Showing papers by "Woods Hole Oceanographic Institution published in 1975"
01 Jan 1975
TL;DR: The methods suffice for the most fastidious algae now routinely cultivable, and simplifications indicated for less demanding species are easily made; for example, omission of silicate for plants other than diatoms.
Abstract: These pages describe relatively simple and reliable methods for the culture of marine phytoplankton species useful for feeding marine invertebrates. The methods suffice for the most fastidious algae now routinely cultivable, and simplifications indicated for less demanding species are easily made; for example, omission of silicate for plants other than diatoms. Certain modifications of techniques, ancillary methods, and precautions will be treated briefly because questions often arise concerning them, but documentation will be minimal and hopefully restricted to publications readily available.
5,000 citations
TL;DR: In this paper, the authors studied the geophysical beta-effect of two-dimensional eddies in a homogeneous fluid at large Reynolds number, and showed that when the energy is intermittent in space, the cascade is halted simply by the spreading of energy about space, and then the end state of a zonal flow is probably not achieved.
Abstract: Two-dimensional eddies in a homogeneous fluid at large Reynolds number, if closely packed, are known to evolve towards larger scales. In the presence of a restoring force, the geophysical beta-effect, this cascade produces a field of waves without loss of energy, and the turbulent migration of the dominant scale nearly ceases at a wavenumber kβ = (β/2U)½ independent of the initial conditions other than U, the r.m.s. particle speed, and β, the northward gradient of the Coriolis frequency.The conversion of turbulence into waves yields, in addition, more narrowly peaked wavenumber spectra and less fine-structure in the spatial maps, while smoothly distributing the energy about physical space.The theory is discussed, using known integral constraints and similarity solutions, model equations, weak-interaction wave theory (which provides the terminus for the cascade) and other linearized instability theory. Computer experiments with both finite-difference and spectral codes are reported. The central quantity is the cascade rate, defined as
\[
T = 2\int_0^{\infty} kF(k)dk/U^3\langle k\rangle ,
\]
where F is the nonlinear transfer spectrum and 〈k〉 the mean wavenumber of the energy spectrum. (In unforced inviscid flow T is simply U−1d〈k〉−1/dt, or the rate at which the dominant scale expands in time t.) T is shown to have a mean value of 3·0 × 10−2 for pure two-dimensional turbulence, but this decreases by a factor of five at the transition to wave motion. We infer from weak-interaction theory even smaller values for k [Lt ] kβ.After passing through a state of propagating waves, the homogeneous cascade tends towards a flow of alternating zonal jets which, we suggest, are almost perfectly steady. When the energy is intermittent in space, however, model equations show that the cascade is halted simply by the spreading of energy about space, and then the end state of a zonal flow is probably not achieved.The geophysical application is that the cascade of pure turbulence to large scales is defeated by wave propagation, helping to explain why the energy-containing eddies in the ocean and atmosphere, though significantly nonlinear, fail to reach the size of their respective domains, and are much smaller. For typical ocean flows, . In addition the cascade generates, by itself, zonal flow (or more generally, flow along geostrophic contours).
1,124 citations
TL;DR: In this article, it is suggested that polycyclic aromatic hydrocarbons are formed in natural fires, are dispersed and mixed by air transport and eventually deposited into surface sediments.
478 citations
TL;DR: The availability of inorganic nutrients is usually attributed to the proximity of fresh-water runoff or to coastal upwelling and deep water advection1,2,3 as mentioned in this paper.
Abstract: SHALLOW near-shore ocean waters support high primary production because of the availability of inorganic nutrients. The availability is usually attributed to the proximity of fresh-water runoff or to coastal upwelling and deep water advection1,2.
276 citations
TL;DR: The evidence suggests that these hydrocarbons are formed in natural fires, are dispersed and mixed by air transport, and are eventually deposited into surface sediments.
Abstract: Soils and recent marine sediments contain a complex polycyclic aromatic hydrocarbon assemblage. There is a high degree of similarity in the molecular weight distribution of the many series of alkyl homologs of these aromatic hydrocarbons, and this distribution varies little over a wide range of depositional environments. The evidence suggests that these hydrocarbons are formed in natural fires, are dispersed and mixed by air transport, and are eventually deposited into surface sediments. The analytical, geochemical, and environmental implications of these findings are discussed.
