Movement Of Water Masses Research Articles

Physical Oceanography and Submarine Geology of the Seas to the West and North of Alaska

Contains summary based on data collected in summers 1933 to 1952 by personnel of the U.S. Coast Guard, U.S. Hydrographic Office, Scripps Institution of Oceanography, University of Washington, and Canadian Navy, in Bering Sea and Strait, Chukchi, and Beaufort Seas. Submarine topography, bottom sediments, horizontal and vertical temperature and salinity structure, characteristics also origin and movement of water masses, currents, and ice conditions are briefly described.

On the Seasonal Abundance of Young Fish. VIII. the Year 1946, June to December

During the years 1930–9 a series of records was obtained on the abundance of pelagic young of teleostean fish occurring in standard half-hour oblique hauls made with the 2 m. stramin ringtrawl in the neighbourhood of the Eddystone. These results provided a record by which the composition of the young fish populations could be compared from year to year and any marked changes brought to notice. During the course of the observations there had been a striking reduction in abundance of young fish, and this had been correlated with the movements of water masses as indicated by certain plankton animals. The series of observations was brought to a conclusion in August 1939 on the outbreak of war. The earliest opportunity after the cessation of hostilities has been taken to continue these observations on young fish, and collecting was started in June 1946 when a research ship was once more available. There has thus been a gap of nearly seven years during which there has been no detailed information on the conditions in the waters off Plymouth. The 1946 collections were started too late to include the main period of abundance of young fish resulting from the spring spawners, but they afford evidence that as regards the summer spawners at any rate there is no significant change from the conditions existing in 1939. We cannot say what the conditions have been during the intervening years, but analyses of phosphorus content of the water during each of the winters in the period 1939–46 tend to show that conditions have remained much as they are at present, and that it is unlikely that there has been any large incursion of the rich water characterized by Sagitta elegans which supports a large population of young fish.

Observations of Water Trajectories in the Open Sea

DIRECT observations of continuous movements of water masses in the open sea do not appear to have been carried out before. We have, for this purpose, for some years been using free drifting current-crosses, followed by our research steamer the Skagerak. The crosses are made from two sheets of corrugated iron, intersecting at right angles, with the line of intersection vertical, and presenting an area to the current of approximately one square metre. They are suspended from a cylindrical buoy of small dimensions drifting at the surface with its axis vertical. The buoy carries a very light rod projecting upwards with a small electric lamp at the top, of the type used by drifters for their nets. By varying the length of the thin wire rope by which the cross is suspended from the buoy, one may study the water movements in different depths, since the small resistance due to the surface buoy does not affect the movements of the cross to any large extent, so long as the current below is not too weak relatively to the surface current. The positions of the buoy are observed at intervals of an hour or less by bringing up the ship as close to the drifting system as possible, without interfering with its movements. In daytime, with moderately strong currents, the movements of the buoy are followed from the ship at anchor by means of a Zeiss tele-meter. Such drifting systems have occasionally been followed right across the Skagerak from Skagen to the lighthouse Maseskar on the Swedish coast.