Showing papers by "National Institute of Oceanography, India published in 1970"
01 Jan 1970-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this paper, the evolutionary history of the Gulf of Aden has been worked out using seafloor bathymetry data from the International Indian Ocean Expedition, especially from cruise 16 of R. R. S. Discovery.
Abstract: Marine geological and geophysical data from the International Indian Ocean Expedition, especially from cruise 16 of R. R. S. Discovery , have made it possible to prepare new charts of the bathymetry and the magnetic anomaly field which, together with other data, enable the evolutionary history of the Gulf of Aden to be worked out. Over the past 10 Ma the theory of seafloor spreading can account satisfactorily for the features of the Sheba Ridge and provides evidence of spreading rates in the direction of the fracture zones varying from 0.9 cm a -1 per limb in the west to 1.1 cm a -1 per limb in the east. Between the initial creation of the Gulf and 10 Ma ago, the evolution is less certain, although the geophysical evidence indicates that the crustal structure of the Gulf outside the Sheba Ridge is oceanic.
222 citations
TL;DR: Ribbons have been found by the side-scan Asdic method in most of those areas of the sea floor around the British Isles where tidal currents have maximum near surface velocities of 2 knots or more as mentioned in this paper.
154 citations
TL;DR: In this paper, side-scan Asdic and echo-sounder data was used to investigate the widespread occurrence of sand ribbons, sand waves and sand patches on the continental shelf west of the British Isles and France.
Abstract: SUMMARY
Extensive data obtained by side-scan Asdic and echo-sounder equipments, viewed in conjunction with bottom notations on navigational charts and some seabed samples, show the widespread occurrence of sand ribbons, sand waves and sand patches on the continental shelf west of the British Isles and France. The close similarity of their directional trends with those of the strongest tidal currents strongly suggests a causal relationship which applies to much of the continental shelf, parts of the upper continental slope and also to off-lying shoals such as Rockall Bank. The sand transport paths broadly parallel the coasts in the epicontinental seas and on the open shelf west of the British Isles. In contrast, the paths are substantially normal to much of the coast of western France.
142 citations
TL;DR: Angel et al. as mentioned in this paper described the biological results of a detailed investigation of the ecology of an oceanic area located in the eastern North Atlantic, close to the island of Fuerteventura (Canary Islands).
Abstract: This study forms a contribution to a series (Angel, 1969; Clarke, 1969; Baker, 1970; Badcock, 1970) describing the biological results of a detailed investigation of the ecology of an oceanic area located in the eastern North Atlantic, close to the island of Fuerteventura (Canary Islands). The scientific background and objectives of the investigation, conducted during September to December 1965, have been described elsewhere (Currie, Boden & Kampa, 1969). Our main interest lay in the biological composition and acoustic characteristics of sonic scattering layers, and it was therefore considered essential to sample the principal elements of the pelagic fauna within the depth range 0–1000 m in as quantitative and detailed a manner as was technically possible. The resulting biological collections represent a unique body of material, the analysis of which is directly pertinent to the vertical distribution, diurnal migration and ecological interrelationships of the mesopelagic fauna.
112 citations
TL;DR: The features of the vertical distribution of meso- and bathypelagic fishes are poorly known as mentioned in this paper, and much of the present knowledge is based upon data collected on the early, major expeditions (i.e., Brauer, 1906; Murray & Hjort, 1912; Jespersen, 1915; Jørgenson & Taning, 1926; Norman, 1929, 1930; Regan & Trewavas, 1929 and 1930; Benin, 1934, 1937; Ege 1934 1948, 1953, 1957; Bertelsen, 1951; Parr
Abstract: The features of the vertical distribution of meso- and bathypelagic fishes are poorly known. Much of our present knowledge is based upon data collected on the early, major expeditions (i.e. Brauer, 1906; Murray & Hjort, 1912; Jespersen, 1915; Jespersen & Taning, 1926; Norman, 1929, 1930; Regan & Trewavas, 1929, 1930; Benin, 1934, 1937; Ege 1934 1948, 1953, 1957; Bertelsen, 1951; Parr, 1960; Ebeling, 1962; Ebeling & Weed, 1963; Nafpaktitis, 1968). Fishing depths were not accurately determined, the depth of net generally being calculated from the length of wire out and the wire angle to the water surface. Closing nets were infrequently used. From these reports a general appreciation of vertical distributions has been possible. More recently, distribution studies mostly made in restricted areas using open nets with depths more accurately determined indicate a limited vertical distribution for each species (Aron, 1962; Pearcy, 1964; Pearcy & Laurs, 1966; Lavenberg & Ebeling, 1967; Paxton, 1967).
