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Oxygen consumption in a brackish water crustacean, Sesarma plicatum (Latreille) and a marine crustaccean
Oceanographic Abstracts
345
MADANMOHANRAO, G., and K. PAMPAPATH1 RAO, 1962. Oxygen consumption in a brackish water crustacean, Sesarma plicatum (Latreille) and a marine crustacean, Lepas anserifera L. Crustaceana, 4 (l): 75-81. Der Sauerstoffverbrauch des Brackwasserkrebses Sesarma plicatum wurde ermittelt in Leitungswasser, sowie in 25%, 50%, 75% und 100% Meerwasser (Mw). Der Sauerstoffverbrauch war am geringsten in 50% Mw (dem nattirlichen Medium des Versuchstieres) und stieg an in Salzgehalten tiber oder unter 50% mit Maximalwerten im Leitungswasser. Kleinere Individuen zeigten einen st~irkeren Anstieg im Sauerstoffverbrauch nach Ver/inderung des Salzgehaltes als gr/Sssere. Lepas anserifera, ein mariner Cirripedier, wurde in ahnlicher Weise untersucht, und zwar in 25%, 50%, 75%, 100%, 125% und 150% Mw. In 25°0 und in 150% wurden abnormal niedrige Respirationswerte erhalten und die Versuchstiere starben schliesslich. Innerhalb der anderen Salzgehaltsstufen (50 bis 125% Mw) war der Sauerstoffverbrauch am niedrigsten in 100°o Mw (dem natiirlichen Medium des Cirripediers). Der Verbrauch erh6hte oder erniedrigte sich mit steigendem (125% M w ) o d e r fallendem (75%; 50% Mw)Salzgehalt. Diese Ver/inderungen der Stoffwechselintensit/it in verschiedenen Salzgehalten werden gedeutet als Stoffwechselkompensationen : die Versuchstiere zeigen den geringsten Sauerstoffverbrauch in iherem nattirlichen Medium. MAHADEVA, N., 1962. Preliminary report on the experiments with Marutoku-B net and a 45 cm x 90 cm net of No. 0 bolting silk off Trincomalee, Ceylon, during October 1960. lndo-Paci/w/-Tsh. Council, FAO, Proc., 9th Sess., (2/3): 17-24. Comparative studies with the Marutoku-B net and another 45 cm. net of different construction revealed that the Japanese net collected more plankton per cubic meter of water filtered, although filtering a smaller volume o f water. Descriptions of the two nets, and of the methods employed in operating the nets, removing and treating the plankton and of the problems encountered are given. MAKSIMOV, I. V., and V. N. VOROB'YEV,1961. The study of deep currents in the Antarctic Ocean. Abstract : Sov.-Bloc Res. Geophy. Astron. Space, 1962 (42): 7. JPRS 15,068 OTS 61-11147-42. A method for studying deep currents is described and applied to data previously collected in the Antarctic Ocean. This modified ' differential' method is as follows : the electromagnetic method is used to measure currents at the surface and the dynamic method is used to compute movements of deep water relative to the surface. The deep current is determined as the vector difference between the surface current and the current computed for a depth relative to the surface. This work is done in a 'dynamic square' formed by a closed line made up of four cross sections, along which currents are continuously recorded by the electromagnetic method. The sides of the ' square ' should be 30 miles in length. An example of the application of the method is given. The location of the stations used is shown in Figure 2. Curves o f the vertical distribution of current velocity (0-3000 m) are shown in Figure 3 ; Table 1 gives data on deep currents in this area (0-2000 and 3000 m).
Byull. Soy. Antark. Eks., 31: 35-39.
MANGELSDORF, P. C., JR., 1962. The world's longest salt bridge. Mar. Sci. lnstrum., Instrum.
Soc., Amer., Plenum Press, N.Y., 1 : 173-185. A variation of the Geomagnetic Electrokinetograph has been developed in which the electrodes remain aboard ship immersed in sea water at constant composition and temperature. The electrical connection to the sea is made with lengths of polyethylene tubing filled with sea water. This arrangement greatly reduces the sensitivity of the system to gradients of salinity and temperature in the sea. It also permits a direct electrode zero by means of a sea water shunt between the two electrodes. MARGALEF, R., 1962. Fluctiones en abundancia y asequibilidad causadas por factores bioticos.
