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Growth efficiency in Artemia under laboratory conditions
964
Oceanographic Abstracts
but supplemented with other material. Exceptionally large size, an elongate telson ar.d peculiar hooks on the dactyls of the ambulatory I*.gs distinguish this form from described glaucothoes of other genera. Lack of detailed information on other species within the genus hampers comparison and evaluation of characters. PURDY, E. G., 1963. Recent calcium carbonate facies of the Great Bahama Bank. 2. Sedimentary facies. J. Geol., 71 (4): 472~197. Statistical analysis of the constituent composition and grain-size data accumulated for 218 Bahan'.ian sediment samples resulted in the delineation+of the following five facies: (I) coralgal facies-characterized by a relative abundance o f skeletal grains, particularly coral and calcareous algae fragments; (2) oolitic facies--characterized by an abundance of o61itically coatcd grains: (3) grap=stone facies--typified by an abundance of grap=stone and cryptocrystalline grains: (4) pelletmud facies--characterized by an abundance of fecal pellets and particles smaller than ~ ram: and (5) mud facies--typified by an abundance of particles smaller than i mm and a relative paucity of indurated fecal pellets. The coralgal facies owes its distinctiveness to a relative lack of non-skeletal calcium carbonate precipitation and to the large areas of rock bottom that characterize this depositionzl environment. In contrast, differences among three o f the other four facies are considered to be primarily the product o f differential current strength, with current velocities progressively decreasing in intensity from the oolitic to the pellet-mud facies. The contrast between pellet-mud and mud deposits appears to be duelargely toadecreased rate of formation and/orinduration of fecal pellets in t he mudenviron ment. Ideally one might expect Bahamian facies to be distributed in a series of five concentric bands parallel to the bank's margin. The karst surface of the submerged Pl=istocene basement rock, however, creates local current conditions that cause the development of a somewhat patchlike facies pattern. RAP, V. N., 1963. An instrument for measuring small changes in the velocity of sound in the sea. Ind. J. Pure Appl. Phys., 1 (2): 69-72. The design and construction of a sound velocity meter for measuring small changes in the velocity of propagation o f sound in the sea are described. The instrument is based on the principle of measuring the advance o f phase as a 500 kc/s sound wave travels a fixed distance in the medium. The errors introduced due to the standing waves and the leakage of the transmitted signal are analysed. The instrument has been found to be accurate enough to determine with certainty a change in velocity of 0'35 ft/sec and is suitable for studying the detailed velocity variation due to thermal microstructure in the upper layers of sea surface. RAP, T. S. SATYANARAYANA,1963. On the pattern of surface circulation in the Indian Ocean as deducted from drift bottle recoveries. Ind. J. Met. Geophys., 14 (I): 64-67. In the South Indian Ocean the traj.~ctories of drift bottles indicate the occurrence of two well-defined surface currents; one is the West Wind Drift from Africa towards Australia. The other is the South Equatorial Current. There is no evidence ,from the available drift bottle data for the occurrence of a west Australian current flowing north, nor is there evidence for the occurrence of the Equatorial counter-current. In the Indian Ocean, north o f the equator, the drift of each bottle depends on the period when it was released and recovered. During the northeast monsoon (December-April) the bottles drifted westward; during the southwest monsoon the bottles moved eastward movement. This agrees with the available data. RAYMONT, J. E. G. and J. SHIELDS, 1963. Toxicity of copper and chromium in the marine environment. Int. J. Air Wat. Poll., 7 (4/5): 435-443. These investigations suggest that with Nereis a toxic threshold exists for copper at a level of about 0"l ppm Cu, but that chromium is less poisonous, the threshold approaching ten times this value. The few experiments conducted with the crab Carcinus, indicate that copper is at least ten times, and possibly nearer twenty times, more toxic than chromium; with Leander copper appears to be also more poisonous. Carcinus is much more resistant than Nereis to both copper and chromium poisoning. With copper the difference in threshold value is approximately ten times, but in the case of chromium, Carcinus appears to be much more resistant. These differences may presumably be attributed to specific differences in the physiology of the animals concerned, such as permeability of the gut and body wall, the composition of the body tissues and rates o f excretion. To some extent the differences may he also correlated with the size o f the experimental animal. I~EVE, M. R., 1963. Growth efficiency in Artemia under laboratory conditions. Biol. Bull., 125 (1): 133-145. The efficiency of growth of four laboratory populations of Artemia in different food concentrations was studied over a period from birth to ca. double the time required to reach sexual maturity. Uptake o f food and increase in length, and hence weight, were measured daily. Efficiency rose at
Oceanographic Abstracts
965
first, up to the time at which the animals were growing at their maximum rate, when the highest peak cumulative effici~nci~s (79 per cent) were obtained in the lowest food concentrations. These values then fell as the animals approached their maximum size. in other experiments on young animals in their first few days of growth, it was found that efficiency increased with temperature between 5 ° and 30~C., that there was an optimum salinity of about 350o0, at which, efficiency was greatest, and an optimum food concentration of 25-30 cells/mm 3. RHD, J. L., JR., 1963.
