Showing papers by "National Institute of Oceanography, India published in 1972"
202 citations
TL;DR: In this article, side scan sonar methods are used to increase knowledge of the detailed topography of the bed of the ocean: a new long range device, which can produce sonographs at a range of 22 km, has located a tectonic plate boundary.
Abstract: Side scan sonar methods are increasing knowledge of the detailed topography of the bed of the ocean: a new long range device, which can produce sonographs at a range of 22 km, has located a tectonic plate boundary. Small scale fluctuations in the vertical profiles of temperature and salinity are exciting oceanographers, meteorologists and fluid dynamicists alike.
132 citations
TL;DR: The wide adaptability of phytoplankton to changes in salinity corresponds to the conditions brought about by the monsoon system along the southwest coast of India, where large dilutions are associated with the enrichment of water with nutrients.
Abstract: Several species of phytoplankton were grown in unialgal, but not bacteria-free, cultures. These clones when exposed to varying salinities, from 5 to 35‰, showed a marked increase in their rates of photosynthesis at low salinities. The optimum requirement of salinity, however, varied in different species. Observations on the relative abundance of phytoplankton in an estuary, where the salinity changes were fairly large, confirmed that, within limits, waters with low salinities support a greater abundance of phytoplankton in nature. The wide adaptability of phytoplankton to changes in salinity corresponds to the conditions brought about by the monsoon system along the southwest coast of India, where large dilutions are associated with the enrichment of water with nutrients.
105 citations
TL;DR: On the SOND cruise of R.R.S. 'Discovery' in 1965, a day and a night series of horizontal hauls were made with a modified Indian Ocean Standard Net (N113 H) fitted with a catch dividing bucket (C.D.B.).
Abstract: On the SOND Cruise of R.R.S. 'Discovery' in 1965 a day and a night series of horizontal hauls were made with a modified Indian Ocean Standard Net (N113 H) fitted with a catch dividing bucket (C.D.B.). The hauls were of 1 h duration, made at approximately 50 m depth intervals from 960 to 40 m, at a position off Fuerteventura in the Canary Islands. This paper is one of a series by various authors on the vertical distributions of the animal groups sampled (Angel, 1969; Clarke, 1969 a; Baker, 1970; Badcock, 1970; Foxton, 1970a, b). Details of the cruise and of the hydrology of the area are given by Currie, Boden & Kampa (1969), and Foxton (1969) gave details of the sampling methods.
87 citations
TL;DR: At both beaches, the most stable conditions were reached in the pre-monsoon months when the greatest number of species occurred and when there was marked zonation.
Abstract: Changes during one year in the fauna of two beaches in south India are described in relation to the nutrient content of the water and sand, and the physical changes brought about by the south-west monsoon. At both beaches, the most stable conditions were reached in the pre-monsoon months when the greatest number of species occurred and when there was marked zonation. During the monsoon, erosion took place and only actively migrating species remained to form a permanent element of the beach fauna. Data on population density and biomass indicate markedly seasonal recruitment and rapid growth of individual species, most of which are suspension feeders.
87 citations
TL;DR: In Loch Ness, the surge is produced by the stress of the wind on the water surface, which causes a flow of near-surface water to one end of the Loch and a depression of the thermocline at that end as discussed by the authors.
Abstract: THE large temperature changes which occur at depth in Loch Ness are caused by an internal seiche or standing wave1,2, which develops a pronounced front or surge like a tidal bore and is sometimes followed by a periodic oscillation of the isotherms. The surge is produced by the stress of the wind on the water surface2,3, which causes a flow of near-surface water to one end of the Loch and a depression of the thermocline at that end. When the wind falls, the tendency of the thermocline to recover a level position initiates the surge, which is often over 10 m in height. The following wave train, when it occurs, is of comparable height and contains waves about 1 km long. No effects are seen, or are expected to be seen, at the surface. In calm weather the surge progresses up and down the Loch for more than a week, during which time it travels more than 200 km (refs. 2 and 4).
71 citations
TL;DR: In this paper, the authors used a modified Indian Ocean Standard Net (N113H) on the R.R.S. 'Discovery' SOND cruise of 1965.
Abstract: This paper is the third of four dealing with the calanoid copepods taken with a modified Indian Ocean Standard Net (N113H) on the R.R.S. 'Discovery' SOND cruise of 1965. Details of the cruise are given by Currie, Boden & Kampa (1969) and the sampling methods used in the N113 H series are described by Foxton (1969) and by Angel (1969).
