The costs of moulting in <i>Daphnia;</i> mineral regulation of carbon budgets

Hessen, Dag O.; Rukke, Nina Alstad

doi:10.1046/j.1365-2427.2000.00670.x

Cited by 63 publications

(55 citation statements)

References 47 publications

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“…Similarly, a higher proportion of Ca was lost through molting in Daphnia magna (Tan & Wang 2009). These results indicate that Ca and P were linked in the building and shedding of molts (Hessen & Rukke 2000). Similar numbers of molts were generated by daphnids at different Ca levels, suggesting that the molting frequencies were generally unaffected by the ambient Ca level, which is in agreement with .…”

supporting

confidence: 82%

“…shed and re-build their exoskeleton periodically as they grow, leading to a substantial drain of, and demand for, a number of elements. Calcium and phosphorus have attracted much attention (Peters & Rigler 1973, Alstad et al 1999, Hessen & Rukke 2000, He & Wang 2007 due to their high content in the exoskeleton and high requirement by Daphnia. Most Ca in Daphnia is bound within the carapace and ~90% of Ca in Daphnia magna is lost during 1 molting event (Alstad et al 1999).…”

Section: Introductionmentioning

confidence: 99%

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Calcium influence on phosphorus regulation in Daphnia magna: implications for phosphorus cycling

Tan¹,

Wang

2009

Aquat. Biol.

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We examined the influence of environmental calcium on phosphorus biokinetics and regulation in Daphnia magna. When the Ca concentration in culturing media increased from 0.5 to 200 mg l -1 , the specific P content of D. magna feeding on P-sufficient algae decreased significantly from 1.43 to 1.05% of dry weight. There was a significant negative relationship between the specific Ca and P contents (% dry wt) of daphnids. However, measured biokinetic parameters, including the assimilation efficiency (AE) of dietary P, the weight-specific ingestion rate (IR), the uptake of inorganic P from water, and the efflux rate constant (k e ) of P, were similar over the wide range of Ca concentrations, with some exceptions at the lowest Ca level (0.5 mg l -1 ). Diet was the dominant source of P for daphnids, and only 1 to 2% of P was incorporated from water, based on the biokinetic calculation. With the elevation of the Ca level from 0.5 to 200 mg l -1 , the proportion of P lost through molting by D. magna feeding on P-sufficient diets increased 2.5-fold, whereas the dissolved release decreased 1.9-fold. P released into the dissolved phase is readily re-utilized by primary producers, while P contained within the shed molts sinks out of the epilimnion and becomes at least temporarily unavailable to primary producers; thus, the effects of Ca on molting and dissolved release have significant implications for P cycling in freshwater lakes. Our results suggest that the availability of P to primary producers can be reduced by sedimentation of P-rich daphnid molts in high-Ca lakes, and Ca concentration in the water needs to be considered in studying the stoichiometric regulation of P in freshwater cladocerans. KEY WORDS: Phosphorus regulation · Phosphorus cycling · Phosphorus biokinetics · Effects of calcium · Daphnia magna Resale or republication not permitted without written consent of the publisherThe relative importance of different routes of phosphorus loss from Daphnia magna (via excretion, reproduction and molting) is affected by the calcium level in the water. Photo: Ke Pan OPEN PEN ACCESS CCESSAquat Biol 5: [1][2][3][4][5][6][7][8][9][10][11] 2009 of P is distributed within the carapace, possibly bound with Ca. Sterner et al. (1993) found that D. obtusa on a P-deficient diet has problems in molting. Shedding molts accounts for ~70 and ~50% of P loss from juvenile and adult D. magna over a 3 to 4 d period, respectively (He & Wang 2007). The link between Ca and P in D. magna is also indicated by the crystalline calcium phosphate composition of the shell of its ephippia (Kawasaki et al. 2004). Ca levels in the water considerably affect the calcification of the carapace of daphnids (Alstad et al. 1999) and, thus, their total Ca content (Jeziorski & Yan 2006, Tan & Wang 2008. It is therefore tempting to ask whether the content and distribution of P in daphnids is also affected by the aqueous Ca level, considering the close association of these 2 elements in these organisms. Among the various freshwater zooplankton s...

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supporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Calcium influence on phosphorus regulation in Daphnia magna: implications for phosphorus cycling

Tan¹,

Wang

2009

Aquat. Biol.

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“…In addition, under certain conditions, such as rapid asynchronous moults, the relative durations of the moult stages represent pro- portions of individuals in a population. This is the case, for example, for small crustacean species such as cladocerans (Bottrell 1975, Hessen & Alstad Rukke 2000, copepods in breeding, or for tropical shrimps or northern shrimps during summer (Benayoun & Fowler 1980). Because information on moult stage duration in hydrothermal species is lacking, results can only be compared with data on a few shallow-water shrimps.…”

Section: Moult Cycle In Life Environmentmentioning

confidence: 99%

Bacterial symbionts and mineral deposits in the branchial chamber of the hydrothermal vent shrimp Rimicaris exoculata: relationship to moult cycle

Corbari¹,

Zbinden²,

Cambon-Bonavita³

et al. 2008

Aquat. Biol.