107 citations
TL;DR: In this article, the second and final part of a study of the depth distribution and diurnal migration of decapod crustaceans in an area of the eastern North Atlantic is presented.
Abstract: This paper represents the second and final part of a study of the depth distribution and diurnal migration of pelagic decapod crustaceans in an area of the eastern North Atlantic. Part I (Foxton, 1970) dealt with the Caridea; Part II now considers the Penaeidea. In the discussion the data as a whole are analysed and the resulting patterns of vertical distribution and migration discussed.
92 citations
TL;DR: Among the long sand banks of the southern North Sea, off Norfolk new sand wave and current data indicate a northerly flow of sand on the western sides of the banks and southerly flow on their eastern slopes.
83 citations
TL;DR: In this article, a mathematical expression for the relationship between specific gravity, salinity and temperature has been computed for natural sea waters covering the salinity range 9 − 41% at temperatures of 0 − 25°C.
71 citations
TL;DR: A bloom of Trichodesmium erythraeum occurred in great profusion in the Laccadives and largely occupied the upper few meters of the water as mentioned in this paper.
69 citations
TL;DR: A detailed study of the vertical distribution of the micronekton, plankton and sonic scattering layers in the upper 1000 m at a position off Fuerteventura in the Canary Islands was carried out by Currie, Boden & Kampa as mentioned in this paper.
Abstract: During the autumn of 1965 a detailed study was carried out by members of the National Institute of Oceanography and Scripps Institution of Oceanography into the vertical distribution of the micronekton, plankton and sonic scattering layers in the upper 1000 m at a position off Fuerteventura in the Canary Islands. This is one of a number of similar papers by various authors on the vertical distribution of the animal groups sampled (Angel, 1969; Clarke, 1969). A background to the investigation, including the hydrology of the area studied, has been given in an introductory paper by Currie, Boden & Kampa (1969).
67 citations
TL;DR: The structure of the head of the sperm whale (Physeter catodon) was described in outline by Pouchet and Beauregard1–3 and by Raven and Gregory4, but the function of the large, wax filled spermaceti organ and related structures is not known.
Abstract: THE structure of the head of the sperm whale (Physeter catodon) was described in outline by Pouchet and Beauregard1–3 and by Raven and Gregory4, but the function of the large, wax filled spermaceti organ and related structures is not known although several theories4–6 have been advanced.
TL;DR: Observations were made on 2 beaches during the premonsoon period (January to March) when conditions were relatively stable, and the water temperature remained about 31°C, but on the dry sand surface it reached 50°C and the amount of chlorophyll attached to sand grains is very small.
Abstract: Observations were made on 2 beaches during the premonsoon period (January to March) when conditions were relatively stable. The beach below the berm at Cochin is 14 m wide with a slope of 1 in 8.5, and at Shertallai 40 m wide with a slope of 1 in 16. The well-sorted sand has a mean particle size of 275 μ at Cochin and 175 μ at Shertallai. The amount of chlorophyll attached to sand grains is very small. Chlorophyll in the water varies between 0.9 and 13.0 μg/l. Carbon in the sand amounts to 210 to 630 μg/g, and in the water to 355 to 3660 μg/l. Throughout observations, the water temperature remained about 31°C, but on the dry sand surface it reached 50°C. Fauna zonation on the 2 beaches is similar to that of other tropical beaches; crabs of the genus Ocypode and the isopod Eurydice sp. occur at high water mark, the polychaetes of the genera Glycera, Onuphis, Scoloplos and Lumbrinereis in the mid-intertidal region and below; the tidal migrants Bullia melanoides (Gastropoda), Donax incarnatus and D. spiculum (Bivalvia) and Emerita holthuisi (Crustacea) inhabit the wash zone of the surf. The average biomass is 0.73 g carbon/m2 at Shertallai and 0.85 g C/m2 at Cochin, where fewer species are present. This compares with a value of 0.63 g C/m2 for a sandy beach on the west coast of Scotland.