68 citations
62 citations
TL;DR: In this article, a class of inviscid irrotational flows which satisfy the conditions at a time-dependent free surface exactly were investigated. But the results were limited to the elliptical and hyperbolic cases.
Abstract: Attention is drawn to a class of inviscid irrotational flows which satisfy the conditions at a time-dependent free surface exactly. The flows are related to the ellipsoids of Dirichlet (1860).Depending on a parameter P, the cross-section may take the form of a variable ellipse (P 0) or a pair of parallel lines (P = 0). The elliptical case was investigated both theoretically and experimentally by Taylor (1960). The hyperbolic case (P > 0) is remarkable in that the flow develops a singularity when the angle between the asymptotes approaches a right-angle. It is suggested that this solution represents a possible instability near the crest of a standing gravity wave of large amplitude.In the intermediate case (P = 0) the solution describes an open-channel flow in which the fluid filaments are stretched uniformly in a horizontal direction. The latter flow is demonstrated experimentally.
59 citations
TL;DR: In this paper, a continuous east-west reflector has been observed with long range side-scan sonar, extending along the Azores-Gibraltar Ridge from Santa Maria Is. to a point 400 km to the east.
Abstract: A continuous east–west reflector has been observed with long range side-scan sonar, extending along the Azores–Gibraltar Ridge from Santa Maria Is. to a point 400 km to the east. From the continuity, narrowness and straightness of the feature, from the evidence of seismic reflexion profiles crossing it and from other published geophysical evidence about the Azores–Gibraltar Ridge, the reflector is interpreted as a transcurrent fault.
56 citations
TL;DR: The caloric value of detritus, calculated from protein, carbohydrate and lipid fractions and also from total carbon, indicates that sedimenteddetritus does not have a high nutritional value, however, being a readily available material, its entry into the food chain seems to increase the efficiency of energy transfer from one trophic level to another.
Abstract: Organic detritus of the Cochin Backwater (India) is largely composed of fine silt and sand particles around which organic matter adheres and forms aggregates. In addition to plankton, large quantities of benthic algae, rooted plants, animal matter, suspended soft mud and the material brought down by the rivers and land runoff constitute the main sources of detritus. Detritus sedimentation in the estuary attains its maximum from April to June. Detritus forms a major portion of seston, while phytoplankton productivity constitutes 0.1 to 1.0% of settled detritus. Detrital pigments include degraded chlorophyll (phaeophytin), which has a marked seasonal variation; detrital carbon, phosphorus and nitrogen show little change during the year. The caloric value of detritus, calculated from protein, carbohydrate and lipid fractions and also from total carbon, indicates that sedimented detritus does not have a high nutritional value. However, being a readily available material, its entry into the food chain seems to increase the efficiency of energy transfer from one trophic level to another.
TL;DR: In this article, a long series of sea-level observations at Brest, extending from 1711 to the mid-20th century, are analysed by modern methods to search for secular trends in the admittances of the oceanic tides to the gravitational potential, already suggested by results from St Helena.
Abstract: Summary Long series of sea-level observations at Brest, extending from 1711 to the mid-20th century, are analysed by modern methods to search for secular trends in the admittances of the oceanic tides to the gravitational potential, already suggested by results from St Helena. Special attention is paid to the editing and analysis of the historic series of observations of High and Low Waters published in Lalande's Astronomie. The results not only confirm an increase in diurnal phase lead of some 3 degrees per century, but show a smaller but more significant decrease in semi-diurnal amplitude, about 1 per cent per century, in keeping with some results of Doodson from shorter records from the Bay of Fundy. The possible effects of modern harbour developments are discussed, and found to be probably insignificant, but the question whether the trends are truly oceanic or due to local coastal changes remains open.
TL;DR: The material provides evidence that four species of cephalopod are at least partially demersal and suggests a means by which the tapeworm Phyllobothrium could pass from its secondary to its primary host.