Measurements of the California Countercurrent off Baja California.
J. Geophys. Res., 68 0 6 ) : 4819-4822. Thirteen parachute drogues were laid at a depth of 250 m along a I l0 km line extending southwestward from the 1000 m isobath off northern Baj~t California. A movement to the northwest was observed on the inshore 28 km of the line, with a maximum speed of about,8 cm/sec at the centre. A movement to the southeast was observed along the next 70 km, with a maximum speed of about 13 cm/sec. At the outer end of the line, the movement was very slow, ,probably within the measurement error, and the geostrophic flow (which agreed with the results of the drogue thovements in the inshore area) indicated northwesterly flow. These results are very similar in pattern to those obtained earlier in an area 700 k m f a r t h e r north'; but the velocities and the widths of the various flows are much less. REITZEL, J., 1963. A region of uniform heat flow in the North Atlantic. d. Geophys. Res., 68 (18): 5191-5196. Heat flow was determined, at sixteen stations regularly spaced over a region of the North American basin b.~tween Bermuda and the Bahama Banks. The results show a remarkable uniformity of heat flow in this area, which measures about 800 by 900 kin. The mean heat flow at the sixteen stations is 1.14 vcal/cm z sac, with a standard deviation of 0-06. When allowance is made for experimental errors the actual standard deviation of heat flow in the region is estimated to be only 41%. Another measurement made at the,sotRhern edge of this area, near the Puerto Rico trench, showed a heat flow of 1-76 p.cal/crn2 sec, while three measurements made a few hundred-km to the northwest, close to the continental slope, gave values of 1.17, 0-94, and 0-81 veal/era z sac. RICHAROS, A. F., 1961. Investigations of deep-sea sediment cores. 1. Shear strength, bearing capacity and consolidation. U. S. Navy Hydrogr. Off., Tech. Rept., T R - 6 3 : 7 0 pp. Thirty gravity and piston cores were collected from eight areas in the North Atlantic, West Mediterranean, and Cer, tral Pacific. They were transported to the laboratory in Washington, D.C., with protection against mechanical vibration and, so far as possible, in an upright position. Sediments were composed of clayey silt- and silty clay-sized particles, predominantly of terriginous origin. A knowledge of the gross core recovery ratio (gross core length/corer penetration distance) is of importance for engineering and other investigations requiring sample depth. Evidence is presented from recent Swedish investigations that this ratio may not be always 100 per cent for piston cores, as is commonly assumed. The ratio is variable for gravity-type cores; it appears to be a function of the design. Well,engineered gravity corers have gross recovery ratios about 100 per cent in the upper 40 to 75 cm' and smaller ratios below this depth, Poorly-engineered (for undisturbed sampling) gravity corers may have core shortening proportional to the. distance penetrated and gross recovery ra
U. S. Navy Hydrogr. Off:, Tech.' Rapt., TR-106:146 pp. Measurements of mass physical proper~;ies ¢¢ere made in the laboratory on thirty-five gravity- a n d piston-type sediment cores, ranging in length from 30-511 cm, collected from ocean depths of 400--5120 m. Sample composition was predominantly silty clay- and clayey silt-s~¢ material, chiefly of terrigenous origin.
