Sodium uptake in different life stages of crustaceans: the water fleaDaphnia magnaStrauss

Abstract

+ /Cl-exchanger. Differential sensitivity of neonates and adults to iono-and osmoregulatory toxicants, such as metals, are discussed with respect to differences in whole-body Na + uptake kinetics, as well as in the mechanisms of Na + transport involved in the whole-body Na + uptake in the two life stages.

An evaluation of biotic ligand models predicting acute copper toxicity to Daphnia magna in wastewater effluent

“…Consequently, the biotic ligand stability constant for sodium potentially incorporates the protective influence of competition for binding, alongside the uptake assistance provided by environmental sodium. Following on from this, Bianchini and Wood [37] identified a typical Michaelis-Menton-type relationship between environmental Na and Na uptake in juvenile D. magna, and found that the Na uptake assistance is saturable. Consequently, where environmental Na concentrations exceed the organism's uptake ability, only the true competitive binding effect is likely to exist, for which a smaller biotic ligand binding constant is likely to be representative.…”

“…This is plausible, because other studies have shown environmental sodium to assist sodium uptake in D. magna, and in juvenile D. magna in particular [37]. Consequently, the biotic ligand stability constant for sodium potentially incorporates the protective influence of competition for binding, alongside the uptake assistance provided by environmental sodium.…”

Genetic variation of Lymnaea stagnalis tolerance to copper: A test of selection hypotheses and its relevance for ecological risk assessment

“…Size-dependent sensitivity would result from the inhibiting effect of copper on sodium uptake, associated with a higher sodium turnover in smaller species (see Grosell et al, 2002). Within species, mechanisms of sodium uptake may differ between stages and lead to differential sensitivity to metals (e.g., Daphnia magna neonates vs adults; Bianchini and Wood, 2008). In the present case, as snails were conspecific and of the same stage, the explanation may be still different: larger size may simply reflects generally higher fitness, including for tolerance to metal stress.…”

Changes of the plankton community composition during chemical neutralisation of the Bockwitz pit lake

“…They are, for example, susceptible to changes of water chemistry as their iono-and osmoregulation (e.g. Na + , Ca 2 + ) critically depends on pH and on the presence of metal toxicants (Bianchini and Wood, 2008;Clifford and McGeer, 2009), which could be relevant in phases of soda application. In addition, high concentrations of abioseston as observed in the form of iron flocs (see above) are especially unfavourable for non-selective filter feeders such as daphnids (Kirk, 1991).…”