Abstract: Twenty-four out of 240 fishes caught by bottom lines at 366–3333 m had something in their stomachs Stomach contents included parts of cephalopods, fish, cetaceans and bottom-living invertebrates, thin rubber sheet and terrestrial mammal bones The material provides evidence that four species of cephalopod are at least partially demersal and suggests a means by which the tapeworm Phyllobothrium could pass from its secondary to its primary hostDuring the five biological cruises of RRS ‘Discovery’ between 1967 and 1971 a total of 31 bottom lines with 1483 hooks were fished in depths of water between 366 and 3333 m The stomachs of the 240 fish caught were examined and 216 (90%) proved to be empty The high incidence of empty stomachs is thought to be due to frequent loss of food during the ascent from great depths and accounts for our poor knowledge of the feeding habits of demersal fish living at depths exceeding 400 mThe present collection of food from 25 stomachs (24 from ‘Discovery’ collections and one from a fish caught by Mr G R Forster from R V ‘Sarsia’) of fish belonging to 11 species (Table 1) probably gives little indication of the usual diet of the fish concerned, but its nature prompts some useful speculation and the rarity of such observations justifies placing them on record (Bigelow & Schroeder, 1948; Marshall, 1954)All the fish were caught on lines which lay on the bottom for several hours and it is our firm belief that they were hooked while on or very near the bottom
TL;DR: The biology of two species of Donax, D. incarnatus Gmelin and D. spiculum Reeve on two beaches in south west India is described, and data on growth, mortality and production are presented.
Abstract: The biology of two species of Donax, D. incarnatus Gmelin and D. spiculum Reeve on two beaches in south west India is described. Two year groups of D. incarnatus were present on both beaches, from settlements during the monsoon period in 1967 and 1968. At Shertallai, both groups were studied through the year, and data on growth, mortality and production are presented. At Cochin, the rate of growth was slower and the maximum size attained smaller, but mortality during the early monsoon precluded study of D. incarnatus through a full year. D. spiculum occurred at Cochin mainly during the pre-monsoon period, and at Shertallai during the post-monsoon. The species has a shorter life-span than D. incarnatus, but its irregular occurrence did not allow detailed production estimates.
TL;DR: Observations on the size-frequency of samples for Shertallai suggest that there were two main periods of recruitment, one in the pre-monsoon, months of February and March, and one during the monsoon, although there may have been some recruitment throught the year.
Abstract: The mole crab Emerita holthuisi Sankolli occurred on two beaches, at Shertallai and at Cochin, in southwest India. Observations on the size-frequency of samples for Shertallai suggest that there were two main periods of recruitment, one in the pre-monsoon,months of February and March, and one during the monsoon, although there may have been some recruitment throught the year. At Cochin, E. holthuisi was present in the pre-monsoon period, but disappeared from the beach during the monsoon.
TL;DR: It would appear that wax esters can function as energy reserves and are laid down by animals living in areas of low food density, where energy conservation is important, partly to achieve a more neutral buoyancy.
Abstract: The lipids of 2 species and 1 group of copepods, 4 species of euphausiids, 2 species of mysids, and 6 species of decapods, taken from different depths in the North-eastern Atlantic Ocean and Western Mediterranean Sea, have been analysed specifically for their wax ester content The mid-water animals living below 500 m contained large amounts of wax ester (30 to 80% total lipid), while those animals living in the upper 600 to 700 m or on the sea floor had only small wax ester fractions (5 to 10% total lipid) It is suggested that the wax esters are laid down by those animals living in areas of low food density, where energy conservation is important, partly to achieve a more neutral buoyancy In addition, it would appear that wax esters can function as energy reserves
TL;DR: It is made clear that adequate sampling in space and time is required along the Continental Shelf of the Indian Ocean in order to obtain more comprehensive information on this group of species.
Abstract: Cladocera of the Indian Ocean have been studied, on the basis of samples collected during the International Indian Ocean Expedition (IIOE). Out of a total of 1927 samples, 552 contained Cladocera. Although the distribution of this group is mainly coastal, one species, Evadne tergestina, has been found in oceanic waters also, where it may establish seasonal populations. Evadne spinifera was recorded off the Australian and South African coasts in the southern hemisphere, and in the Northeastern part of the Arabian Sea coastal waters in the northern hemisphere. Podon polyphemoides was reported from a single station in South African waters. Penilia avirostris was found in coastal waters throughout the Indian Ocean. Short-term distribution patterns of E. tergestina and P. avirostris are discussed. The possible value of this group as food for pelagic fishes has been indicated. This work makes clear that adequate sampling in space and time is required along the Continental Shelf of the Indian Ocean in order to obtain more comprehensive information on this group.
