Seasonal Variation in Physiological Energetics of Mytilus Edulis and Cerastoderma Edule of Different Size Classes

1997 ◽  
Vol 77 (3) ◽  
pp. 817-838 ◽  
Author(s):  
A.C. Smaal ◽  
A.P.M.A. Vonck ◽  
M. Bakker
Keyword(s):  
Body Weight ◽  
Seasonal Variation ◽  
Mytilus Edulis ◽  
Clearance Rate ◽  
Sea Water ◽  
Stepwise Multiple Regression ◽  
Reproductive Condition ◽  
Cerastoderma Edule ◽  
Size Classes ◽  
Respiration Rates

Seasonal variation of clearance, absorption and respiration rates of mussels Mytilus edulis (Mollusca: Bivalvia) and cockles Cerastoderma edule (Mollusca: Bivalvia) of various size classes have been measured under ambient temperature and sea-water conditions. Food availability was kept almost constant during the measurements.Allometric body weight coefficients were bcl=0.5 for clearance and about br=0.7 for respiration rate of both species. Stepwise multiple regression suggested no relation for clearance rate of mussels with temperature and reproductive condition throughout the year. Respiration rates of mussels were highest during the reproductive period. Excretion rate was measured for mussels only and showed an allometric coefficient of bex=0.7 and an increase with temperature in spring. For cockles a significant relation of clearance rate, body weight and temperature was observed; at low temperature, clearance rates of small animals were more reduced than for larger animals. Respiration rates of cockles showed a significant relationship with temperature and reproductive condition.

The effects of lowered salinity upon Branchiostoma lanceolatum from the English Channel

1981 ◽  
Vol 61 (3) ◽  
pp. 685-689 ◽  
Author(s):  
J. Binyon
Keyword(s):  
Body Weight ◽  
Osmotic Stress ◽  
Sea Water ◽  
English Channel ◽  
Sharp Threshold ◽  
Branchiostoma Lanceolatum

Previous work has indicated that, although in possession of numerous supposedly osmoregulatory structures, Branchiostoma lanceolatum from the English Channel is unable to regulate its body weight in diluted sea water. In vitro measurements of the rate of flagella activity in those organs similarly indicates no increase under hypo-osmotic stress. There is however quite a sharp threshold around 18‰, below which flagella activity ceases quite abruptly. A similar situation obtains with the gill cilia although the animal can remain alive at these salinities for a period of several weeks.

Urinary Bladder Volume and the Reabsorption of Water from the Urine of Crabs

1974 ◽  
Vol 60 (1) ◽  
pp. 167-181
Author(s):  
J. A. RIEGEL ◽  
A. P. M. LOCKWOOD ◽  
J. R. W. NORFOLK ◽  
N. C. BULLEID ◽  
P. A. TAYLOR
Keyword(s):  
Body Weight ◽  
Urinary Bladder ◽  
Blood Volume ◽  
Ethacrynic Acid ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Bladder Volume ◽  
Active Secretion ◽  
51Cr Edta

1. Measurements have been made to determine the blood volume, bladder volume, clearance of 131I-sodium diatrizoate and U/H for diatrizoate in the crabs Carcinus maenas and Macropipus (Portunus) depurator. 2. Observed values of clearance blood volume and bladder volume in the two species at 18 °C were: Clearance (as % blood volume per day), Macropipus 56.1±14.5; Carcinus 27.1±5.8; Blood volume (as % body weight), Macropipus 21.0±4.0; Carcinus 19.2±3.0; Bladder volume (as % blood volume), Macropipus 12.1 ±5.0; Carcinus 11.0±8.0. 3. It is shown that the measured U/H differs from that to be expected if no reabsorption of water or secretion of diatrizoate occurs. 4. 14C-inulin and 51Cr-EDTA are excreted in an essentially similar manner to 131I-diatrizoate by Carcinus, implying that any active secretion of diatrizoate must be small in magnitude. 5. Injections of ethacrynic acid decrease the U/H ratio for diatrizoate relative to that in control Carcinus injected with sea water. In some Carcinus the concentration of diatrizoate in the urine comes to exceed that initially present in the blood. Both these points are taken, with 3, as support for the conclusion that water can be withdrawn from the primary urine of Carcinus.

