Osmoregulatory capacity of the Cladocera

Аладин, Н. В.; Potts, W. T. W.

doi:10.1007/bf00389810

Cited by 84 publications

(76 citation statements)

References 36 publications

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“…Aladin and Potts (1995) suggest that the closed brood chamber of B. longimanus is an adaptation that improves osmoregulatory control of the embryonic environment. Thus, despite the species' current preference for freshwater, salinity exposure may have been relevant in the evolution of B. longimanus and a condition that is not stressful to its resting egg.…”

Section: Discussionmentioning

confidence: 99%

Effects of chemical and physical conditions on hatching success of Bythotrephes longimanus resting eggs

Branstrator

Shannon

Brown

et al. 2013

Limnology & Oceanography

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Dormant eggs of zooplankton are considered to be tolerant of harsh environmental conditions, yet lethal thresholds of exposure have rarely been determined. We describe 3 yr of dose-response experiments that evaluate hatching success of the resting egg of Bythotrephes longimanus (Cladocera: Cercopagidae) in response to salinity, chlorination, heat, desiccation, and freezing. There was no decline in hatching success in response to salinity (up to 4 weeks at 35 g L 21 salt) or chlorination (including up to 5 min at 3400 mg L 21 chlorine). In response to heat there was an interaction between time and temperature; hatching occurred after exposure to 40uC for 1 min, 5 min, or 10 min but declined with the two longer exposures. Hatching also occurred after exposure to 50uC for 1 min, but no hatching followed exposure to 50uC for 5 min or to higher temperatures for 1 min. In response to desiccation at 17uC, exposure for # 4 h had no effect on hatching but $ 6 h resulted in no hatching. When frozen, hatching success depended on whether eggs were frozen in water or without water. Collectively, the results are congruent with an evolutionary origin of B. longimanus in permanent, euryhaline basins. The results advance our understanding of dispersal limits of B. longimanus, including vector potential, and may inform management practices for reducing range expansion of B. longimanus by humans.Crustacean zooplankton that inhabit temporally variable environments commonly have life cycles that alternate between active and dormant stages (Hairston 1996;Hairston and Cá ceres 1996;Gyllströ m and Hansson 2004). The dormant stage is more durable and able to withstand conditions that are unfavorable or lethal to the active stage (Panov and Cá ceres 2007). For example, experiments and direct observations demonstrate that dormant stages can tolerate exposures to a variety of adverse environmental conditions, including desiccation (Brewer 1964;

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Section: Discussionmentioning

confidence: 99%

Effects of chemical and physical conditions on hatching success of Bythotrephes longimanus resting eggs

Branstrator

Shannon

Brown

et al. 2013

Limnology & Oceanography

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“…Tolerance to salinity can vary greatly among species and also depends on ionic composition (Cañedo-Argü-elles et al, 2013) and temperature (Aladin & Potts, 1995;Brucet et al, 2010). However, increases in salinity cause a decrease in the densities of most organism groups due to osmotic stress, as shown by the literature review.…”

Section: Effects Of Changes In Salinity/conductivitymentioning

confidence: 99%

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

et al. 2015

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According to the Intergovernmental Panel on Climate Change report released in September 2014, unprecedented changes in temperature and precipitation patterns have been recorded globally in recent decades and further change is predicted to occur in the near future, mainly as the result of human activity. In particular, projections show that the Mediterranean climate zone will be markedly affected with significant implications for lake water levels and salinity. This may be exacerbated by increased demands for irrigation water. Based on long-term data from seven lakes and reservoirs covering a geographical gradient of 52°of latitudes and a literature review, we discuss how changes in water level and salinity related to climate change and water abstraction affect the ecosystem structure, function, biodiversity and ecological state of lakes and reservoirs. We discuss mitigation measures to counteract the negative effects on ecological status that are likely to result from changes in climate and water abstraction practices. Finally, we highlight research required to improve knowledge of the impacts of anthropogenically induced changes on lake water level and consequent changes in salinity.