TL;DR: A midwater pigment peak is explicable in terms of pigment accessibility and requirement for protective coloration, and the significance of the pigments is discussed.
Abstract: Analysis of the carotenoid pigment and lipid concentrations of groups of the smaller zooplankton organisms from different depths has suggested a midwater maximum for carotenoid concentrations and a slight depth-related increase in lipid content. Similar analysis of seventeen species of euphausiid has not indicated similar trends, but has shown a close relationship between size and pigment content in all species other than those of Stylocheiron, which have significantly lower pigment concentrations. Comparisons of the data of Fisher, Kon & Thompson (1964) on the pigment and lipid concentrations of copepods with the known depth ranges of the various species have suggested a midwater maximum in pigment concentrations, but no consistent trends in the lipid concentrations. A midwater pigment peak is explicable in terms of pigment accessibility and requirement for protective coloration, and the significance of the pigments is discussed.
TL;DR: In this article, a detailed study of the eastern margin of the Rockall Plateau using topographic and seismic profiler data has revealed two large slumps on the upper parts of the slope.
TL;DR: The major burst of interest came in the twenty years 1890-1909, when first Claus and then G. W. Muller published series of papers describing the majority of the present species.
Abstract: Brady's (1880) Challenger report mentioned only three species of planktonic ostracods, all halocyprids. At that time only 10 halocyprid species were known and only 14 papers had been written on the group. The major burst of interest came in the twenty years 1890–1909, when first Claus and then G. W. Muller published series of papers describing the majority of the present species. Table 1 shows the wax and wane in the numbers of papers published and the species described by decades since 1849 when Dana described the first species. The table clearly shows the recent upsurge of interest in the group. Many of the papers include only passing mention of planktonic ostracods, and so this review attempts to assemble all these scattered references so that the ecological importance of the group can be appreciated and further research requirements become clearer
TL;DR: According to YONGE (1960) "an atoll raised to the surface in the midst of oceanic waters may be described as a large scale experiment in nature" as discussed by the authors.
Abstract: According to YONGE (1960) "an atoll raised to the surface in the midst of
oceanic waters may be described as a large scale experiment in nature". Earlier
studies have contributed to an understanding of primary production of atolls
and coral reefs of the Pacific and Atlantic Oceans (SARGENTan d AUSTIN,
1949, 1954; ODUMa nd ODUM1, 955; KOHNa nd HELBRICH1, 957; ODUMB, URKHOLDER
and RIVERO1, 959 ; GORDOaNn d KELLY1, 962). Comparable information
on the atolls of the Indian Ocean has been completely lacking. Since GARDINER
(1903-1906) published his classical work on the Maldive and Laccadive
Archipelagoes, practically no knowledge has been added to the atolls of the
Laccadives
TL;DR: Observations of the currents close to the sea floor below the Mediterranean outflow in the Gulf of Cadiz have discovered evidence of a cloud of sediment which seems to come from the Mediterranean water itself.
Abstract: DURING observations of the currents close to the sea floor below the Mediterranean outflow in the Gulf of Cadiz, we have discovered evidence of a cloud of sediment which seems to come from the Mediterranean water itself.
TL;DR: The photosensitizing effect of some porphyrins prevents their accumulation in the epidermal layers of animals living in well-illuminated environments, unless the porphrin are accompanied by some other screening pigment or the animal can retreat into a dark micro-environment.
Abstract: THE photosensitizing effect of some porphyrins prevents their accumulation in the epidermal layers of animals living in well-illuminated environments, unless the porphyrins are accompanied by some other screening pigment or the animal can retreat into a dark micro-environment1–4. Thus some shallow water marine annelid worms contain considerable quantities of porphyrins in their tissues, but are tubicolous or burrowing in habit5. They are difficult to maintain in the light in the laboratory, often exhibiting symptoms which could be said to resemble those of human porphyria6. Beneath the immediate surface layers of the ocean, however, light intensity is rapidly reduced to very low values, and the deep sea is in almost total darkness. Kennedy7 has noted that the low light intensities in which many marine animals live would prevent the appearance of porphyria symptoms leading to illness and death in the human subject. In these conditions, the accumulation of porphyrins is no longer hazardous, and they may be used like any other pigment for purposes of tissue coloration. The identification of free porphyrins as the source of the general body coloration of certain deep-sea medusae supports this view.