TL;DR: In this article, the profile of the streaming velocity is calculated for circular islands, with or without shoaling regions offshore, and it is shown that resonance with the free modes trapped by the shoaling region may greatly increase the streaming velocities.
Abstract: An oscillating current such as a tidal stream or an inertial oscillation may have a horizontal scale of the order of many times the local depth of water. Thus an island projecting from an otherwise uniform sea bed will give rise to a local, periodic disturbance near the island. It is shown that this disturbance may be resolved into two waves travelling in opposite senses round the island. If the particle orbits at large distances are circular, then only one of these waves has non-zero amplitude.In addition to the oscillatory motion, however, there is a steady d.c. streaming, or mass-transport velocity, whose magnitude is of order u2/σa where u denotes the magnitude of the oscillatory velocity at large distances, σ denotes the radian frequency, and a is the radius of the island. In this paper the profile of the streaming velocity is calculated for circular islands, with or without shoaling regions offshore. It is shown that resonance with the free modes trapped by the shoaling regions may greatly increase the streaming velocity. Viscosity (or horizontal mixing) also tends to increase the streaming velocity close to the shoreline.The conclusions are supported by some simple model experiments. It is suggested that such streaming may partly account for the observed pattern of currents near Bermuda.
TL;DR: A bathymetric chart of the Red Sea has been drawn from the most recent compilation of passage soundings combined with the results of detailed surveys as mentioned in this paper, and the chart can be found in Table 1.
Abstract: A new bathymetric chart of the Red Sea has been drawn from the most recent compilation of passage soundings combined with the results of detailed surveys. (Submitted as a written contribution after the meeting.)
TL;DR: The concentration of particulate organic carbon in the vicinity of Kavaratti Atoll is much greater than that of the surrounding sea as discussed by the authors. But, in the absence of an adequate standing crop of pyrotoplankton, the particulate matter may form an important source of energy to zooplanks.
Abstract: The concentration of particulate organic carbon in the vicinity of Kavaratti Atoll is
much greater than that of the surrounding sea. The particulate organic matter, which is
largely produced by the coral reef, amounts to about 20% of the total gross production of
tho reef community. It is suggested that, in the absence of an adequate standing crop of
phytoplankton, the particulate matter may form an important source of energy to zooplankton
in coral reef waters.
TL;DR: An analysis of the lipids of the deep sea jellyfish Atolla found an unusually large percentage of phthalic acid was found in the fatty acids of the saponifiable fraction.
Abstract: DURING an analysis of the lipids of the deep sea jellyfish Atolla, an unusually large percentage of phthalic acid was found in the fatty acids of the saponifiable fraction. The identification was based on gas liquid chromatographic (GLC) analysis on three columns (Table 1).
TL;DR: A 6-week Royal Society Expedition in the western Indian Ocean as discussed by the authors reported that 638 fishes were caught on drop lines worked chiefly at night at depths between 100 and 1000 m. The primary aim of the Expedition, to find specimens of the coelacanth Latimeria and thereby extend its known range, was not fulfilled.
Abstract: During a 6-week Royal Society Expedition in the western Indian Ocean 638 fishes were caught on drop lines worked chiefly at night at depths between 100 and 1000 m. Many of the species caught were rare or unrecorded from the area. The primary aim of the Expedition, to find specimens of the coelacanth Latimeria and thereby extend its known range, was not fulfilled. One teleost, the lutianid Etelis marshi , and a squaloid shark, Centrophorus sp., were particularly common, accounting for 60 % of the total catch; the remainder comprised 24 teleost and 11 elasmobranch species. Details are given of the itinerary, the fishing gear, fishing methods and the individual species caught, together with a brief discussion on the effect of depth, height of hooks above the sea floor and geographical position on the composition of the catches.
TL;DR: Transverse sand bodies of a new type from the continental shelf are commonly 2m high, 500m long and crescentic in plan view, and are transported at the present day by weak tidal currents (approximately 1 knot peak velocity near the surface) associated with wave induced oscillatory water movements of similar strength, rather than being formed near the shores at times of lower sea level.
