ALBERT

Description: An estimate of average river particulate matter (RPM) composition was bàsed on analyses of more than 40 elements in the Amazon, Congo, Ganges, Magdalena, Mekong, Parana and Orinoco rivers, to which were added literature data for 13 other major world rivers, covering the whole spectrum of morphoclimatic features. Geographic variations of major elements in RPM are mostly linked to weathering types and to the balance between weathering rate and river transport. As a result of chemical erosion, Al, Fe and Ti are enriched in RPM with respect to the average parent rock, while Na, Ca, Mg and Sr are strongly depleted. These figures are directly related to the relative importance of dissolved and particulate transport in rivers; this has been computed for each of 40 elements. In order to study weathering on a global scale, the total observed elemental fluxes (dissolved + particulate) have been computed and compared to theoretical ones. The latter were derived from the elemental content in the average parent rock and the total quantity of weathered material, computed from the Al ratio in RPM and in parent rock. Observed and theoretical fluxes are balanced for the less mobilized elements (rare earths, Co, Cr, Cs, Fe, Mn, Rb, Si, Th, Ti, U and V) for which no enrichment relative to Al is noted in RPM, and for B, Ba, Ca, K, Mg, Na, Sr which are relatively depleted in RPM due to their high dissolved transport. Additional fluxes have been found for Br, Sb, Pb, Cu, Mo, Zn and are possible also for Ni and P. This is reflected by marked enrichments in RPM relative to Al for the poorly or moderately dissolved transports (Pb, Cu, Zn). Several hypotheses involving either the natural origin (volcanic dust, marine aerosols, geochemical fractionation) or the artificial origin (worldwide pollution) are discussed to explain these discrepancies, assuming river transport and weathering either to be in a steady state on a global scale or not. However, none of them can fully account for these additional fluxes. It is most likely that these excesses have multiple origins, anthropogenic or natural or both. The comparison between RPM and deep-sea clay compositions emphasizes the prime influence of river input on oceanic sedimentation of Si, Al, Fe, Ti, lanthanides, Sc, Rb, V, etc. A few elements such as Zn, Sb, occur in excess in RPM as compared to deep-sea clays; in order to balance this excess, a remobilization of these elements out of the sediment can be considered. Finally, the enrichment of Co, Cu, Mn and Ni in deep-sea clays compared to RPM is discussed and attributed to several sources and processes.

Description: The coagulation of hydrosols was investigated theoretically and experimentally. A reduced form of the particle size distribution function, designated “self-preserving,” was found to satisfy Smoluchowski's equations of coagulation by Brownian motion and shear flow. Brownian motion coagulation experiments with two heterogeneous hydrosols showed that the distributions were self-preserving. The rate of coagulation for heterogeneous systems was found to be second order in total particle concentration, consistent with the self-preserving form of the distribution function. Coagulation experiments were carried out in a simple laminar shear field using a homogeneous Dow polystyrene latex dispersion. Smoluchowski's shear flow theory was confirmed for shear rates ranging from 1 to 80 sec.−1 The shear coagulation of a heterogeneous emulsion was studied at several shear rates, and the size distributions were self-preserving.

Description: Fecal excretion of calcium of endogenous origin has been measured in 52 studies in 33 adult human subjects, under full metabolic balance conditions. Endogenous fecal calcium averaged .130 ± .047 Gm. per day, was positively correlated with both fecal calcium and dietary calcium and was inversely correlated with fractional calcium absorption. The regression line relating endogenous fecal calcium with fractional absorption allowed estimates for total intestinal calcium secretion at both zero and 100 per cent absorption; from these estimates it was calculated that approximately 15 per cent of the total intestinal calcium secretion was nonabsorbable even under conditions when dietary calcium was completely absorbed (presumably because it enters the gut caudad of the absorption sites). Total intestinal calcium secretion, calculated so as to allow for this nonabsorbable fraction, averaged .194 ± .073 Gm. per day, and could not be correlated with age, sex, dietary calcium intake, caloric intake, urine calcium, or plasma calcium. A weak correlation with body size (weight, surface area) was observed. The conditions studied were principally disorders of bone, calcium, and parathyroid metabolism, and in most of them total intestinal calcium secretion appeared identical. The sole exception was seen in two studies on a patient with acromegaly, in which total intestinal calcium secretion was over twice the mean value for the remainder of the group.