257 citations
TL;DR: The effect of the initial substrate surface condition, as indicated by the critical surface tension for wetting, on the rate of attachment of marine bacteria to a variety of solid surfaces has been measured and their significance to the control of microbiological slime film formation is discussed.
Abstract: The effect of the initial substrate surface condition, as indicated by the critical surface tension for wetting, on the rate of attachment of marine bacteria to a variety of solid surfaces has been measured. The techniques used to determine the number of bacteria attached per unit surface area were a lipopolysaccharide test utilizing Limulus lysate and direct examination of the surface by scanning electron microscopy. The results obtained by the two techniques are compared and their significance to the control of microbiological slime film formation (microfouling) is discussed.
255 citations
TL;DR: The distribution of benthic megafauna on the Gay Head-Bermuda transect has been studied in this paper for a series of dives at 1300 and 1800 m.
200 citations
TL;DR: In this article, Cushman et al. discuss the biostratigraphy and biogeography of the mid-way-type foraminiferal assemblages.
195 citations
TL;DR: Sedimentation on the Amazon continental margin occurred in two distinct patterns during the Quaternary Period as discussed by the authors : during interglacials, when sea level was high (as at present), most of the sediment contributed by the Amazon River was deposited near the river mouth, then transported northwest along the innermost shelf by longshore currents.
Abstract: Sedimentation on the Amazon continental margin occurred in two distinct patterns during the Quaternary Period. During interglacials, when sea level was high (as at present), most of the sediment contributed by the Amazon River was deposited near the river mouth, then transported northwest along the innermost shelf by longshore currents. Apparently, little Amazon sediment escaped the nearshore environment. As sea level fell in response to glacial advance, the sedimentation pattern remained roughly similar, resulting in construction of an extensive prograding shoreline. Once the sea fell more than −60 to −80 m relative to present sea level, however, most Amazon sediment was channeled directly to the deep sea. Shoreline accretion stopped, but prograded sediments were preserved as a mud wedge that presently occupies the inner shelf seaward of the Amazon River. This model also explains the accumulation of large quantities of arkosic sands throughout the western Equatorial Atlantic deep sea during Pleistocene glacial epochs. These arkosic sediments appear to have been derived mostly from the Andes Mountains via the Amazon River.
176 citations
TL;DR: The distribution of coccolithophores was studied in the neritic environment along the western margin of the Pacific Ocean and the diversity of species in these marginal seas was much lower than in the pelagic environment, although no species was found to be exclusively neritic.
Abstract: The distribution of coccolithophores was studied in the neritic environment along the western margin of the Pacific Ocean: the Inland Sea of Seto, Yellow Sea, East China Sea, South China Sea, Java Sea, Timor Sea, Arafura Sea and Gulf of Carpentaria. The coccolithophore community in the Red Sea was also studied for comparison with the Pacific marginal seas. With minor exceptions, the coccolithophore communities were very similar throughout the neritic areas investigated, but differed completely from the pelagic community in three aspects. Firstly, almost all neritic coccolithophores, regardless of species, suffered various degrees and forms of malformation with relation to the morphology of their coccoliths, while such malformation was rare in the pelagic population. Nitrogen deficiency may cause such malformation. Secondly, the diversity of species in these marginal seas was much lower than in the pelagic environment, although no species was found to be exclusively neritic. Emiliania huxleyi, usually ubiquitous in oceanic areas and in various neritic environments of higher latitudes, was scarce, while Gephyrocapsa oceanica dominated the flora throughout the studied areas. Finally, the horizontal and vertical distributions of the neritic populations were sporadic compared to those of the rather uniform pelagic environments.
171 citations
TL;DR: The final effluent from the system is virtually free of inorganic nitrogen and is incapable of supporting further growth of marine life or of contributing to eutrophication of the receiving waters.
TL;DR: For example, 30,750 line-km of geophysical traverses (seismic reflection and refraction, magnetics, and gravity) were made in the Gulf of Guinea and vicinity aboard R/V Atlantis II during 1972 and 1973 as part of the International Decade of Ocean Exploration program.
