Volume regulation in Nereis diversicolor—I. the steady state

Structure and function of the anal sacs ofBonellia viridis(Echiura: Bonelliidae)

“…In Bonellia one estimate of the total number was 17000. Clearance per funnel was, therefore, 1-3 nl h" 1 , which is lower than the 54 nl h" 1 calculated on the basis of 140 nephridia present in Nereis (Fletcher, 1974). As measured in fixed sectioned material the luminal diameter of the funnel in Bonellia is 5 fiva.…”

“…The total filtration rate of the anal sacs of Bonellia can be compared with published rates of the urine flow of annelid nephridia. Smith (1970), calculated a rate of 3-0 ml kg" 1 h" 1 , and Fletcher (1974), a mean of 15 ml kg" 1 h" 1 , in Nereis diversicolor in 100% sea water. These were both indirect estimates using, in the former diffusional and, in the latter, osmotic permeabilities to water.…”

Structure and function of the anal sacs ofBonellia viridis(Echiura: Bonelliidae)

“…In Bonellia one estimate of the total number was 17000. Clearance per funnel was, therefore, 1-3 nl h" 1 , which is lower than the 54 nl h" 1 calculated on the basis of 140 nephridia present in Nereis (Fletcher, 1974). As measured in fixed sectioned material the luminal diameter of the funnel in Bonellia is 5 fiva.…”

“…The total filtration rate of the anal sacs of Bonellia can be compared with published rates of the urine flow of annelid nephridia. Smith (1970), calculated a rate of 3-0 ml kg" 1 h" 1 , and Fletcher (1974), a mean of 15 ml kg" 1 h" 1 , in Nereis diversicolor in 100% sea water. These were both indirect estimates using, in the former diffusional and, in the latter, osmotic permeabilities to water.…”

Euryhalinity of subtropical marine and estuarine polychaetes evaluated through carbonic anhydrase activity and cell volume regulation

“…However, if it occurred (see discussion of CAA for this species below), it was a partial response, and salt continued to be absorbed, resulting in a hyperosmotic hemolymph with respect to the water. In addition, a hyperosmotic hemolymph in relation to the water can be a result of a relatively low permeability to water and salt, and perhaps the production of a dilute urine (Oglesby, 1965b, 1968; Doneen & Clark, 1974; Fletcher, 1974a; Oglesby, 1981; Larsen et al, 2014). Further studies should help to elucidate the mechanisms and strategies employed by these euryhaline worms.…”

Osmoregulation and Excretion

“…The magnitude of these diffusive fluxes depends on the scale of the change in the ambient osmolality. Reductions in the permeability of the body wall to water have been reported in both molluscs (406,1491) and polychaetes (539) exposed to reduced osmotic concentrations. This mechanism would slow the rate of water influx and provide the animal with more time to compensate.…”

Structure and function of the anal sacs ofBonellia viridis(Echiura: Bonelliidae)

“…In Bonellia one estimate of the total number was 17000. Clearance per funnel was, therefore, 1-3 nl h" 1 , which is lower than the 54 nl h" 1 calculated on the basis of 140 nephridia present in Nereis (Fletcher, 1974). As measured in fixed sectioned material the luminal diameter of the funnel in Bonellia is 5 fiva.…”

“…The total filtration rate of the anal sacs of Bonellia can be compared with published rates of the urine flow of annelid nephridia. Smith (1970), calculated a rate of 3-0 ml kg" 1 h" 1 , and Fletcher (1974), a mean of 15 ml kg" 1 h" 1 , in Nereis diversicolor in 100% sea water. These were both indirect estimates using, in the former diffusional and, in the latter, osmotic permeabilities to water.…”

Euryhalinity of subtropical marine and estuarine polychaetes evaluated through carbonic anhydrase activity and cell volume regulation

“…However, if it occurred (see discussion of CAA for this species below), it was a partial response, and salt continued to be absorbed, resulting in a hyperosmotic hemolymph with respect to the water. In addition, a hyperosmotic hemolymph in relation to the water can be a result of a relatively low permeability to water and salt, and perhaps the production of a dilute urine (Oglesby, 1965b, 1968; Doneen & Clark, 1974; Fletcher, 1974a; Oglesby, 1981; Larsen et al, 2014). Further studies should help to elucidate the mechanisms and strategies employed by these euryhaline worms.…”

Osmoregulation and Excretion

“…The magnitude of these diffusive fluxes depends on the scale of the change in the ambient osmolality. Reductions in the permeability of the body wall to water have been reported in both molluscs (406,1491) and polychaetes (539) exposed to reduced osmotic concentrations. This mechanism would slow the rate of water influx and provide the animal with more time to compensate.…”

Structure and function of the anal sacs ofBonellia viridis(Echiura: Bonelliidae)

“…In Bonellia one estimate of the total number was 17000. Clearance per funnel was, therefore, 1-3 nl h" 1 , which is lower than the 54 nl h" 1 calculated on the basis of 140 nephridia present in Nereis (Fletcher, 1974). As measured in fixed sectioned material the luminal diameter of the funnel in Bonellia is 5 fiva.…”

“…The total filtration rate of the anal sacs of Bonellia can be compared with published rates of the urine flow of annelid nephridia. Smith (1970), calculated a rate of 3-0 ml kg" 1 h" 1 , and Fletcher (1974), a mean of 15 ml kg" 1 h" 1 , in Nereis diversicolor in 100% sea water. These were both indirect estimates using, in the former diffusional and, in the latter, osmotic permeabilities to water.…”

Euryhalinity of subtropical marine and estuarine polychaetes evaluated through carbonic anhydrase activity and cell volume regulation

“…However, if it occurred (see discussion of CAA for this species below), it was a partial response, and salt continued to be absorbed, resulting in a hyperosmotic hemolymph with respect to the water. In addition, a hyperosmotic hemolymph in relation to the water can be a result of a relatively low permeability to water and salt, and perhaps the production of a dilute urine (Oglesby, 1965b, 1968; Doneen & Clark, 1974; Fletcher, 1974a; Oglesby, 1981; Larsen et al, 2014). Further studies should help to elucidate the mechanisms and strategies employed by these euryhaline worms.…”

Osmoregulation and Excretion

“…The magnitude of these diffusive fluxes depends on the scale of the change in the ambient osmolality. Reductions in the permeability of the body wall to water have been reported in both molluscs (406,1491) and polychaetes (539) exposed to reduced osmotic concentrations. This mechanism would slow the rate of water influx and provide the animal with more time to compensate.…”