Description: This chapter discusses the Maillard reaction. Results of the many investigations into the mechanism of the Maillard reaction support one of two main theories. The first assumes the formation of glycosylamines that undergo the Amadori (or, for ketoses, the Heyns) rearrangement. The 1-amino-l-deoxyketose derivative (or 2-amino-2-de- oxyaldose derivative) formed may be dehydrated and cyclized to form furan derivatives, or it may enolize. In either case, intermediates that are readily transformed into brown compounds are formed. A third possibility is for the deoxy sugar derivative to react with more amino acid to form colored products. The many workers who have supported this mechanism found also that optimum conditions for occurrence of the Maillard reaction are (1) fairly low water content, (2) a pH of 7 to 10, and (3) a high temperature. Nevertheless, some reaction occurs under conditions far removed from these, but in the absence of moisture there is no reaction. The formation of an acyclic Schiff base as an initial step is not very likely, since replacement of the aldose by salicylaldehyde caused only a very small loss of amino groups. The second theory of the mechanism of the browning reaction is of recent origin and maintains that the browning reaction and the Maillard reaction are separate and distinct. Browning, according to this school of thought, is due to the effect of pH on the sugar and can occur over a wide range of pH, whereas the Maillard reaction proceeds only in alkaline media.

Description: Several types of abyssal bedforms have been discovered during surveys with a deeply towed instrument package at water depths of 1.5–6 km in the Pacific and Atlantic Oceans. Cores and current-meter records obtained at the same sites provide data for interpreting their dynamics. Wave and current ripples are best portrayed in bottom photographs, but medium-scale bedforms, including sand waves, mud waves and erosional furrows, are described by interpreting high-resolution side-looking sonar records. The largest examples affect surface-ship echograms, though their shape and structure can seldom be resolved without near-bottom observations. Wave ripples are common on the slopes of seamounts and ridges, while current ripples and sand waves occur beneath some fast thermohaline currents whose beds are shallower than the foraminiferal compensation depth. Depositional and erosional bedforms in cohesive sediment have been found beneath the deepest thermohaline currents; they may be restricted to areas where the flow is unusually steady in direction.

Description: Fourteen instances of whales entangled in submarine cables are reported. Ten entanglements occured off the Pacific coast of Central and South America. Six cases occured in about 500 fathoms, with 620 fathoms the maximum depth reported. Five entanglements occured in the period, Februray-March-April. All whales positively identified were sperm whales. The submarine cable was generally wrapped around jaw and often around the flukes and fins. The cable was rarely broken but always badly mauled. The entanglements often occured near former repairs where there is a chance for extra slack cable on the bottom. Two photographs of a sperm whale entangled in a cable and one photograph of a whale-jaw entangled in a cable are presented. It is concluded that sperm whales often swim alog the sea floor in depths as grat as 620 fathoms. It is suggested that the whales become entangled while swimming along with their jaw plowing through the sediment in search of food. It is possible that the whales attack tangled masses of slack cable mistaking them for items of food.

Description: This chapter throws the attention on the methods of sampling the benthos, which has been directed mainly to the operation of the gear at sea and to such other factors as may influence sampling methods. This chapter briefly traces the history of benthos investigations, and then considers how far the instruments now available provide with the quantitative samples. It also shows how advances in other fields, such as radio-position finding, sonar and electronic equipment have increased the precision of our sampling methods. Moreover, sorting and sieving on board ship can be considered and brief mention made of methods of soil analysis and biomass determination. This chapter discusses the two possible approaches for the development of satisfactory quantitative collecting methods. First the improvement of the grab-type of instrument, with particular reference to increasing penetration and the perfection of release gear for the open sea, and second; the development of a wide-core sampler, like the Knudsen sampler, which works satisfactorily in the open sea. Moreover, statistics need to be even more fully applied, where collecting methods justify them, to such problems as the degree and scale of dispersion of individuals.

Description: A complete set of linearly independent relationships among the different cross spectral components obtained from pairs of moored instruments is derived which can be utilized to test whether or not the observed fluctuations within the internal wave frequency band represent a field of propagating internal waves. A further complete set of relationships is derived which enables to test whether or not the internal wave field is horizontally isotropic and (or) vertically symmetric. These relations are compared with corresponding relations for alternative models (standing internal wave modes, three-dimensional isotropic turbulence) and their capability to discriminate between the various models is investigated. The tests are applied to a set of data for which it is found that the observed fluctuations are consistent with both propagating and standing internal waves whereas isotropic turbulence must be rejected for the most part of the internal wave frequency band.

Description: This chapter discusses the carbon turnover, calcification, and growth in coral reefs. Carbon turnover within a total reef community is a function of two distinct, biochemically interacting cycles. The first is the metabolic cycle consisting of the photosynthetic fixation of CO2 and the release of CO2 by respiration and decomposition processes. Superimposed on this are the direct incorporation of organic compounds (dissolved or particulate; living or non-living) originating outside the reef systems (in the adjacent ocean waters), and the loss of organic compounds from the reef system into the out-flowing water. The second is the inorganic carbonate cycle involving the biological and non-biological precipitation and dissolution of carbonates. Superimposed on this is the loss of particulate carbonates in suspension in the out-flowing water. The main chemical component of a coral-reef system is calcium carbonate, which occurs either as high-Mg calcite, aragonite, or low-Mg calcite. The mean calcification values in various environments at One Tree Reef are presented in the chapter. These data may be converted to an implied vertical growth rate potential assuming that accrual is dominantly aragonite (density = 2.89 g cm–3) and that there is 50% porosity after normal compaction.