Seiwell Harry Richard

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Harry Richard

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  • Book
    Application of the distribution of oxygen to the physical oceanography of the Caribbean sea region
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1938-09) Seiwell, Harry Richard
    Observational data for this discussion were obtained principally during the two cruises of the oceanographic research ship, "Atlantis," to the Caribbean Sea March 7 to May 5, 1933 (stations 1487-1610) and February 2 to March 2, 1934 (stations 1935-2002). The oxygen determinations, carried out on board, have been published in Bulletin Hydrographique (1934, 1935) together with other hydrographic data. The Caribbean Sea region falls into two natural bathymetric subdivisions: a western, lying between Yucatan Channel and a ridge extending from Honduras to Haiti via Jamaica, designated in this paper as the "Cayman basin," and an eastern, between this ridge and the lesser Antilles, here designated as the "Caribbean basin". "Cayman basin" has been used by Parr (1937) and by Rakestraw and Smith (1937), and, while antedated by "Yucatan basin" (Krümmel, 1907) it seems that less confusion will arise if the term "Cayman" is used in this discussion. The "Atlantis" observations supply for the first time the necessary information for a detailed study of the distribution of oxygen in the Caribbean Sea region. The 1933 and 1934 observations are here used indifferently; such a procedure seemed desirable since the data are insuffcient for determination of annual or seasonal variations, particularly in view of the disturbing effect which may be caused by short period vertical oscillations of relatively large magnitude.
  • Book
    The cycle of phosphorus in the western basin of the North Atlantic
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1935-04) Seiwell, Harry Richard
    The importance of phosphorus for organic production in the sea appears to have been recognized first by Brandt (1899) and the earlier determinations of this element in the coastal seas of northern Europe (Brandt, 1920; Raben, 1920; Mathews, 1917) suggested a correlation between seasonal variation of phosphate and growth of phytoplankton. These earlier determinations were later shown to be too high (Atkins, 1926, a) and did not indicate the complete exhaustion of phosphate from the water, so it was not until several years later that Atkins (1923), employing the rapid and more accurate colorimetric ceruleo-molybdate method of Deniges, illustrated the complete dependence of algal growth on phosphate (in the English Channel) and thus established the foundation for modern studies of marine chemical fertility. The beginning of our knowledge of phosphate content of the open ocean may, as far as is known to me, also be attributed to Atkins (1926, a) and even though these early results were frequently somewhat vitiated by storing of the samples before analyses, they represented the order of magnitude of phosphate concentration in the sea. Within recent years phosphate determination has become a component part of the program of most deep sea investigations and much general information on its distribution and variation in the open ocean has been brought to light.
  • Book
    Short period vertical oscillations in the western basin of the North Atlantic
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1937-05) Seiwell, Harry Richard
    Because of general interest in the subject of vertical oscillations in the sea and because such information is scanty for the ocean basins, an investigation of the question in the western North Atlantic was initiated by the establishment of "Atlantis" station 2639, July 9 to 13, 1936. The significance of vertical oscillations in the sea has been known from the earlier work of Helland-Hansen and Nansen, and, in 1926, these authors summarized their conception of the problem as follows: "By earlier investigations we have found that there are probably considerable vertical oscillations of the water layers in various regions of the ocean. Hence the occasional vertical series of observations cannot be expected always to represent the average conditions at any particular station. It is therefore of great importance for the discussion of the general conditions in a sea-area on the basis of the observations made, to study how far these actual observations at the different stations and different depths may be regarded as representative." Also, in this same paper we find the statements: "It has already been mentioned that the oscillations described have obviously to a great extent some connection with the tides; but how the tidal wave can produce vertical movements of such dimensions in the different strata of the sea seems to us at present to be inexplicable. We have here a phenomena of fundamental importance to oceanography, which has to be made the subject of special methodical investigations."