Abstract: About 30,750 line-km of geophysical traverses (seismic reflection and refraction, magnetics, and gravity) were made in the Gulf of Guinea and vicinity aboard R/V Atlantis II during 1972 and 1973 as part of the International Decade of Ocean Exploration program. These traverses, supplemented by about 50,000 line-km of previous ones by other ships, provide a basis for mapping and understanding the geologic structure, history, and origin of the region. The deep indentation of the outline of western Africa is paralleled by a similar bend of the Mid-Atlantic Ridge and by the prominent bulge of northeastern Brazil. These sharp bends are the result of left-lateral offsets by many transform faults in a belt of equatorial fracture zones. Some of the fracture zones continue eastward and intersect the entire length of the east-west coast of the Gulf of Guinea and penetrate the continent at the Benue trough or graben. The valleys of the fracture zones have been sites of sediment deposition, whereas the ridges have served as dams that force the sediment to move westward. Where enormous quantities of sediment have been delivered to the ocean by the Niger-Benue Rivers, a large delta has deeply buried the irregular topography of the fracture zones. In this entire belt of fractured ocean floor the structure, physiography, and stratigraphy have been controlled by lateral movement, or translation, of the ocean floor with respect to the continent. In contrast, the regions southeast and northwest of the belt of equatorial fractures have fewer large fracture zones, smoother topography, and simpler sediment wedges. These two regions owe their origin to simple divergence during sea-floor spreading, when new oceanic basement added at the Mid-Atlantic Ridge increased the distances between the African continent, the Mid-Atlantic Ridge, and the American continents. Deposition of sediments along the margins of the originally narrow Atlantic Ocean was dominated early by coarse-grained and largely nonmarine sediments. South of the Gulf of Guinea these deposits were followed by evaporites as products of restricted water circulation in a long narrow arm of the ocean. There was little flow of water across the equator because of the sliding-v lve nature of the region of translation between the two regions of divergence. As spreading continued, the ocean widened, and thick prisms of marine sediments were deposited on the continental margins. Large deltas in western Africa first began at the south, with the now submerged deltas of the Orange and the Congo Rivers being chiefly Mesozoic in age and having no present coastal projection. The Niger delta farther north is mostly Cenozoic in age. Petroleum prospects appear to be far greater in the Niger delta and the region of divergence south of it than in the entire region west of the delta. The favorable continental margin contains thicker sediments, large ancient and modern deltas, and salt and mud diapirs. End_Page 2209------------------------------
TL;DR: In this article, the authors suggest that an in-situ titration of some of the alkalinity by protons derived from the redox changes associated with organic decomposition of organic matter may explain an apparent excess of calcium in seawater.
TL;DR: In the Deep Sea Drilling Project (DSDP) samples of interstitial solutions of deeply buried marine sediments throughout the World Ocean have been obtained and analyzed as discussed by the authors, and these changes can be grouped into a few consistent patterns that facilitate identification of the diagenetic reactions occurring in the sediments.
TL;DR: In this paper, the GATE Equatorial Oceanographic Experiment (GATE) was used to observe the South Equatorial Current and the Equatorial Undercurrent with time scales of 2-3 weeks.
Abstract: Observations from the GATE Equatorial Oceanographic Experiment are presented. They reveal large scale meandering of the westward flowing South Equatorial Current and of the eastward flowing Equatorial Undercurrent with time scales of 2–3 weeks. Meandering of the flow pattern was found to be related to corresponding displacements of the high salinity core of the undercurrent. The observations tend to support the assumption of a long wave propagating westward with a phase speed of 2.3 m s−1 and a wavelength of 3,200 km. A possible explanation may be given in terms of unstable waves caused by large scale horizontal shear in the Equatorial Current System.
TL;DR: In this paper, the authors studied the adsorption of cobalt on synthetic hydrous manganese dioxide and showed that cobalt adsorbed increased sharply at pH 6, a significantly lower pH than that required for significant hydrolysis of Co(II) or precipitation of Co (OH) 2 (S) in bulk solution.
TL;DR: The first manned submersible studies of a mid-ocean ridge were conducted by the French Submersible Archimede in 1973 and by the American Submergence Unit (USU) during the summer of 1974 as mentioned in this paper.