Abstract: Transverse sand bodies of a new type from the continental shelf are commonly 2m high, 500m long and crescentic in plan view. They are believed to be transported at the present day by weak tidal currents (approximately 1 knot peak velocity near the surface) associated with wave induced oscillatory water movements of similar strength, rather than being formed near the shores at times of lower sea level.
TL;DR: A detailed gravity and bathymetric survey of the gulf and previous seismic reflection profiler traverses (Roberts and Stride, 1968) show the external zones of the orogen close westward paralleling the inner parts of the arc.
Journal Article•
TL;DR: A detailed description of a long range side-scan sonar, developed by the National Institute of Oceanography, has been written at the request of the International Hydrographic Bureau as mentioned in this paper.
Abstract: This brief description of a long range side-scan sonar, developed by the National Institute of Oceanography, has been written at the request of the International Hydrographic Bureau. A more detailed paper is being written at the moment by the team responsible for its development, which will describe the system more adequately.
TL;DR: A review of the geological and geophysical data over Rockall Plateau and the neighbouring deep ocean (unpublished results of D. G. R.) suggests that the plateau has many of the characteristics of continental structures and that it may be a continental fragment separated from Europe and Greenland during the break-up of Laurasia as suggested by Bullard, Everett and Smith as mentioned in this paper.
Abstract: ROCKALL PLATEAU (Fig. 1) is a well defined shoal area of depth less than 1,500 m, some 450 by 600 km in extent and separated from the continental shelf around Great Britain by the Rockall Trough, 2,700 m deep. In the NE corner of Rockall Plateau, Rockall Island is made of aegirine granite of Lower Eocene age1,2. A recent magnetic survey in the vicinity shows this to be part of a planated Tertiary volcanic centre3. A review of the geological and geophysical data over Rockall Plateau and the neighbouring deep ocean (unpublished results of D. G. R.) suggests that the plateau has many of the characteristics of continental structures and that it may be a continental fragment separated from Europe and Greenland during the break-up of Laurasia as suggested by Bullard, Everett and Smith4.
TL;DR: In this paper, a ship's log is described which works on the principle of electromagnetic induction, and the measuring head contains a coil with a vertical axis and is arranged so that voltages are picked up proportional to the two components of water flow past it.
Abstract: A ship's log is described which works on the principle of electromagnetic induction. The measuring head contains a coil with a vertical axis and is arranged so that voltages are picked up proportional to the two components of water flow past it. The electronic circuits are designed to give a true and stable zero by using a low-frequency squarewave energizing current. Laboratory tests show the output to be linearly related to water velocity. Because of the complicated flow patterns round a ship, the log must be calibrated in situ at sea. Calibration of the forward component meter follows the usual procedure and this meter is accurate to about ±0·1 knot or ± 1 per cent, whichever is greater. However, calibration of the athwartship component meter is difficult and time-consuming, and the sensitivity is dependent on forward speed. With care, it seems that an accuracy of ±0·2 knot or ± 10 per cent, whichever is greater, should be possible with this meter, but more experience of such calibrations is required. The paper is discussed on p. 319.
TL;DR: A mathematical model is proposed for more detailed population dynamics studies of plankton species in the Cochin Backwaters, taking E. commensalis as an example.
Abstract: A survey has been made of medusae found in plankton samples taken fortnightly over a period of a year at 2 fixed stations in the waters near Cochin, Kerala, India Twenty two species were identified, 8 of them were recorded for the first time in this region The 2 stations were found to be controlled by different hydrographical regimes; that at Aroor is entirely characterised by backwater conditions, with salinity afternating from fresh water to 32‰ S according to the monsoon cycle; the station at Fairway Buoy is also dominated by the monsoon cycle, with mixed, low-salinity (11 to 13‰) waters at the surface, and upwelled Arabian Sea water in the bottom layer during the Southwest monsoon Life cycles are discussed and the population dynamics of Eutima commensalis at Aroor are analysed A mathematical model is proposed for more detailed population dynamics studies of plankton species in the Cochin Backwaters, taking E commensalis as an example
01 Aug 1970
TL;DR: In this paper, changes in the temperature, salinity, pH and dissolved oxygen in relation to tidal rhythm were found to be well marked in the Zuari and Mandovi estuaries.