TL;DR: The luminescent material emitted from the post-cleithral organ of searsid fishes is in the form of granule-packed cells, and a partially purified extract may be prepared which shows some of the properties to be expected from a photoprotein.
Abstract: The luminescent material emitted from the post-cleithral organ of searsid fishes is in the form of granule-packed cells. From this material a partially purified extract may be prepared which shows some of the properties to be expected from a photoprotein. The purified material luminesces on treatment with hydrogen peroxide and, specifically, ferrous iron. The properties of the luminescent system appear similar to those of material isolated from the luminous polychaete Chaetopterus.
TL;DR: In this paper, narrow-beam and conventional deep-sea echograms from the Mediterranean Ridge are shown at the same horizontal and vertical scales and the narrowbeam profiles give a far more accurate delineation of the blocky relief of this tectonic feature.
TL;DR: A blue carotenoprotein containing astaxanthin as the prosthetic group, was purified from the copepod, Labidocera acutifrons and shows it to be a simple one, deficient in tyrosine, containing three astrixanthin molecules per apoprotein unit.
Abstract: 1. 1. A blue carotenoprotein containing astaxanthin as the prosthetic group, was purified from the copepod, Labidocera acutifrons . 2. 2. The protein has a molecular size of about 720,000, as estimated by gel filtration. The apoprotein has a molecular size of about 26,000 and separates into two components on electrophoresis. 3. 3. Analyses of the protein shows it to be a simple one, deficient in tyrosine, containing three astaxanthin molecules per apoprotein unit. 4. 4. The characteristics of the protein are compared with those of the decapod crustacean carotenoproteins and other polyene-binding proteins of known composition. 5. 5. The mode of binding of the prosthetic group is discussed.
DOI•
29 Jan 1972TL;DR: In this article, the results of calculations of the parameters in the 50-year storm are presented, based on extreme wind data and on instrumental wave measurements, and are combined in two maps, one of extreme wave height and the other of the corresponding wave period.
Abstract: Information on extreme wave conditions is needed in the design of offshore structures. This paper present the results of calculations of the parameters in the 50-year storm; the work has been based on extreme wind data and on instrumental wave measurements. The results are complementary, and are combined in two maps, one of extreme wave height and the other of the corresponding wave period.
TL;DR: A number of records of sea bed pressure, with durations from 10 to 32 days, have been taken near the edge of the northwest European shelf with the instrument capsule described by Collar and Spencer (1970).
TL;DR: Abundance of specific phytoplanktonic elements, consisting mainly of diatoms, in space and time, characterises the waters of the central west coast of India, indicating a clear succession of species.
Abstract: Distribution of chlorophyll pigments, carotenoids and abundance of phytoplankton in relation to certain environmental factors of the nearshore waters off the central west coast of India (latitudes 15°30′ to 18°30′N) were studied monthly at 7 stations during 1970/1971. Changes in the hydrographical factors and the biological processes occurring in the region during different months appear to be influenced by the pattern of upwelling along the northern and southern parts of the west coast of India. The pigment concentration shows a marked decrease in October, but is followed by a slow but steady rise, which reaches its maximum in April/May. A slightly smaller maximum is noticed in December/January. The composition of various chlorophyll pigments and carotenoids indicated the physiological state of phytoplankton populations during different months in the region investigated. Abundance of specific phytoplanktonic elements, consisting mainly of diatoms, in space and time, characterises the waters of the central west coast of India, indicating a clear succession of species.
TL;DR: Using solar energy as a source of illumination, photosynthesis in 11 species of marine plankton algae was studied as a function of light intensity, and the photosynthetic response shown by the different organisms was strikingly similar, which signifies that they are capable of much chromatic adaptation.
Abstract: Using solar energy as a source of illumination, photosynthesis in 11 species of marine plankton algae was studied as a function of light intensity. From the photosynthesis-light curve for each organism, the saturation points (I
k
) in different organisms were determined. Among the diatoms and flagellates, the highest I
k
(saturation point) values were found in Rhizosolenia styliformis and Dinophysis miles respectively. When the organisms were exposed to a portion of the visible spectrum starting from 700 mμ, the photosynthesis was found to be related to the radiant energy. The missing portions of the spectrum produced no significant change in the rate of photosynthesis. The photosynthetic response shown by the different organisms was strikingly similar, which signifies that, despite the qualitative dissimilarities which the organisms may possess in their pigment composition, they are capable of much chromatic adaptation.