Abstract: es associated with genesis of new oceanic crust. A small area on the Mid-Atlantic Ridge centered at about 36050'N was selected for detailed study on the basis of scientific and logistic criteria (Fig. 1). More than 25 cruises were made to the area by surface ships from the United States, France, Canada, and England, culminating in the first manned submersible studies of a mid-ocean ridge by the French submersible Archimede in 1973, and by Archimede, Cyana, and the American submersible Alvin during the summer of 1974. The regional setting of the dive site was established by narrow-beam echo sounding, dredging, side-scan sonar and deep-tow
TL;DR: Approximately 25 percent of the dissolved silica carried by the Amazon River is depleted through diatom production in the inner estuary, and many frustules apparently are transported landward into the river system, where they deposit in dunes and layers on and within mud and sand bars.
Abstract: Approximately 25 percent of the dissolved silica carried by the Amazon River is depleted through diatom production in the inner estuary. Annual production of opaline frustules is estimated to be 15 million tons. However, few diatoms accumulate in modern shelf sediments and chemical recycling appears to be slight. Instead, many frustules apparently are transported landward into the river system, where they deposit in dunes and layers on and within mud and sand bars.
TL;DR: Data indicate post-larvae of planktotrophic species have fewer arm segments than newly-hatched viviparous young, supporting the hypothesis that large size of juveniles is characteristic and selectively advantageous for vivIParous ophiuroids.
Abstract: There is only limited information on ophiuroid developmental patterns, larvae being known for only 4% of the 2000 living ophiuroids. Three modes of development are distinguished (planktotrophic, direct, abbreviated) on the basis of egg size and number, larval form and life span, and post-larval size. This generalization is applied to an analysis of the larval form(s) of deep-sea ophiuroids and the ancestral ophiuroid larva. Quantitative information on rate of development and reproductive period, which has been lacking for viviparous ophiuroids, is presented for Axiognathus ( = Amphipholis) squamatus on the basis of original size-frequency data. Reproduction is seasonal in the population studied and development to metamorphosis takes no longer than for planktotrophic species though the brooding period ranges from 3 to 7 months. Additional data indicate post-larvae of planktotrophic species have fewer arm segments than newly-hatched viviparous young, supporting the hypothesis that large size of juveniles is characteristic and selectively advantageous for viviparous ophiuroids.
01 Jan 1975
TL;DR: In this article, a 17,000 km of continuous gravity, magnetic, and seismic-reflection profiles were recorded to determine the structure of the continental margin from Cape St. Francis to Walvis Ridge, and of the adjacent Agulhas and Cape deep-ocean basins.
Abstract: Approximately 17,000 km of continuous gravity, magnetic, and seismic-reflection profiles were recorded to determine the structure of the continental margin from Cape St. Francis to Walvis Ridge, and of the adjacent Agulhas and Cape deep-ocean basins. These and previous sea-floor and land data suggest that basement structures are the result of the breakup of Gondwanaland and the dispersion of the fragments to their present positions. This breakup may have been initiated as early as the Carboniferous Period, but most of the dispersion has taken place since Middle Jurassic. Igneous activity during the early phase may have led to the emplacement of ridges along the continental margin. Later, block faulting and volcanism along the fracture zones that delineate the flow lines of the drifting continents produced Walvis Ridge, Cape Rise, and the Agulhas Plateau. One of these fracture zones, the Agulhas fracture zone, dominates the structural grain of the continental margin and deep-ocean floor off the African southern coast. Sediments as thick as 7 km buried the fragmented continental basement and adjacent oceanic basement off the west coast and formed a broad continental rise and abyssal plain within Cape basin. The source of much of this clastic debris is believed to be the Orange River. In contrast, sedimentation off the southern coast since the breakup of Gondwanaland has been very limited, mostly being restricted to the narrow St. Francis basin atop the shelf. The adjacent continental slope and Agulhas basin have only a thin sediment cover. Much of the sediment that was present on the slope has slumped into the narrow Agulhas fracture zone at the base of the slope. Numerous swells on the southwestern end of the Walvis Ridge, undulating topography of the ocean floor in the western part of the Cape basin, swells on the upper continental rise, and the rough topography of the Agulhas Plateau were formed by the movement of the South Atlantic Bottom Water that enters Cape basin on the west side, flows along the southern flank of Walvis Ridge, and then is deflected southward by the continental slope. Pleistocene eustatic changes in sea level considerably modified the shelf, upper slope, and the eastern end of Walvis Ridge by wave action, turbidity currents, and the Benguela Current.
