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On changes in some biological parameters in the North Sea sole (Solea solea L.)
Oceanographic Abstracts
191
February and attained maximum values during April and May, the average concentrations of dissolved amino acids (total) varied between 900 and 1200 nmole 1.-1 but larger variations were encountered at the surface and in the vicinity of the sediment. The influence of meteorological conditions and the effect of the sediment on the distribution of nitrogenous substances were taken into account. Combined dissolved amino acids were more abundant than free dissolved amino acids in 90% of the cases. The concentrations of dissolved amino acids observed in a zone bordering the North Mediterranean are comparable to those found in other regions of the world. DENNIS J. G., 1976. Geosynklinale, Orogenese und Plattentektonik. Z. dt. geoL Ges., 127 (1): 73-85. The development of geosynclines and orogenic belts, as deduced from geological observations, is compared and contrasted with the geodynamic model of active back-arc basins and of asthenospbere processes under them. Orogeny in the "classical" sense accompanies continental collision. Here, the geological and the geodynamic models are in good agreement. The geodynamic hypotheses involved are back-arc spreading (Karig), and a numerical model of back-arc asthenosphere flow (Andrews & Sleep). The current analog of Stille's orthogeosynclinal zone is the active marginal basin. However, Stille's geotectonic cycle cannot be applied in the case of trench deposits, nor in chains of the Andean type. DE VEEN J. F., 1976. On changes in some biological parameters in the North Sea sole (Solea solea L.) J. Cons. int. Explor.
Mer, 37 (I): 60-90. Biological parameters such as length and weight-at-age, fecundity and length at first maturation, derived from market sampling in Dutch ports, showed significant changes in the period under observation (1957 - 1973). An attempt was made to correlate these changes with environmental factors such as tile density of the sole stock, temperature in the growth-season, eutrophication, and fishing effort. Of these factors significant correlations were only found with fishing effort and with indices of the disturbance of bottom layers by active gears. Additional evidence points to the possibility that the amount of beam-trawling with chains has a positive effect on the growth rate and on other biological parameters of the sole. DICKSON R. R., I976. Field tests of seabed drifters, using sector-scanning sonar techniques. Z Cons. int Explor. Met, 37 (1): 3-15. Woodhead seabed drifters equipped with acoustic transpounding tags were tracked by sector scanning sonar in four separate exercises off the Suffolk coast (Southern North Sea). Remote measurements of the height of each drifter relative to the sea bed were made at 5 min intervals over at least one tide, and these observations were related to measurements of midwater current velocity obtained at sites close to the drifters' paths. These results show that the drifters remain on the sea bed until the midwater current exceeds 50 cm s -1 (approximately). Thereafter, at midwater current velocities of 50 - 95 cm s -1 saltation occurs at an increasing frequency though the drifter tends to remain within 3.5 m of the sea bed. At midwater current velocities greater than 95 cm s -~ the drifter lifts from the near-bottom layer'to glide for extended periods of time in midwater. DROBISHEVA S. S. and Yu. P. ASEEV, 1976. On the life cycle ofPenaeus semisulcatus (Crustacea, Decapoda, Penaeidae) in the Persian Gulf. (In Russian; English abstract.) Zool. Zh., 55 (5): 769-771. The shrimp P semisulcatus of the Persian Gulf lives for one year and their population is, therefore, represented by specimens of only one generation. Spawning takes place in November - March. The size of sexually mature shrimps is 160 - 180 mm. The duration of spawning determines the heterogenous size composition of the young, and the long period of maturation of the whole population. Since the reproduction is ensured by specimens of only one generation, the total population density of shrimps is subjected to marked annual fluctuations. DUDLEY W. C., 1976. Cementation and iron concentration in foraminifera on manganese nodules. J. foram. Res., 6 (3): 203-207. Energy dispersive X-ray analysis in conjunction with scanning electron microscopy has revealed high concentrations of iron in the tests of the benthic agglutinated foraminifera Saccorhiza ramosa and Tolypammina vagans found on the surface of deep-sea ferromanganese nodules. Although highest iron values were found on the smooth, cement-rich interior surface of the foraminiferal tube, chemical removal of the iron without a collapse of the framework of the test suggests that iron is present as a surficial deposit rather than as a component of the cement. Areas of the nodule underlying and adjacent to the foraminiferal tubes were not depleted in iron relative to the surface of the nodule as a whole. EBERHARDT L . L . , R. O. GILBERT, H. L. HOLLISTER and J. M. THOMAS, 1976. Sampling for contaminants in ecologicaJ systems. Environ. ScL Technol., 10 (9): 917-925. A framework for designing schemes to sample for contaminants requires a clear statement of objectives, selection of an appropriate model and error system, and should yield cost-effective ways to sample to meet specific objectives. After reviewing five classes of models that might be used in studies of contaminants, we conclude that a universal model is presently out of reach, but that
191
February and attained maximum values during April and May, the average concentrations of dissolved amino acids (total) varied between 900 and 1200 nmole 1.-1 but larger variations were encountered at the surface and in the vicinity of the sediment. The influence of meteorological conditions and the effect of the sediment on the distribution of nitrogenous substances were taken into account. Combined dissolved amino acids were more abundant than free dissolved amino acids in 90% of the cases. The concentrations of dissolved amino acids observed in a zone bordering the North Mediterranean are comparable to those found in other regions of the world. DENNIS J. G., 1976. Geosynklinale, Orogenese und Plattentektonik. Z. dt. geoL Ges., 127 (1): 73-85. The development of geosynclines and orogenic belts, as deduced from geological observations, is compared and contrasted with the geodynamic model of active back-arc basins and of asthenospbere processes under them. Orogeny in the "classical" sense accompanies continental collision. Here, the geological and the geodynamic models are in good agreement. The geodynamic hypotheses involved are back-arc spreading (Karig), and a numerical model of back-arc asthenosphere flow (Andrews & Sleep). The current analog of Stille's orthogeosynclinal zone is the active marginal basin. However, Stille's geotectonic cycle cannot be applied in the case of trench deposits, nor in chains of the Andean type. DE VEEN J. F., 1976. On changes in some biological parameters in the North Sea sole (Solea solea L.) J. Cons. int. Explor.
