Volume regulation in aquatic invertebrates

Oglesby, Larry C.

doi:10.1002/jez.1402150307

Cited by 49 publications

(18 citation statements)

References 62 publications

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“…The medical leech, Hirudo medicinalis Linnaeus, 1758, was found to occasionally invade brackish water habitats. Many studies point out that the body fluid of other marine invertebrates is also normally slightly hyperosmotic to the surrounding medium (Dice, 1969;Pierce, 1970;Oglesby, 1973Oglesby, , 1981. Our measurements for E. albidus (both of terrestrial and marine origin) and for H. costata are in agreement with this, apparently, general hyperosmoticity, that is maintained at least in lower salinities.…”

Section: Low Salinity Rangesupporting

confidence: 87%

Osmoregulation in two aquatic oligochaetes from habitats with different salinity and comparison to other annelids

Generlich

Giere

1996

Hydrobiologia

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The osmoregulatory capacity of two oligochaete species, Enchytraeus albidus Henle, 1837, and Heterochaeta costata (Claparede, 1863), was investigated by direct measurements of the osmolality of the coelomic fluid. Terrestrial and marine (28%o S) populations of Enchytraeus albidus and a brackish water population (14%o S) of H. costata were used in the study. The range of salinity acclimation investigated was 0-40%o. The response to osmotic stress was measured (a) after a long-term maintenance (> 14 days) in various salinities (E. albidus only), and (b) after a hyperosmotic shock as a short-term time-course sequence. The rate of water loss following a hyperosmotic shock was measured for E. albidus. Long-term acclimation. E. albidus maintained a hyperosmotic coelomic fluid over all salinities tested. In low salinities the osmolality of the coelomic fluid of the marine population was significantly higher than that of the terrestrial population. Possible genetic discrepancies or long-term acclimation may account for this difference. The coelomic fluid of H. costata was hyperosmotic at 15%o S and isoosmotic at 30%o S. Short-term acclimation (hyperosmotic shock). Both species investigated, kept at 15%o S and then exposed to a salinity of 30%o, showed fast responses: within the first two hours the internal concentrations were adjusted to the new external condition with only small subsequent changes. Regulation of the body-water content after an exposure to a hyperosmotic shock was much slower: individuals of terrestrial E. albidus, acclimated for two weeks to either 0%o or 15%o S, had the same water content; hence, they showed a 100% regulation. However, after exposure to 30%oo S, a 100% regulation was still not attained 4 days after the hyperosmotic shock. Enchytraeus albidus is capable of actively reducing water loss following the hyperosmotic shock: the observed loss of water was only 40% of that expected for a passive osmotic flow. The observed reactions are compared with those in other annelids. It seems that an active transport of ions combined with a changeable permeability of the body wall play a major role in the regulation of body fluids.

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Section: Low Salinity Rangesupporting

confidence: 87%

Osmoregulation in two aquatic oligochaetes from habitats with different salinity and comparison to other annelids

Generlich

Giere

1996

Hydrobiologia

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“…We will refer to the former as long term volume regulation and the latter as short term volume regulation. Measurement of the limitation of water uptake which constitutes short term volume regulation generally requires comparison of an observed volume increase with the potential increase in a true osmometer, calculated from the solute and water content of worms in normal sea water (Machin, 1975;Oglesby, 1981). Although we have not measured solute content in Paranemertes .it is clear that short term volume regulation is occurring during exposure to 75% sea water, because intact worms gain less weight than operated worms.…”

Section: Volume Regulationmentioning

confidence: 97%

“…Thus the ecologically relevant period for studies of volume regulation is the first 12 hours of exposure to a change in salinity. Oglesby (1981) distinguishes two types of volume regulation during exposure of an organism to hetero-osmotic media. The traditional concept of volume regulation in hypo-osmotic media refers to the gradual restoration of the original volume following the maximum increase.…”

Section: Volume Regulationmentioning

confidence: 99%

The role of nemertean cerebral organs in salinity stress tolerance re‐examined inParanemertes peregrinacoe (hoplonemertea: Monostilifera)

Amerongen

Chia

1983

Marine Behaviour and Physiology

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The role of the cerebral organs of Paranemertes in salinity stress tolerance was investigated by measuring the effect of cerebral organ removal on volume regulation, and by observing the effects of hypo-osmotic media on the cytology of the cerebral organs. Removal of the cerebral organs decreases the capacity for volume regulation, however, a similar change is seen in sham-operated worms, indicating that the decreased capacity for regulation is due to the operation itself and not to interference with a physiological role of the cerebral organs. Cytological changes caused by in vivo exposure to dilute sea water are similar to those seen in worms fixed in hypo-osmotic fixative and therefore do not likely represent a coordinated response of the organs to salinity stress. Also, no exchange of material between the cerebral organs and the vascular system, as reported in some other species (Ling, 1970;Ferraris, 1979), was observed. We conclude that in Paranemertes, the cerebral organs are not involved in osmoregulation.t Present address:

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“…Care must be exercised during the processing of samples because it may result in unwanted effects. Because marine invertebrates are generally hyperosmotic to their environment (Pierce 1970;Oglesby 1981), their biomass is made up of a large quantity of inorganic ions. Hyperosmoticity and hygroscopicity together probably influence the weight of marine invertebrate larvae and may be of particular importance to those stages that experience marked ionic fluxes such as during fertilization.…”

Section: Effects Of Drying and Ashing On The Weight Of Inorganicmentioning

confidence: 99%

A test of the ashߚfree dry weight technique on the developmental stages of Patiriellaspp. (Echinodermata: Asteroidea)

Moreno

Selvakumaraswamy

Byrne

et al. 2001

Limnology & Oceanography

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Determination of the ashߚfree dry weight (AFDW) of marine specimens requires samples to be rinsed, soaked, and centrifuged. Problems associated with this technique were examined with the developmental stages of seastar species (Patiriella) with different modes of development. The influence of three rinsing solutions (ammonium formate [AF], filtered seawater [FSW], and reverse osmosis water [RO]) was assessed. The hypothesis that the AFDW technique is a measure of organic material was addressed by drying inorganic salts. Developmental stages of Patiriella calcar rinsed in FSW were twice as heavy as those rinsed in RO or AF, indicating that samples should be rinsed in RO or AF before weighing. Soaking treatments had a significant effect on the AFDW of samples of P. calcar (planktonic developer), indicating that the rinsing period should be brief. Zygotes of Patiriella regularis (planktonic developer) were significantly heavier than ova or gastrulae, regardless of treatment. In contrast, there were no significant differences in the AFDW of any stages or treatments of Patiriella exigua (benthic developer). This may be due to the presence of a modified fertilization envelope, which protects these benthic embryos. Inorganic salts with water of crystallization and FSW lost 20–75% and 14% of their dry weight, respectively, after ashing. We propose that salt ions may retain water, which does not evaporate during drying but is lost during ashing, resulting in the overestimation of sample AFDW. If a similar process occurs in the developmental stages of marine invertebrates, changes in the intracellular ionic composition through development may result in inaccurate estimates of biomass.

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Volume regulation in aquatic invertebrates

Cited by 49 publications

References 62 publications

Osmoregulation in two aquatic oligochaetes from habitats with different salinity and comparison to other annelids

Osmoregulation in two aquatic oligochaetes from habitats with different salinity and comparison to other annelids

The role of nemertean cerebral organs in salinity stress tolerance re‐examined inParanemertes peregrinacoe (hoplonemertea: Monostilifera)

A test of the ashߚfree dry weight technique on the developmental stages of Patiriellaspp. (Echinodermata: Asteroidea)

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