104

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The shrimp Rimicaris exoculata is considered a primary consumer that dominates the fauna of most Mid-Atlantic Ridge hydrothermal ecosystems. The shrimps harbour in their gill chamber an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The settlement and development of this ectosymbiosis was investigated using microscopy techniques (light microscopy, LM; and scanning, transmission and environmental scanning electron microscopy: SEM and ESEM, respectively) for shrimps from 2 different vent fields (Rainbow, 36°14.0' N and TAG, 26°08.0' N). The results revealed a bacterial re-colonisation after each exuviation and a development of the bacterial community in 5 steps in relation to the moult stages, which were used as a reference time scale. In 287 shrimps from both vent fields, pre-ecdysial stages prevailed in the population, suggesting a short anecdysis and high moulting rate, probably to renew the ectosymbiosis. Comparisons with moult cycles of littoral shrimps suggest that the interval between successive exuviations in R. exoculata may be as short as 10 d. The colours of R. exoculata result from accumulation of iron oxide, which forms a bacteria-associated mineral crust in the gill chambers. The close correspondence between moult stages, the development of the ectosymbiont community and shrimp colours indicate that colour could be used to rapidly determine shrimp moult stages.

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“…The amount of cholesterol in D. magna was related to the carbon content of somatic tissues and eggs instead of dry mass to diminish the effect of the carapace, which likely has a low cholesterol content and a relatively high mineral content (Hessen and Rukke, 2000). The mean carbon content (± s.d.)…”

Section: Chemical Analysismentioning

confidence: 99%

“…Interestingly, at a given dietary cholesterol level, the cholesterol content in eggs was higher than in somatic tissues, a pattern that has also been observed for a marine copepod species (Hassett and Crockett, 2009). However, adult animals allocate a certain proportion of their mass to the chitinous carapace, which has a relatively high mineral content (Hessen and Rukke, 2000) and probably a low cholesterol content since cholesterol is primarily localized in plasma membranes. The carapace can therefore add a low cholesterol fraction to the mass of the somatic tissue, compared with eggs, and thus the cholesterol content of the membranes could actually remain constant while the massspecific cholesterol content differs between somatic tissues and eggs.…”

Section: Allocation Of Cholesterol Into Somatic Tissues or Eggsmentioning

confidence: 99%

Effects of temperature and dietary sterol availability on growth and cholesterol allocation of the aquatic keystone speciesDaphnia

Sperfeld

Wacker

2009

Journal of Experimental Biology

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SUMMARYEnhanced water temperatures promote the occurrence of cyanobacterial blooms, which may be detrimental to aquatic herbivores. Especially, the often-dominant crustaceans could be negatively affected because cyanobacteria are deficient in phytosterols, which are required by the crustaceans to form the membrane component cholesterol, which in turn plays a role in thermal adaptation. Here, we determined the influence of temperature on growth, reproduction and the allocation of dietary sterol into somatic tissues and eggs of the keystone species Daphnia magna raised along a dietary cholesterol gradient. Mass-specific growth rates of D. magna increased with the increasing availability of dietary cholesterol up to an incipient limiting level, which increased with increasing temperature. This indicates a higher demand for cholesterol for growth at higher temperatures and may explain the consistently smaller clutch sizes of reproducing females at the highest temperature. The cholesterol content of the individuals increased with increasing dietary cholesterol; this increase was enhanced at higher temperatures, indicating a higher demand for cholesterol for tissues and probably specifically for membranes. Surprisingly, the daphnids showed different allocation strategies with regard to temperature and dietary sterol availability. The cholesterol content of eggs was enhanced at higher temperature, which suggested that females allocate more cholesterol to their offspring, presumably to ensure sufficient egg development. When dietary cholesterol was limiting, however, females did not allocate more cholesterol to their eggs. Our data suggest that during cyanobacterial blooms, a potential dietary sterol limitation of Daphnia can be intensified at higher water temperatures, which can occur with global warming.

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The costs of moulting in Daphnia; mineral regulation of carbon budgets

Cited by 63 publications

References 47 publications

Calcium influence on phosphorus regulation in Daphnia magna: implications for phosphorus cycling

Calcium influence on phosphorus regulation in Daphnia magna: implications for phosphorus cycling

Bacterial symbionts and mineral deposits in the branchial chamber of the hydrothermal vent shrimp Rimicaris exoculata: relationship to moult cycle

Effects of temperature and dietary sterol availability on growth and cholesterol allocation of the aquatic keystone speciesDaphnia

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