Mer, 37 (I): 60-90. Biological parameters such as length and weight-at-age, fecundity and length at first maturation, derived from market sampling in Dutch ports, showed significant changes in the period under observation (1957 - 1973). An attempt was made to correlate these changes with environmental factors such as tile density of the sole stock, temperature in the growth-season, eutrophication, and fishing effort. Of these factors significant correlations were only found with fishing effort and with indices of the disturbance of bottom layers by active gears. Additional evidence points to the possibility that the amount of beam-trawling with chains has a positive effect on the growth rate and on other biological parameters of the sole. DICKSON R. R., I976. Field tests of seabed drifters, using sector-scanning sonar techniques. Z Cons. int Explor. Met, 37 (1): 3-15. Woodhead seabed drifters equipped with acoustic transpounding tags were tracked by sector scanning sonar in four separate exercises off the Suffolk coast (Southern North Sea). Remote measurements of the height of each drifter relative to the sea bed were made at 5 min intervals over at least one tide, and these observations were related to measurements of midwater current velocity obtained at sites close to the drifters' paths. These results show that the drifters remain on the sea bed until the midwater current exceeds 50 cm s -1 (approximately). Thereafter, at midwater current velocities of 50 - 95 cm s -1 saltation occurs at an increasing frequency though the drifter tends to remain within 3.5 m of the sea bed. At midwater current velocities greater than 95 cm s -~ the drifter lifts from the near-bottom layer'to glide for extended periods of time in midwater. DROBISHEVA S. S. and Yu. P. ASEEV, 1976. On the life cycle ofPenaeus semisulcatus (Crustacea, Decapoda, Penaeidae) in the Persian Gulf. (In Russian; English abstract.) Zool. Zh., 55 (5): 769-771. The shrimp P semisulcatus of the Persian Gulf lives for one year and their population is, therefore, represented by specimens of only one generation. Spawning takes place in November - March. The size of sexually mature shrimps is 160 - 180 mm. The duration of spawning determines the heterogenous size composition of the young, and the long period of maturation of the whole population. Since the reproduction is ensured by specimens of only one generation, the total population density of shrimps is subjected to marked annual fluctuations. DUDLEY W. C., 1976. Cementation and iron concentration in foraminifera on manganese nodules. J. foram. Res., 6 (3): 203-207. Energy dispersive X-ray analysis in conjunction with scanning electron microscopy has revealed high concentrations of iron in the tests of the benthic agglutinated foraminifera Saccorhiza ramosa and Tolypammina vagans found on the surface of deep-sea ferromanganese nodules. Although highest iron values were found on the smooth, cement-rich interior surface of the foraminiferal tube, chemical removal of the iron without a collapse of the framework of the test suggests that iron is present as a surficial deposit rather than as a component of the cement. Areas of the nodule underlying and adjacent to the foraminiferal tubes were not depleted in iron relative to the surface of the nodule as a whole. EBERHARDT L . L . , R. O. GILBERT, H. L. HOLLISTER and J. M. THOMAS, 1976. Sampling for contaminants in ecologicaJ systems. Environ. ScL Technol., 10 (9): 917-925. A framework for designing schemes to sample for contaminants requires a clear statement of objectives, selection of an appropriate model and error system, and should yield cost-effective ways to sample to meet specific objectives. After reviewing five classes of models that might be used in studies of contaminants, we conclude that a universal model is presently out of reach, but that