Methodological Paper, No. 1 : 1265-1285. In the study of fluctuations due to biotic factors it may be useful to replace the usual way of assessing separately the effects o f different factors on the populations by a more synthetic approach, starting from the consideration of the whole ecosystem whose different structural elements (niches) are linked by feedback relations. A number of properties common to such systems can be applied automatically in any special case. Fluctuations may be internal to the ecosystem and then related only to availability, or they may mean a change in the composition of populations, as free oscillations (predator,' prey oscillations) or as forced fluctuations imposed directly or indirectly by environmental (rhythmic) changes. Sardines and related species belong to a low trophic level and to a juvenile stage in natural succession. Feeding, prolificacy and the survival curve inter alia indicate that sardines and allied species are well adapted to cope with fluctuations. Stable environments are somewhat detrimental to sardines, favouring competition by species better adjusted to more mature ecosysten's. Alternative fluctuations between sardines and these species (anchovy, mackerel, etc.) are related to environmental changes, and free oscillations of the predator/prey type seem to be negligible. Assuming random fluctuations in hatching or in recruiting, the dependence of the actual population upon the same population in the preceding year causes fluctuations in the stock, x~ith rnorc or less regular peaks every four to eight years. The amplitude and ax erage period of such fluctuations is related to properties of populations. When composed of a higher proportion of old specin~cns
345
MADANMOHANRAO, G., and K. PAMPAPATH1 RAO, 1962. Oxygen consumption in a brackish water crustacean, Sesarma plicatum (Latreille) and a marine crustacean, Lepas anserifera L. Crustaceana, 4 (l): 75-81. Der Sauerstoffverbrauch des Brackwasserkrebses Sesarma plicatum wurde ermittelt in Leitungswasser, sowie in 25%, 50%, 75% und 100% Meerwasser (Mw). Der Sauerstoffverbrauch war am geringsten in 50% Mw (dem nattirlichen Medium des Versuchstieres) und stieg an in Salzgehalten tiber oder unter 50% mit Maximalwerten im Leitungswasser. Kleinere Individuen zeigten einen st~irkeren Anstieg im Sauerstoffverbrauch nach Ver/inderung des Salzgehaltes als gr/Sssere. Lepas anserifera, ein mariner Cirripedier, wurde in ahnlicher Weise untersucht, und zwar in 25%, 50%, 75%, 100%, 125% und 150% Mw. In 25°0 und in 150% wurden abnormal niedrige Respirationswerte erhalten und die Versuchstiere starben schliesslich. Innerhalb der anderen Salzgehaltsstufen (50 bis 125% Mw) war der Sauerstoffverbrauch am niedrigsten in 100°o Mw (dem natiirlichen Medium des Cirripediers). Der Verbrauch erh6hte oder erniedrigte sich mit steigendem (125% M w ) o d e r fallendem (75%; 50% Mw)Salzgehalt. Diese Ver/inderungen der Stoffwechselintensit/it in verschiedenen Salzgehalten werden gedeutet als Stoffwechselkompensationen : die Versuchstiere zeigen den geringsten Sauerstoffverbrauch in iherem nattirlichen Medium. MAHADEVA, N., 1962. Preliminary report on the experiments with Marutoku-B net and a 45 cm x 90 cm net of No. 0 bolting silk off Trincomalee, Ceylon, during October 1960. lndo-Paci/w/-Tsh. Council, FAO, Proc., 9th Sess., (2/3): 17-24. Comparative studies with the Marutoku-B net and another 45 cm. net of different construction revealed that the Japanese net collected more plankton per cubic meter of water filtered, although filtering a smaller volume o f water. Descriptions of the two nets, and of the methods employed in operating the nets, removing and treating the plankton and of the problems encountered are given. MAKSIMOV, I. V., and V. N. VOROB'YEV,1961. The study of deep currents in the Antarctic Ocean. Abstract : Sov.-Bloc Res. Geophy. Astron. Space, 1962 (42): 7. JPRS 15,068 OTS 61-11147-42. A method for studying deep currents is described and applied to data previously collected in the Antarctic Ocean. This modified ' differential' method is as follows : the electromagnetic method is used to measure currents at the surface and the dynamic method is used to compute movements of deep water relative to the surface. The deep current is determined as the vector difference between the surface current and the current computed for a depth relative to the surface. This work is done in a 'dynamic square' formed by a closed line made up of four cross sections, along which currents are continuously recorded by the electromagnetic method. The sides of the ' square ' should be 30 miles in length. An example of the application of the method is given. The location of the stations used is shown in Figure 2. Curves o f the vertical distribution of current velocity (0-3000 m) are shown in Figure 3 ; Table 1 gives data on deep currents in this area (0-2000 and 3000 m).
Byull. Soy. Antark. Eks., 31: 35-39.
MANGELSDORF, P. C., JR., 1962. The world's longest salt bridge. Mar. Sci. lnstrum., Instrum.
Soc., Amer., Plenum Press, N.Y., 1 : 173-185. A variation of the Geomagnetic Electrokinetograph has been developed in which the electrodes remain aboard ship immersed in sea water at constant composition and temperature. The electrical connection to the sea is made with lengths of polyethylene tubing filled with sea water. This arrangement greatly reduces the sensitivity of the system to gradients of salinity and temperature in the sea. It also permits a direct electrode zero by means of a sea water shunt between the two electrodes. MARGALEF, R., 1962. Fluctiones en abundancia y asequibilidad causadas por factores bioticos.
Methodological Paper, No. 1 : 1265-1285. In the study of fluctuations due to biotic factors it may be useful to replace the usual way of assessing separately the effects o f different factors on the populations by a more synthetic approach, starting from the consideration of the whole ecosystem whose different structural elements (niches) are linked by feedback relations. A number of properties common to such systems can be applied automatically in any special case. Fluctuations may be internal to the ecosystem and then related only to availability, or they may mean a change in the composition of populations, as free oscillations (predator,' prey oscillations) or as forced fluctuations imposed directly or indirectly by environmental (rhythmic) changes. Sardines and related species belong to a low trophic level and to a juvenile stage in natural succession. Feeding, prolificacy and the survival curve inter alia indicate that sardines and allied species are well adapted to cope with fluctuations. Stable environments are somewhat detrimental to sardines, favouring competition by species better adjusted to more mature ecosysten's. Alternative fluctuations between sardines and these species (anchovy, mackerel, etc.) are related to environmental changes, and free oscillations of the predator/prey type seem to be negligible. Assuming random fluctuations in hatching or in recruiting, the dependence of the actual population upon the same population in the preceding year causes fluctuations in the stock, x~ith rnorc or less regular peaks every four to eight years. The amplitude and ax erage period of such fluctuations is related to properties of populations. When composed of a higher proportion of old specin~cns