refractometer | A compact optical device that determines the salinity of a water sample by comparing the refractive index of the sample to the refractive index of water of known salinity. |
| residence time | The average length of time a dissolved substance spends in the ocean |
| respiration | Release of stored energy from chemical bonds in food; carbon dioxide and water are formed as by-products. (Respiration is a biochemical process and is not the same as the mechanical process of breathing.) |
| salinity | A measure of the dissolved solids in seawater, usually expressed in grams per kilogram or parts per thousand by weight. Standard seawater has a salinity of 350 at 0°C (32°F). |
| salinometer | An electronic device that determines salinity by measuring the electrical conductivity of a seawater sample. |
| saturation | State of a solution in which no more of the solute will dissolve in the solvent. The rate at which molecules of the solute are being dissolved equals the rate at which they are being precipitated from the solution. |
| scattering | The dispersion (or “bounce”) of sound or light waves when they strike particles suspended in water or air. The amount of scatter depends on the number, size, and composition of the particles. |
| sea ice | Ice formed by the freezing of seawater. |
| sensible heat | Heat whose gain or loss is detectable by a thermometer or other sensor. |
| side-scan sonar | A high-resolution sound-imaging system used for geological investigations, archaeological studies, and the location of sunken ships and airplanes. |
| sofar | Sound fixing and ranging. An experimental U.S. Navy technique for locating survivors on life rafts, based on the fact that sound from explosive charges dropped into the layer of minimum sound velocity can be heard for great distances. See also sofar layer |
| sofar layer | Layer of minimum sound velocity in which sound transmission is unusually efficient for long distances. Sounds leaving this depth tend to be refracted back into it. The sofar layer usually occurs at mid-latitude depths around 1,200 meters (4,000 feet). |
| solute | A substance dissolved in a solvent. See also solution. |
| solution | A homogeneous substance made of two components, the solvent and the solute. |
| solvent | A substance able to dissolve other substances. See also solution. |
| sonar | Sound navigation and ranging. |
| sound | A form of energy transmitted by rapid pressure changes in an elastic medium. |
| state | An expression of the internal form of matter. Water exists in three states: solid, liquid, and gas. A solid has a fixed volume and fixed shape, a liquid has a fixed volume but no fixed shape, and a gas has neither fixed volume nor fixed shape. |
| surface zone | The upper layer of ocean in which temperature and salinity are relatively constant with depth. Depending on local conditions, the surface zone may reach to 1,000 meters (3,300 feet) or be absent entirely. Also called the mixed layer. |
| temperature | The response of a solid, liquid, or gas to the input or removal of heat energy. A measure of the atomic and molecular vibration in a substance, indicated in degrees. |
| thermal equilibrium | The condition in which the total heat coming into a system (such as a planet) is balanced by the total heat leaving the system. |
| thermal inertia | Tendency of a substance to resist change in temperature with the gain or loss of heat energy. |
| thermocline | The zone of the ocean in which temperature decreases rapidly with depth. See also pycnocline. |
| thermostatic property | A property of water that acts to moderate changes in temperature. |
| trace element | A minor constituent of seawater present in amounts of less than 1 part per million. |
| tropics | The area between the Tropic of Cancer and the Tropic of Capricorn. |
| water mass | A body of water identifiable by its salinity and temperature (and therefore its density) or by its gas content or another indicator. |
Created by:
Academic Center