  • Book
    Results of research on surface waves of the western North Atlantic. I. Investigation of bottom pressure fluctuations and surface waves. II. Results of sea surface roughness determinations in the vicinity of Woods Hole, Mass., and Bermuda
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1948-08) Seiwell, Harry Richard
    Part I: It is to be expected that in the future, measurements of pressure fluctuations beneath the ocean surface will provide basic data for solution of many practical problems on the state of the sea. As a result of the wartime impetus, several types of underwater pressure recorders (of similar instrumentation principles) were developed both in this country and abroad. Essentially, the instrument consists of an underwater unit which electrically transmits pressure impulses near the sea bottom to a clockwork recorder installed on the shore. The underwater pressure unit is adjusted for pressure fluctuations resulting from surface waves within the spectrum band of periods set up by winds acting on the sea surface. The resulting records may be scaled for height and period of the pressure fluctuations over known time intervals. An accessory wave analyzer has been constructed for rapid periodogram analysis of the pressure records. This investigation is concerned with a comparative study of observed sea surface waves and recorded sea bottom pressure fluctuations. It was undertaken for the purpose of evaluating sea surface wave heights from sea bottom pressure recordings in the vicnity of Woods Hole and Bermuda. Part II: The results presented here comprise data on the state of the sea surface in the vicinity of Woods Hole (off Cuttyhunk Island, Massachusetts) July 1946 to May 1947, and off Bermuda, British West Indies, February 1947 to May 1947, obtained from analyses of automatic wave recordings. At both locations measuring elements of the wave recording instruments were located on the sea bottom (approximate depth 75 feet at Cuttyhunk and 120 feet at Bermuda) and electrically connected to shore recorders several miles away. The instrument operational schedules were continuous twenty minute recordings every two hours at Bermuda and every six hours at Cuttyhunk.
  • Book
    The effect of short period variations of temperature and salinity on calculations in dynamic oceanography
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1939-11) Seiwell, Harry Richard
    This paper is a discussion of possible discrepancies in computations of ocean currents (based on horizontal variations of dynamic topography calculated from arbitrary deep lying reference surfaces), because of time variations of temperature and salinity at fixed depths in the sea (illustrated for a 24-hour period at "Atlantis" Station 2639). The results contained herein, while based chiefly on information from the western North Atlantic, are of general applicability, since time variations of the same order of magnitude have been observed over extensive areas of the Atlantic ocean. In selecting material for analysis of dynamic situations in the region concerned, consideration has been given only to those favorably located stations from which the structural features could most conveniently be obtained for illustrating the points in question.
  • Book
    The distribution of oxygen in the western basin of the North Atlantic
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1934-08) Seiwell, Harry Richard
    The distribution of dissolved oxygen in the sea is controlled by a combination of its physical, chemical and biological characteristics; on the one hand, the chemical and biological activities tend to vary the content of the dissolved gas whereas, on the other, the circulatory agencies tend to redistribute the oxygen and bring about equilibrium. The fact that there is a constant consumption of dissolved oxygen in the depths and that frequent supersaturation with oxygen occurs at or near the surface of the ocean was observed on the "Challenger" expedition (Dittmar, 1884). An explanation of the cause of supersaturation of oxygen, however, was not forthcoming until 1899 when Martin Knudsen suggested that it was caused by photosynthetic activities of vegetable plankton. The original oxygen content of ocean waters has been obtained from a-thin surface layer in contact with the atmosphere and as a product of photosynthetic activity. In modern concepts of oceanography it is a generally accepted fact that the water masses of the depths of the oceans have at some time and place been at the surface where under the influence of climatic conditions they acquired distinct temperature, salinity and oxygen characteristics. The sinking of the surface layers in the so-called regions of convergence and their ultimate distribution by means of quasi-horizontal and convectional currents results in the whole of the ocean basins being filled with water which has acquired its fundamental characteristics while under the influence of atmospheric conditions. From general knowledge of oceanic circulation, based on researches of Nansen (1912), Jacobsen (1929), Wüst (1928), etc., the water of the western basin of the North Atlantic is probably of several origins and consequently of different ages and oxygen contents. Thus, the deepest part of the whole basin, up to depths of 2000-1500 meters appears to contain water which, for the most part, originated at the surface in high North Atlantic latitudes. Lying on top of this deepest water there is, in the northern half of the region, what appears to be a mixture of it and other North Atlantic water, while in the southern half of the region there is at intermediate depths a mass of water which apparently originated at the surface in high latitudes of the South Atlantic.
  • Book
    The minimum oxygen concentration in the western basin of the North Atlantic
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1937-05) Seiwell, Harry Richard
    With the advance in knowledge of oceanic circulation there now exists a demand for additional identifying properties which will serve to trace the origin and movements of water masses in the sea, and to check earlier conclusions based entirely on temperature and salinity distribution. Of all the known identifying properties (except temperature and salinity) oxygen appears to be the most useful, not only because of the ease with which it can be accurately measured at sea, but also because of the large amount of data available on its distribution in the open ocean.