Abstract: Changes in the temperature, salinity, pH and dissolved oxygen in relation to tidal rhythm were found to be well marked in the Zuari and Mandovi estuaries. Seasonal differences in the hydrographical factors of the two estuaries are considerably influenced by the south-west monsoon. In the Zuari estuary, during the post-monsoon months, almost marine conditions seem to prevail with a little freshwater drainage whereas in the Mandovi estuary the freshwater discharge continues throughout the year which influences the environmental features. The two estuaries are rich in inorganic phosphate-P, the source of which in the Zuari estuary appears to be largely from the neritic waters whereas the input of inorganic phosphate-P in the Mandovi estuary seems to be influenced by the river-water. The rate of production was high in the samples from the two estuaries during the monsoon month. Changes in the rate of production induced by the tides corresponded with those in the inorganic phosphate-P, chlorophylla and the phytoplankton abundance. Probably the flora associated with the lower salinity dominates the crop of phytoplankton throughout the year in the Mandovi estuary whereas in the Zuari estuary the preponderance of the freshwater flora appears only during the monsoon month.
TL;DR: The lipids of five mesopelagic species of myctophid, two mesopelsic species of stomia-toid, and one epipelagic speciesof Macrorhamphosidae from the eastern-North Atlantic have been examined by thin-layer chromatography and their fatty acid compositions have been determined by gas-liquid chromatography.
Abstract: The lipids of five mesopelagic species of myctophid, two mesopelagic species of stomia-toid, and one epipelagic species of Macrorhamphosidae from the eastern-North Atlantic have been examined by thin-layer chromatography and their fatty acid compositions have been determined by gas-liquid chromatography.
TL;DR: Drei Arten der bispinosa-Gruppe der Gattung Conchoecia werden an Hand of Individuen aus der Region der Kanarischen Inseln hinsichtlich ihrer Morphologie and ihrers meristischen Merkmale untersucht.
Abstract: [Drei Arten der bispinosa-Gruppe der Gattung Conchoecia werden an Hand von Individuen aus der Region der Kanarischen Inseln hinsichtlich ihrer Morphologie und ihrer meristischen Merkmale untersucht. Individuen, welche Conchoecia haddoni zugerechnet werden, erwiesen sich als durchaus unterscheidbar von den anderen beiden Arten; sie gehoren zu einer kleinen Rasse. Von der Typ-Rasse standen fur Vergleichszwecke keine Vertreter zur Verfugung. C. bispinosa und C, secernenda sind sich morphologisch und hinsichtlich der meristischen Charakteristika sehr ahnlich. Bis jedoch nachgewiesen werden kann, das Postmaturations-Hautungen oder diskontinuierliches Zwischenhautungswachstum bei Conchoecia-Arten vorkommen, werden diese beiden Populationsgruppen mit nichtuberlappenden Grosenklassen und teilweise uberlappenden geographischen Verbreitungsarealen als verschiedene Spezies angesehen., Drei Arten der bispinosa-Gruppe der Gattung Conchoecia werden an Hand von Individuen aus der Region der Kanarischen Inseln hinsichtlich ihrer Morphologie und ihrer meristischen Merkmale untersucht. Individuen, welche Conchoecia haddoni zugerechnet werden, erwiesen sich als durchaus unterscheidbar von den anderen beiden Arten; sie gehoren zu einer kleinen Rasse. Von der Typ-Rasse standen fur Vergleichszwecke keine Vertreter zur Verfugung. C. bispinosa und C, secernenda sind sich morphologisch und hinsichtlich der meristischen Charakteristika sehr ahnlich. Bis jedoch nachgewiesen werden kann, das Postmaturations-Hautungen oder diskontinuierliches Zwischenhautungswachstum bei Conchoecia-Arten vorkommen, werden diese beiden Populationsgruppen mit nichtuberlappenden Grosenklassen und teilweise uberlappenden geographischen Verbreitungsarealen als verschiedene Spezies angesehen.]