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“…Embryonic dorsal organs (and dorsolateral organs) have been described in hyper-regulating non-decapodan crustaceans (Anderson, 1973;Fioroni, 1980;Martin and Laverack, 1992), including isopods (Strömberg, 1972), amphipods (Meschenmoser, 1989;Morritt and Spicer, 1995;Morritt and Spicer, 1996) and branchiopods (Aladin and Potts, 1995). Their ultrastructure is often suggestive of active ion transport and in Orchestia the dorsal organ stains with silver (Meschenmoser, 1989).…”

Section: Sites Of Uptake and Excretion Of Water And Salts In Embryosmentioning

confidence: 99%

“…Dorsal organs, also referred to as nuchal or neck organs, are present in other larval and adult crustaceans, notably in the nauplii of branchiopods. Their homology with embryonic dorsal organs is uncertain but they are believed to function as either ionoregulatory or sensory organs (Martin and Laverack, 1992;Aladin and Potts, 1995).…”

Section: Introductionmentioning

confidence: 99%

Ontogeny of osmoregulation in embryos of intertidal crabs(Hemigrapsus sexdentatusandH. crenulatus, Grapsidae,Brachyura): putative involvement of the embryonic dorsal organ

Seneviratna

Taylor

2006

Journal of Experimental Biology

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SUMMARY This study examined whether the existence of hyperosmotic internal fluids in embryos of euryhaline crabs (Hemigrapsus sexdentatus and H. crenulatus) in dilute seawater reflects osmotic isolation due to impermeability of the egg envelope, as proposed for other decapods, or active osmoregulation. When ovigerous crabs with eggs at gastrula stage were transferred from 100% seawater (osmolality 1000 mmol kg–1) to 50% seawater, embryogenesis and hatching of zoea were completed normally, but were delayed. Hatching failed if the transfer to 50% seawater occurred before gastrulation, and embryogenesis was abnormal in 25% seawater. In 100%seawater, embryos at all stages were internally hyperosmotic by 150–250 mmol kg–1. On transfer to 50% seawater, osmolality initially decreased but remained 200–350 mmol kg–1 hyperosmotic to the medium for several weeks until hatching. High efflux rates of tritium-labelled water (t1/2 16–75 min)and 22Na (t1/2 109–374 min) from H. crenulatus embryos were inconsistent with the osmotic isolation hypothesis. It is concluded that post-gastrula embryos were actively hyper-osmoregulating. The diffusional water permeability of the embryos decreased during development while the sodium efflux rate increased 10-fold. Very rapidly exchanging pools of water and sodium (t1/2 a few seconds to minutes) probably corresponded to peri-embryonic fluid and implied that the egg envelope was a negligible barrier to diffusion of water and salts. Higher Na+/K+-ATPase activities in late embryos of H. crenulatus incubated in 50% seawater than in embryos incubated in full strength seawater were consistent with an acclimation response. An area of the embryonic surface located over the yolk in the region of the embryonic dorsal organ stained with AgNO3. Staining appeared at gastrulation, persisted throughout development and was lost at hatching. Deposits of AgCl between the outer and inner membranes, identified by X-ray microanalysis, suggest that the dorsal organ was a site of chloride extrusion. A model for osmoregulation in post-gastrula embryos is proposed: osmotic uptake of water is balanced by excretion of water and salts via the dorsal organ and salt loss is balanced by active uptake over the general embryonic ectoderm.

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Osmoregulatory capacity of the Cladocera

Cited by 84 publications

References 36 publications

Effects of chemical and physical conditions on hatching success of Bythotrephes longimanus resting eggs

Effects of chemical and physical conditions on hatching success of Bythotrephes longimanus resting eggs

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

Ontogeny of osmoregulation in embryos of intertidal crabs(Hemigrapsus sexdentatusandH. crenulatus, Grapsidae,Brachyura): putative involvement of the embryonic dorsal organ

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