- 行业: Education
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Founded in 1876, Texas A&M University is a U.S. public and comprehensive university offering a wide variety of academic programs far beyond its original label of agricultural and mechanical trainings. It is one of the few institutions holding triple federal designations as a land-, sea- and ...
A project of the APL at the University of Washington School of Oceanography that studies the ice fracturing and the source of ambient noise as they relate to Arctic ocean temperature and sea ice thickness and concentration.
Industry:Earth science
The ratio of the mass of water vapor in a sample of moist air to a unit volume of the sample. It is expressed in grams per cubic meter and also called the vapor concentration.
Industry:Earth science
Small hills found only in the deep sea which rise from the ocean basin floor with heights ranging from 10 to over 500 feet and widths from a few hundred feet to a few miles. They are found along the seaward margin of most abyssal plains and originate from the spreading of mid-ocean ridges. As such, they usually form two strips parallel to mid-ocean ridges. They generally decrease in height as one traverses away from the ridges as they gradually become covered with sediment and are replaced by abyssal plains.
Industry:Earth science
This originally meant (before the mid-1800s) the entire depth area beyond the reach of fisherman, but later investigations led to its use being restricted to the deepest regions with a uniform fauna and low temperatures. Thus it was distinguished from the overlying bathyal or archibenthal zone with more varied fauna and higher temperatures. Eventually an underlying hadal zone was defined for areas in trenches and deeps below 6000-7000 m depth. The upper boundary of the abyssal zone ranges between 1000-3000 m, with the position of the 4° C isotherm generally considered the demarcation line. It is the world's largest ecological unit, with depths exceeding 2000 m comprising over three-quarters of the world ocean.
Industry:Earth science
One of five vertical ecological zones into which the deep sea is sometimes divided. There is a pronounced drop in the number of species and the quantity of animals as one passes into this zone. It is separated from the overlying bathypelagic zone by the 4° C isotherm and from the underlying hadopelagic zone at about 6000 meters. The distinction between pelagic and benthic species can be difficult to ascertain in this zone.
Industry:Earth science
An instrument used to perform in-situ measurements of the amount of chlorophyll in water. It does this by pulling water into two tubes, one measuring light absorption and the other attenuation. A beam of light with a wavelength rotating among three values is projected into each tube. The attenuation tube determines light absorption and scattering by measuring how much of the original light beam remains after it passes through the water inside the blackened tube. The absorption tube determines only how much light is absorbed by particles by measuring how much light is left of the original beam including that which has bounded off particles. This tube is lined with a quartz mirror which, in contrast to the absorbing black surface in the attenuation tube, reflects scattered light toward the detector. Chlorophyll causes a large change in the attenuation of light with a wavelength of about 676 nanometers, so a measurement of attenuation at the appropriate wavelength is a proxy measurement of chlorophyll concentration to first order. A fluorometer can also be used to measure chlorophyll.
Industry:Earth science
A German fluid dynamicist who was a pioneer in applying modern fluid dynamical methods to questions of the large-scale oceanic circulation.
Industry:Earth science
One of two groups into which plankton are divided, the other being phytoplankton. Zooplankton are a large group of micro- and macroscopic animals ranging in size from a fraction of a millimeter to 30-50 millimeters, with a few, such a certain jellyfish, being up to a meter in diameter. Some plankton, called permanent plankton or holoplankton, are adapted to a pelagic mode of existence and remain floating or feebly swimming throughout their entire life cycle. Others, called temporary plankton, are the transitory floating stages such as eggs, larvae, and juveniles of the benthos and nekton. This latter category is usually seasonal in occurrence and the abundance is primarily neritic since it derives from the benthos and nekton of shallow areas.
According to Rigby and Milsom (2000):
Members of the zooplankton have the widest geographical spread and greatest numerical abundance of any animals. Modern zooplankton are important contributors to global biomass and to the chemistry of the oceans, a dominant means of flux to the seabed, and a source of food for many large animals. The microzooplankton are dominated by flagellate protists, including some dinoflagellates and zooflagellates, and by amoebae such as foraminifera and radiolarians. Planktic ciliates are common, although the major group of these, the tintinnids, have proteinaceous tests and leave little record in the sediment. The macrozooplankton include a wide range of solitary and colonial cnidarians, chaetognath and polychaete worms, and holoplanktic gastropods. Crustaceans are among the most common macrozooplankton, with copepods, euphausiids, amphipods, ostracodes, and decapods all abundant and diverse. Urochordates are widespread with two planktic groups, appendicularians and salps. Larval stages of invertebrates and fish make up a significant proportion of the heterotrophic plankton in the modern ocean, remaining as part of the plankton for periods ranging from minutes to years.
Industry:Earth science
The distribution of the zonal mean of the eastward component of the wind through latitude and height. This is westerly through most of the troposphere, and peaks at speeds exceeding 30 m/s in the subtropical jet stream. Near the surface the zonal mean winds are westerly at most latitudes between 30 and 70°, with easterly winds prevailing a latitudes less than 30°.
Industry:Earth science