Oceanographic Abstracts
but supplemented with other material. Exceptionally large size, an elongate telson ar.d peculiar hooks on the dactyls of the ambulatory I*.gs distinguish this form from described glaucothoes of other genera. Lack of detailed information on other species within the genus hampers comparison and evaluation of characters. PURDY, E. G., 1963. Recent calcium carbonate facies of the Great Bahama Bank. 2. Sedimentary facies. J. Geol., 71 (4): 472~197. Statistical analysis of the constituent composition and grain-size data accumulated for 218 Bahan'.ian sediment samples resulted in the delineation+of the following five facies: (I) coralgal facies-characterized by a relative abundance o f skeletal grains, particularly coral and calcareous algae fragments; (2) oolitic facies--characterized by an abundance of o61itically coatcd grains: (3) grap=stone facies--typified by an abundance of grap=stone and cryptocrystalline grains: (4) pelletmud facies--characterized by an abundance of fecal pellets and particles smaller than ~ ram: and (5) mud facies--typified by an abundance of particles smaller than i mm and a relative paucity of indurated fecal pellets. The coralgal facies owes its distinctiveness to a relative lack of non-skeletal calcium carbonate precipitation and to the large areas of rock bottom that characterize this depositionzl environment. In contrast, differences among three o f the other four facies are considered to be primarily the product o f differential current strength, with current velocities progressively decreasing in intensity from the oolitic to the pellet-mud facies. The contrast between pellet-mud and mud deposits appears to be duelargely toadecreased rate of formation and/orinduration of fecal pellets in t he mudenviron ment. Ideally one might expect Bahamian facies to be distributed in a series of five concentric bands parallel to the bank's margin. The karst surface of the submerged Pl=istocene basement rock, however, creates local current conditions that cause the development of a somewhat patchlike facies pattern. RAP, V. N., 1963. An instrument for measuring small changes in the velocity of sound in the sea. Ind. J. Pure Appl. Phys., 1 (2): 69-72. The design and construction of a sound velocity meter for measuring small changes in the velocity of propagation o f sound in the sea are described. The instrument is based on the principle of measuring the advance o f phase as a 500 kc/s sound wave travels a fixed distance in the medium. The errors introduced due to the standing waves and the leakage of the transmitted signal are analysed. The instrument has been found to be accurate enough to determine with certainty a change in velocity of 0'35 ft/sec and is suitable for studying the detailed velocity variation due to thermal microstructure in the upper layers of sea surface. RAP, T. S. SATYANARAYANA,1963. On the pattern of surface circulation in the Indian Ocean as deducted from drift bottle recoveries. Ind. J. Met. Geophys., 14 (I): 64-67. In the South Indian Ocean the traj.~ctories of drift bottles indicate the occurrence of two well-defined surface currents; one is the West Wind Drift from Africa towards Australia. The other is the South Equatorial Current. There is no evidence ,from the available drift bottle data for the occurrence of a west Australian current flowing north, nor is there evidence for the occurrence of the Equatorial counter-current. In the Indian Ocean, north o f the equator, the drift of each bottle depends on the period when it was released and recovered. During the northeast monsoon (December-April) the bottles drifted westward; during the southwest monsoon the bottles moved eastward movement. This agrees with the available data. RAYMONT, J. E. G. and J. SHIELDS, 1963. Toxicity of copper and chromium in the marine environment. Int. J. Air Wat. Poll., 7 (4/5): 435-443. These investigations suggest that with Nereis a toxic threshold exists for copper at a level of about 0"l ppm Cu, but that chromium is less poisonous, the threshold approaching ten times this value. The few experiments conducted with the crab Carcinus, indicate that copper is at least ten times, and possibly nearer twenty times, more toxic than chromium; with Leander copper appears to be also more poisonous. Carcinus is much more resistant than Nereis to both copper and chromium poisoning. With copper the difference in threshold value is approximately ten times, but in the case of chromium, Carcinus appears to be much more resistant. These differences may presumably be attributed to specific differences in the physiology of the animals concerned, such as permeability of the gut and body wall, the composition of the body tissues and rates o f excretion. To some extent the differences may he also correlated with the size o f the experimental animal. I~EVE, M. R., 1963. Growth efficiency in Artemia under laboratory conditions. Biol. Bull., 125 (1): 133-145. The efficiency of growth of four laboratory populations of Artemia in different food concentrations was studied over a period from birth to ca. double the time required to reach sexual maturity. Uptake o f food and increase in length, and hence weight, were measured daily. Efficiency rose at
Oceanographic Abstracts
965
first, up to the time at which the animals were growing at their maximum rate, when the highest peak cumulative effici~nci~s (79 per cent) were obtained in the lowest food concentrations. These values then fell as the animals approached their maximum size. in other experiments on young animals in their first few days of growth, it was found that efficiency increased with temperature between 5 ° and 30~C., that there was an optimum salinity of about 350o0, at which, efficiency was greatest, and an optimum food concentration of 25-30 cells/mm 3. RHD, J. L., JR., 1963.
