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Blood concentrations of Limnoria (Isopoda) in relation to salinity
Oceanographic Abstracts
581
EAGLESFIELD C. C., 1964. Backscatter of sound from the sea bottom. J. Acoust. Soc. Amer., 36 (6): 1217. Recently published measurements of backscatter from the sea bottom seem to be explained by an inverse-square probability density of surface inclinations. EDWARDS C., 1964. On the hydroids and medusae Bougainvillia pyramidata and B. muscoides.
J. Mar. Biol. Ass., U.K., 44 (3): 725-750. The hitherto unknown hydroid of the anthomedusa Bougainvillia pyramidata was found in the Firth of Clyde, and medusae from it were reared to maturity. The hydroid and the stages of development of the medusa are described and figured, and the species is compared with B. ramosa. The seasonal occurrence and distribution of the medusa are discussed. The hydroid Bougainvillia muscoides (M. Sars) was also found in the Firth of Clyde. Medusae have been reared from it, and a description, with figures, of the stages of development is given. The specimens found in 1901 in this area and described by Browne as Thamnitis sp. are shown to be young medusae of B. muscoides. The geographical and bathymetric distribution of the species and the seasonal occurrence of the medusa are described. ELTRINGHAM S. K., 1964. Blood concentrations o f Limnoria (Isopoda) in relation to salinity.
J. Mar. Biol. Ass., U.K., 44 (3): 675-683. Freezing-point measurements were made of blood samples taken from specimens of the marine wood-boring isopod Limnoria that had been exposed to seawater of various salinities for 2-3 days. Most of the work was done with L. (L.) tripunctata Menzies, but some preliminary experiments were carried out with L. (L.) lignorum (Rathke) and L. (L.) quadripunctata Holthuis. The freezing point of the blood averaged 0-17°C above that of the external medium in both hypo- and hyperosmotic environments. In the absence of any obvious factor which could explain this discrepancy, it is assumed that Limnoria has a certain degree of control over its blood concentrations. Further experiments showed that the blood concentration fell as soon as the animal was introduced to the reduced salinity and levelled off at the hyperosmotic value within a few hours. There was some evidence of a periodicity in the osmoregulation. The possible energy.tics of osmoregulation in Limnoria are discussed and it is concluded that the amount of energy utilized in the process is unlikely to make any significant inroad into the energy resources available for boring activity. ENOO H., 1963. On the characteristics of the sea wave at Ty6si I(6 and its neighborhood. (In Japanese; Eng. abstr.). Hydrogr. Bull., Tokyo, No. 73 (Publ. No. 981): 17-28. Nearshore wave observations were carried out, with the thermopile wave recorder, from 13-26 October 1958, at TyOsi K6, to study the characteristics of the wave, in particular those generated by the typhoon. (I) The significant wave height was about l m and its period about 10sec, for wind speeds from 3 m/sec to 8 m/sec. The height and period had no relation with the wind direction. (2) When a typhoon was coming up to the observation station, the significant wave height increased rapidly and the rate of increase was 0"9 m/hr at the maximum, but its period decreased slowly. The significant wave height was about 7"5 m, and its period about 8 sec for the wind speed 25 m/sec. (3) The energy spectra when the typhoon was approaching have two peaks indicating the interference of two wave groups and the phenomenon of beat. The maximum peak of the spectrum moved from the long period to the short period zone as the typhoon came nearer. ENGEL A. E. J. and C. G. ENGEL,1964. Composition of basalts from the Mid-Atlantic Ridge.
Science, 144 (3624): 1330--1333. Studies of volcanic rocks in dredge hauls from the submerged parts of the Mid-Atiantic Ridge suggest that it consists largely of tholeiitic basalt with low values of K, Ti, and P. In contrast, the volcanic islands which form the elevated caps on the Ridge are built of alkali basalt with high values ofTi, Fe 3, P, Na, and K. This distinct correlation between the form of the volcanic structures, elevation above the sea floor, and composition suggests that the islands of alkali basalt are derived from a parent tholeiitic magma by differentiation in shallow reservoirs. The volume of low-potassium tholeiites along the Md-Atlantic Ridge and elsewhere in the oceans appears to be many times that of the alkali basalts exposed on oceanic islands. Tholeiitic basalts with about 0.2 K~.O appear to be the primary and predominant magma erupted on the oceanic floor. ENGELEN G. B., 1964. A hypothesis on the origin of the Bermuda Rise. Tectonophysics, Elsevier, 1 (1): 85-93. From a review of the principal data on the Bermuda Rise, the following working hypothesis on the genesis of the Bermuda Rise is proposed : A differential drift of the North American continent since the Mesozoic caused a geotectonic exposure of the sub-Moho level of the American Shield in the newly formed, northwestern Atlantic Ocean. The decrease of pressure in the lee of the drifting continent induced a phase transition
581
EAGLESFIELD C. C., 1964. Backscatter of sound from the sea bottom. J. Acoust. Soc. Amer., 36 (6): 1217. Recently published measurements of backscatter from the sea bottom seem to be explained by an inverse-square probability density of surface inclinations. EDWARDS C., 1964. On the hydroids and medusae Bougainvillia pyramidata and B. muscoides.