TL;DR: In this paper, the authors investigated the effect of variable Coriolis parameters on Taylor column formation, taking into account the flow over a bump on a two-layer fluid on a beta plane.
Abstract: An investigation is conducted concerning the lowest-order effect of variable Coriolis parameters on Taylor-column formation, taking into account the flow over a bump on a beta plane. The model considered involves a two-layer fluid on a beta plane. The governing equations for the two layers are discussed along with the characteristics of the general solutions, solutions for two retrograde currents, solutions for two prograde currents, experiments related to the single-layer problem, and the geophysical implications of the results of the investigation.
TL;DR: In this article, a detailed survey of part of the axial trough in the central Red Sea is presented, and the transverse magnetic anomalies, previously recognized by Allan, Phillips and other, have been fully mapped, and a further transverse lineation has been discovered.
Abstract: Summary
New bathymetric, seismic reflexion, gravity and magnetic data have been obtained in a detailed survey of part of the axial trough in the central Red Sea. These data show that the trough is not continuous, but is broken into two sections separated by a shallow region, called the ‘inter-trough zone’. This zone has a thick sediment cover and is devoid of magnetic anomalies. It may represent a fracture zone into which salt and other sediments have flowed, or it may be a section of spreading axis which has remained covered with sediments for an unknown reason.
The transverse magnetic anomalies, previously recognized by Allan, Phillips and other, have been fully mapped, and a further transverse lineation has been discovered. Using three-dimensional computations, a model has been developed which can account for these lineations as the magnetic end effects of a series of short spreading axes offset by closely-spaced transform faults. The development of such a configuration is discussed and can be seen as a natural consequence of the plate geometry in this region.
TL;DR: The rare polycyclic aromatic hydrocarbon minerals curtisite, pendletonite and idrialite have been analyzed by chromatography, and ultraviolet and mass spectrometry as mentioned in this paper.
TL;DR: A purely radiochemical method is described for analysis of 241Pu in environmental samples as mentioned in this paper, showing that fallout-contaminated marine samples, of several kinds and provenances, exhibit241Pu/239,240Pu ratios slightly higher than, but not certainly distinguishable from, those reported for fallout contaminated soils.
TL;DR: The hydrography of surface waters in and near the Amazon River in February and March of 1973 was indicative of "flood" conditions, both in terms of the offshore extension of the freshwater plume and the high concentrations of suspended matter within the river water.
Abstract: The hydrography of surface waters in and near the Amazon River in February and March of 1973 was indicative of "flood" conditions, both in terms of the offshore extension of the freshwater plume and the high concentrations of suspended matter within the river water. While the net transport of Amazon water was NW (due to the Guiana Current), seasonal changes in wind direction resulted in formation of a nearshore counter current along the Para coast. More than 95% of the terrigenous sediment within the Amazon surface waters settles out in the river mouth, before salinity reaches 3. Most of this sediment is resuspended by tides, waves and currents; practically no terrigenous sediment appears to escape offshore. The prime components of suspended matter in the brackish water plume off the Amazon are diatom frustules. Contrary to the suggestions of other workers, Amazon outflow markedly increases the fertility of shelf waters. However, the high production of diatoms is not reflected in the sediments, probably due to rapid recycling as well as to NW transport of frustules by the Guiana Current. Although Amazon-borne silica is initially removed by biologic means, recycling releases it; the ultimate fate of the silica is unknown.
TL;DR: Nitrogen fixation activity appeared to be inversely related to the ability of shipworms to obtain combined-nitrogen compounds in their diet, and could be a significant source of nitrogen for shipwornms and perhaps other oceanic organisms that ingest terrestrial plant material.
Abstract: Nitrogen fixation is associated with four shipworl species A bacterium capable of fixing nitrogen under anaerobic conditions and of liquefying cellulose in culture has been isolated from the gut of one species High fixation rates (up to 15 micrograms of nitrogen per milligram dry weight per hour), which resulted in a doubling of cellular nitrogen in as little as 14 days, was associated with Teredora malleolus from the Sargasso Sea Three species from coastal waters were assayed, and of these juveniles showed the highest fixation rates Nitrogen fixation activity appeared to be inversely related to the ability of shipworms to obtain combined-nitrogen compounds in their diet It could be a significant source of nitrogen for shipwornms and perhaps other oceanic organisms that ingest terrestrial plant material