Measurements of the California Countercurrent off Baja California.
J. Geophys. Res., 68 0 6 ) : 4819-4822. Thirteen parachute drogues were laid at a depth of 250 m along a I l0 km line extending southwestward from the 1000 m isobath off northern Baj~t California. A movement to the northwest was observed on the inshore 28 km of the line, with a maximum speed of about,8 cm/sec at the centre. A movement to the southeast was observed along the next 70 km, with a maximum speed of about 13 cm/sec. At the outer end of the line, the movement was very slow, ,probably within the measurement error, and the geostrophic flow (which agreed with the results of the drogue thovements in the inshore area) indicated northwesterly flow. These results are very similar in pattern to those obtained earlier in an area 700 k m f a r t h e r north'; but the velocities and the widths of the various flows are much less. REITZEL, J., 1963. A region of uniform heat flow in the North Atlantic. d. Geophys. Res., 68 (18): 5191-5196. Heat flow was determined, at sixteen stations regularly spaced over a region of the North American basin b.~tween Bermuda and the Bahama Banks. The results show a remarkable uniformity of heat flow in this area, which measures about 800 by 900 kin. The mean heat flow at the sixteen stations is 1.14 vcal/cm z sac, with a standard deviation of 0-06. When allowance is made for experimental errors the actual standard deviation of heat flow in the region is estimated to be only 41%. Another measurement made at the,sotRhern edge of this area, near the Puerto Rico trench, showed a heat flow of 1-76 p.cal/crn2 sec, while three measurements made a few hundred-km to the northwest, close to the continental slope, gave values of 1.17, 0-94, and 0-81 veal/era z sac. RICHAROS, A. F., 1961. Investigations of deep-sea sediment cores. 1. Shear strength, bearing capacity and consolidation. U. S. Navy Hydrogr. Off., Tech. Rept., T R - 6 3 : 7 0 pp. Thirty gravity and piston cores were collected from eight areas in the North Atlantic, West Mediterranean, and Cer, tral Pacific. They were transported to the laboratory in Washington, D.C., with protection against mechanical vibration and, so far as possible, in an upright position. Sediments were composed of clayey silt- and silty clay-sized particles, predominantly of terriginous origin. A knowledge of the gross core recovery ratio (gross core length/corer penetration distance) is of importance for engineering and other investigations requiring sample depth. Evidence is presented from recent Swedish investigations that this ratio may not be always 100 per cent for piston cores, as is commonly assumed. The ratio is variable for gravity-type cores; it appears to be a function of the design. Well,engineered gravity corers have gross recovery ratios about 100 per cent in the upper 40 to 75 cm' and smaller ratios below this depth, Poorly-engineered (for undisturbed sampling) gravity corers may have core shortening proportional to the. distance penetrated and gross recovery ra
U. S. Navy Hydrogr. Off:, Tech.' Rapt., TR-106:146 pp. Measurements of mass physical proper~;ies ¢¢ere made in the laboratory on thirty-five gravity- a n d piston-type sediment cores, ranging in length from 30-511 cm, collected from ocean depths of 400--5120 m. Sample composition was predominantly silty clay- and clayey silt-s~¢ material, chiefly of terrigenous origin.