18 resultados para 1930-1943
em Aquatic Commons
Resumo:
This bibliography attempts to list, with descriptive annotations and a subject index, important literature published between 1930 and 1953 dealing with the tunas and their fisheries in all parts of the world. It is thus a continuation of Corwin's (1930) work, which extended with similar scope through 1929, and an extension of Shimada's (1951), which was limited to the biology of Pacific tunas. The tunas with which it deals are those fishes customarily so-called in commercial parlance and usually classified in the genera Thunnus, Neothunnus, Parathunnus, Germo, Katsuwonus, Euthynnus and Auxis and their various synonyms. All aspects of the biology of the tunas are dealt with, as are descriptions and histories of all types of tuna fisheries, commercial and exploratory tuna fishing methods and results, fishing gear, catch statistics, and fishery management, but processing technology, economics and marketing, folklore, and purely literary references have been excluded.
Resumo:
In directly, phytoplankton serves as food for all aquatic animals since it is at the base of the food chain in which the phytoplankton-feeding animals are eaten by larger animals and these in turn are consumed by still larger forms. Hence, it becomes evident that the phytoplankton, its presence, and seasonal variations are of great importance. The report at hand is based on a record of the variations in the plankton population of surface waters at a single station, where collections were made biweekly from September 1943 through September 1945. The station chosen was in the channel of the Patuxent River, Maryland, near its entrance into Chesapeake Bay, about midway between the head and the mouth of the Bay. (PDF contains 31 pages)
Resumo:
The tectogene, or crustal downbuckle, was proposed in the early 1930s by F.A. Vening Meinesz to explain the unexpected belts of negative gravity anomalies in island arcs. He attributed the isostatic imbalance to a deep sialic root resulting from the action of subcrustal convection currents. Vening Meinesz's model was initially corroborated experimentally by P.H. Kuenen, but additional experiments by D.T. Griggs and geological analysis by H.H. Hess in the late 1930s led to substantial revision in detail. As modified, the tectogene provided a plausible model for the evolution of island arcs into alpine mountain belts for another two decades. Additional revisions became necessary in the early 1950s to accommodate the unexpected absence of sialic crust in the Caribbean and the marginal seas of the western Pacific. By 1960 the cherished analogy between island arcs and alpine mountain belts had collapsed under the weight of the detailed field investigations by Hess and his students in the Caribbean region. Hess then incorporated a highly modified form of the tectogene into his sea-floor spreading hypothesis. Ironically, this final incarnation of the concept preserved some of the weaker aspects of the 1930s original, such as the ad hoc explanation for the regular geometry of island arcs.