J. Mar. Biol. Ass., U.K., 44 (3): 725-750. The hitherto unknown hydroid of the anthomedusa Bougainvillia pyramidata was found in the Firth of Clyde, and medusae from it were reared to maturity. The hydroid and the stages of development of the medusa are described and figured, and the species is compared with B. ramosa. The seasonal occurrence and distribution of the medusa are discussed. The hydroid Bougainvillia muscoides (M. Sars) was also found in the Firth of Clyde. Medusae have been reared from it, and a description, with figures, of the stages of development is given. The specimens found in 1901 in this area and described by Browne as Thamnitis sp. are shown to be young medusae of B. muscoides. The geographical and bathymetric distribution of the species and the seasonal occurrence of the medusa are described. ELTRINGHAM S. K., 1964. Blood concentrations o f Limnoria (Isopoda) in relation to salinity.
J. Mar. Biol. Ass., U.K., 44 (3): 675-683. Freezing-point measurements were made of blood samples taken from specimens of the marine wood-boring isopod Limnoria that had been exposed to seawater of various salinities for 2-3 days. Most of the work was done with L. (L.) tripunctata Menzies, but some preliminary experiments were carried out with L. (L.) lignorum (Rathke) and L. (L.) quadripunctata Holthuis. The freezing point of the blood averaged 0-17°C above that of the external medium in both hypo- and hyperosmotic environments. In the absence of any obvious factor which could explain this discrepancy, it is assumed that Limnoria has a certain degree of control over its blood concentrations. Further experiments showed that the blood concentration fell as soon as the animal was introduced to the reduced salinity and levelled off at the hyperosmotic value within a few hours. There was some evidence of a periodicity in the osmoregulation. The possible energy.tics of osmoregulation in Limnoria are discussed and it is concluded that the amount of energy utilized in the process is unlikely to make any significant inroad into the energy resources available for boring activity. ENOO H., 1963. On the characteristics of the sea wave at Ty6si I(6 and its neighborhood. (In Japanese; Eng. abstr.). Hydrogr. Bull., Tokyo, No. 73 (Publ. No. 981): 17-28. Nearshore wave observations were carried out, with the thermopile wave recorder, from 13-26 October 1958, at TyOsi K6, to study the characteristics of the wave, in particular those generated by the typhoon. (I) The significant wave height was about l m and its period about 10sec, for wind speeds from 3 m/sec to 8 m/sec. The height and period had no relation with the wind direction. (2) When a typhoon was coming up to the observation station, the significant wave height increased rapidly and the rate of increase was 0"9 m/hr at the maximum, but its period decreased slowly. The significant wave height was about 7"5 m, and its period about 8 sec for the wind speed 25 m/sec. (3) The energy spectra when the typhoon was approaching have two peaks indicating the interference of two wave groups and the phenomenon of beat. The maximum peak of the spectrum moved from the long period to the short period zone as the typhoon came nearer. ENGEL A. E. J. and C. G. ENGEL,1964. Composition of basalts from the Mid-Atlantic Ridge.
Science, 144 (3624): 1330--1333. Studies of volcanic rocks in dredge hauls from the submerged parts of the Mid-Atiantic Ridge suggest that it consists largely of tholeiitic basalt with low values of K, Ti, and P. In contrast, the volcanic islands which form the elevated caps on the Ridge are built of alkali basalt with high values ofTi, Fe 3, P, Na, and K. This distinct correlation between the form of the volcanic structures, elevation above the sea floor, and composition suggests that the islands of alkali basalt are derived from a parent tholeiitic magma by differentiation in shallow reservoirs. The volume of low-potassium tholeiites along the Md-Atlantic Ridge and elsewhere in the oceans appears to be many times that of the alkali basalts exposed on oceanic islands. Tholeiitic basalts with about 0.2 K~.O appear to be the primary and predominant magma erupted on the oceanic floor. ENGELEN G. B., 1964. A hypothesis on the origin of the Bermuda Rise. Tectonophysics, Elsevier, 1 (1): 85-93. From a review of the principal data on the Bermuda Rise, the following working hypothesis on the genesis of the Bermuda Rise is proposed : A differential drift of the North American continent since the Mesozoic caused a geotectonic exposure of the sub-Moho level of the American Shield in the newly formed, northwestern Atlantic Ocean. The decrease of pressure in the lee of the drifting continent induced a phase transition