Deep Sea Research (1953)最新文献

Iodine in sea water samples from the Northeast Pacific and Arctic Oceans was determined by two independent methods of analysis, one of which was also capable of determining iodate. Both oceans showed a constant iodine-chlorinity ratio of 3·3 × 10⁻⁶ at depths from 250–4000 metres. Some significant variation was observed in the iodine chlorinity ratio in the surface layers. In the North Pacific from one- to two-thirds of the total iodine was present as iodate, with no discernible trends with depth or location. In the Arctic, the iodate increased with depth — from a minimum near the surface to a maximum at 500–1000 metres-where 100 per cent of the iodine was found to be iodate. More iodate was present in the Arctic from 200–2000 metres than was present in any North Pacific sample.

Inland waters of the State of Washington showed iodine-chlorinity ratios about 15 per cent lower than oceanic stations, probably due to accumulation of iodine by benthonic algae.

By means of oil capillaries the indicator attenuates the tidal rise and fall of the sea surface, as well as all fluctuations of higher frequencies. The time constant of the response is chosen so that the smaller, slower fluctuation of sea level is transmitted with very little change of amplitude and phase. There is no recorder. Visual reading of the oil level in a burette should be tabulated twice a week. Installation of the instrument is much easier and cheaper than a recording tide gauge.

The hydrography and abundance of phytoplankton were studied at three stations located in the equatorial Pacific, March 1957. Water bottle samples preserved with neutralized formalin were used for the phytoplankton study, which included the smaller forms of diatoms, dinoflagellates and coccolithophorids. Difficulties in obtaining reliable estimates in the case of poor populations were overcome by a simple concentration technique.

The quantity of phytoplankton, computed as number of cells under 0·1 m², was found to be much the same as the maximal figure for the Sargasso Sea and the amount obtained before and after the time of maximal population in the antarctic and subantarctic Pacific.

In the equatorial Pacific phytoplankton abundance was restricted to the upper 50 to 100 m. Maxima in the numbers of diatoms were found nearer the surface than those of dinoflagellates, while the coccolithophorids showed different patterns in their vertical distribution. “Olivgrüne Zellen” (Hentschel) were present at the greatest sampling depths.

A pennate diatom species, athecate dinoflagellates and certain small coccolithophorids were the most numerous forms observed.

Circumstantial evidence of seasonal variation is discussed.

The distribution of a planktonic worm, Poeobius meseresHeath, was determined from an examination of over 1800 quantitative plankton tows taken in the North and South Pacific. This distribution is compared with the distribution of water masses, as defined by temperature-salinity curves. Since the water mass concept involves a three dimensional unit of the ocean, its use in describing the environment of an animal whose distribution is also three dimensional, is preferable to the method of comparing plankton distributions with horizontal isotherms or isohalines.

The distribution of Poeobius coincides, for the most part, with that of the Subarctic water mass and the transition region of Subarctic water, the California Current. However, a few specimens were found in the eastern tropical Pacific. A satisfactory explanation for its restricted presence in this latter area is not possible at this time, but there is some evidence to indicate that this southern segment of the population is not endemic but has been carried in from the north. If this is true, then the occurrence of Poeobius here must be accounted for in considering the sources of the Intermediate water of the area.

In accordance with plans for the International Geophysical Year, the Marine Antarctic Expedition of the U.S.S.R. Academy of Sciences began oceanographic work, especially work in submarine geology, in 1955 in the Antarctic and in the Indian Ocean. Echo soundings in South Polar seas were taken over tens of thousands of miles, particularly in little known areas and new submarine elevations were found in an extensive area of recent volcanic activity west of the submarine mountain range extending between Kerguelen and Gaussberg. For the first time in Antarctic waters, cores up to 16 m long were obtained and samples of bottom sediments were collected on the two voyages at more than 200 stations. A systematic study was made of the distribution and composition of particles suspended in sea-water, as well as the seismo-acoustic work on the thickness of the unconsolidated sediments on the ocean bottom. The expedition is at present continuing work in the Indian and Pacific Ocean.

The colour intensity of the molybdate-blue complex in the analysis for inorganic phosphorus in sea-water increases 1·25 per cent per degree centigrade. The apparent phosphorus content of sea-water samples analysed in tropical regions may be erroneously high unless temperature is controlled or corrections are made. The effect of temperature correction on the agreement between total and inorganic phosphorus contents of Atlantic Ocean water is described. It is recommended that temperature corrections be included in future publications of data on the distributions of inorganic phosphorus.

An approximation valid near the equator is developed for a model of the general thermal circulation. The existence of equatorial effects is related to the vanishing of the Coriolis parameter, and the equatorial approximation is related to the mid-latitude circulation. Qualitative features of the solutions are discussed.

Direct current measurements made along the equator in the central and eastern tropical Pacific during the IGY show that the subsurface eastward flow, first described in 1954, is a fast, thin, but major current. As defined by the 25 cm/sec contour, it is 300 km wide and about two-tenths of a kilometre thick; it is symmetrical about the equator. At 140°W the core of the current is at 100 m. Velocities up to 150 cm/sec (3 knots) were recorded. The average transport based on four sections is 39 × 10⁶ m³/sec. The current was traced from 140 °W to the Galapagos Islands at 92°W. It was not found east of the Galapagos at 89°W. The core velocity was 100–150cm/sec from 140°W to the Galapagos; the depth of the core shallowed from 100 to 40 m. At the surface and at 500 m the flow was to the west.

Hydrographic measurements suggest that the flow is in geostrophic equilibrium to within half a degree of the equator. The major features of the Pacific Equatorial Undercurrent (Cromwell Current), including its general shape, the depth of the core, which slopes upward to the east, can be accounted for by assuming a geostrophic flow in response to the perturbation in the horizontal pressure gradients caused by mixing through the thermocline at the equator.

Direct measurements of the Cromwell Current show that the current extends from at least 92°W to 150°W (3500 miles). Indirect evidence suggests that the current will be found to at least 170°W (4700 miles long) and perhaps as far as 160°E (6500 miles long).