Sodium Regulation and Adaptation to Fresh Water in Gammarid Crustaceans

1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Body Weight ◽  
Fresh Water ◽  
Body Surface ◽  
Sea Water ◽  
Sodium Concentration ◽  
The Body ◽  
Outward Diffusion ◽  
Gammarus Zaddachi ◽  
Freshwater Habitats ◽  
Sodium Regulation

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.

The opening response of mussels (Mytilus edulis) exposed to rising sea-water concentrations

1981 ◽  
Vol 61 (3) ◽  
pp. 667-678 ◽  
Author(s):  
John Davenport
Keyword(s):  
Mytilus Edulis ◽  
Sea Water ◽  
External Medium ◽  
Mantle Cavity ◽  
Low Salinity ◽  
Medium Exchange ◽  
Mantle Edge

When exposed to water of low salinity specimens of Mytilus edulis L. keep their shell valves tightly closed; they do not gape periodically to test the external medium. Exchange of salts and water between the mantle cavity and the environment is thus minimized. Rising salinities are registered by diffusion of salts to the tentaculate portion of the inhalent siphon and not to any other portion of the mantle edge or to any more deeply located structures.

scholarly journals Changes in the thyroid gland during the reproductive cycle of the male vespertilionid bat, Scotophilus heathi

1998 ◽  
Vol 58 (4) ◽  
pp. 707-716 ◽  
Author(s):  
A. KRISHNA ◽  
K. SINGH
Keyword(s):  
Body Weight ◽  
Seasonal Variation ◽  
Thyroid Gland ◽  
Seasonal Change ◽  
Reproductive Cycle ◽  
The Body ◽  
Winter Dormancy ◽  
High Concentration ◽  
Positive Correlation ◽  
Low Concentration

The aim of present study was to compare the changes in thyroid gland with the reproductive cycle of S. heathi. Thyroid showed marked seasonal variation in weight, quantity of colloid and follicular epithelial height, suggesting the thyroid gland to be inactive during quiescence and winter dormancy and active during the time of recrudescence and breeding similarly to the testicular cycle. Plasma thyroxin (T4) concentration showed a significant seasonal change with high concentration during breeding and post-breeding and low concentration during quiescence. However, the T4 concentration increased from breeding to post-breeding phase, when the testes weight was declining. It is suggested that in S. heathi the positive correlation between thyroid and testicular cycles occurs only during the phases of the reproductive cycle when the body weight and testicular activity are also closely correlated.

Photoperiod synchronizes reproduction and growth in the southern flying squirrel,Glaucomys volans

1990 ◽  
Vol 68 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Theresa M. Lee ◽  
Irving Zucker
Keyword(s):  
Body Weight ◽  
Reproductive Condition ◽  
Glaucomys Volans ◽  
Flying Squirrel ◽  
Seasonal Rhythms ◽  
Flying Squirrels ◽  
Body Weights ◽  
Natural Photoperiod ◽  
Ad Libitum ◽  
Southern Flying Squirrel

Southern flying squirrels were housed in a simulated natural photoperiod for 40°N latitude and held at a constant temperature of 23 °C with food and water provided ad libitum. Body weight and reproductive condition were monitored weekly for 2 years. Males were in reproductive condition between January and mid-August and females were in estrus from late February to mid-April and again from mid-June until early August. Young were conceived during both estrous periods and several squirrels produced two litters in the same year. Minimum body weights were recorded in adults in mid-October each year. Pups born in the spring grew more rapidly than those from summer litters, and reached puberty at 2.5 months as compared with 6–8 months of age for the summer litters. Several seasonal rhythms appear to be controlled by photoperiod in this species.

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