Seasonal Calorific Values of Freshwater Zooplankton, as Determined with a Phillipson Bomb Calorimeter Modified for Small Samples

Schindler, D. W.; Clark, Abigail S.; Gray, JS

doi:10.1139/f71-079

Cited by 51 publications

(20 citation statements)

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“…The choice of this temperature was determined by the need to remove water and the demonstration that it is a safe temperature to use in relation to lipids (Schindler et al 1971).…”

Section: Methodsmentioning

confidence: 99%

“…Achieving constant dry weight at 50°C does not mean that all the water has been driven off. A later study compared freeze drying with oven drying at up to 100°C and showed no significant difference in the weights obtained by the 2 methods (Schindler et al 1971). Compared with lipids of general plankton, salp lipids are less likely to be affected by high temperature as microscopic examination shows no evidence of volatile lipid storage globules common at times in Crustacea.…”

Section: Weight Determinationmentioning

confidence: 98%

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Length-weight relation in the salp Thalia democratica and potential of salps as a source of food

Heron¹,

McWilliam²,

Pont³

1988

Mar. Ecol. Prog. Ser.

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Improved methods of analyzing length-weight relations in the fast-growing salp Thaha dernocratica enable future calculation of productivity from population data and show that carbon density in relation to wet weight for sizes of salps commonly available as food is similar to that of Crustacea. A power relation was developed: Carbon Weight (@gC) = 1.62 X Length (r2 = 0.87, n = 39). Measurements were taken over a wider range of sizes than before (including 0.4 mm embryos). No significant difference between solitary and aggregate stages could be detected. Dry weight was 8.04 % of wet weight (SE = 1.01), ash-free dry weight was 46.5 O/o of dry weight (SE = 1.1), and carbon weight was 38.7 % of ash-free dry weight (SE = 2.8). Carbon was found to be a better reference measurement than either wet or dry weight. The C: N ratio was 3.81 : 1 (SE = 0.06). Tissue shrinkage after preservation was significantly different in buffered formalin than in Steedman's solution. Formulae are given for calculating live length from preserved length up to 2 yr after preservation. Previous estimates of wet weight, dry weight and ash in salps were improved by removlng internal seawater and salt and driving off most of the 'bound' water; these improvements are also applicable to other gelatinous organisms. Salp weight increases as length squared rather than cubed, because tissue density declines with growth between 3 and 10 mm. Salp tissue density is much closer to that of other marine invertebrates, such as molluscs and crustaceans, than was previously reported in the literature. Contrary to expectations, the ratio of dry and ash-free dry weight to wet weight is high during the most rapid growth period, from 2 to 7 mm. Whlle the average density of T. democratica in relahon to wet weight is now seen to be comparable to that of molluscs and chaetognaths (not, as previously thought, to that of medusae and siphonophores), the density of 4 mm individuals reaches that of the arthropods. Coupled with high growth rates, this result makes the salp likely to be a much more important source of food for fish than was previously realized.

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“…The choice of this temperature was determined by the need to remove water and the demonstration that it is a safe temperature to use in relation to lipids (Schindler et al 1971).…”

Section: Methodsmentioning

confidence: 99%

Section: Weight Determinationmentioning

confidence: 98%

Length-weight relation in the salp Thalia democratica and potential of salps as a source of food

Heron¹,

McWilliam²,

Pont³

1988

Mar. Ecol. Prog. Ser.

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“…Koi:inek,personal communication After sorting, the Daphnia were ovendried to constant weight at 105C and stored in a desiccator until combustion in a GentryWeigert modification of the Phillipson ( 1964) oxygen microbomb calorimeter. The temperature rise was measured with thermocouples and recorded, The use of standard thermocouples may result in large variances with small samples ( Schindler et al 1971) and an attempt was made to use samples in excess of 12 mg whenever possible. The bomb was calibrated with thermochemical standard benzoic acid (6,318 Cal/g, B.D.H. )…”

Section: Materials Asd Methodsmentioning

confidence: 99%

“…Such data for freshwater zooplankton are relatively few (c .g. Richman 1958;Schindler et al 1971;1Vissing andHasler 1968, 1971). Studies of seasonal variation in the energy content of zooplankton (freshwater or marine) are even more scarce.…”

Section: Studies Of Energy Relationshipsmentioning

confidence: 99%

“…Comita et al ( 1966) determined seasonal fluctuations in the calorific value of the marine copepod Calanus f inmard icus. Schindler et al (1971) investigated seasonal changes in the calorific value of some freshwater zooplankters and U'issing and Hasler ( 1968,1971) carried out a similar study, although 011 water zooplanktonic and benthic in\rertc-brates.…”

Section: Studies Of Energy Relationshipsmentioning

confidence: 99%

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THE EFFECT OF SEASON AND ANIMAL SIZE ON THE CALORIC CONTENT OF DAPHNIA PULICARIA FORBES1,2

Snow

1972

Limnology & Oceanography

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The population of Daphnia pdicaria Forbes in West Blue Lake, IrIanitoba, was sampled monthly for over a year. Very small animals were entirely absent during winter when no reproduction was occurring, while large, red, fat-laden individuals were more numerous than at any other time. In spring, large numbers of small animals appeared and the largest size classes virtually disappeared, to reappear the following winter.The large, fat, winter animals had a very high energy content ( -9,000 Cal/g dry wt ) whereas smaller individuals at the same time had values similar to those later in summer. Caloric content of all sizes decreased as summer progressed (-4,900 Cal/g dry wt) and the inequality between different sizes also disappeared. During November the mean caloric content began to rise again ant I once more large animals had higher values than smaller ones.

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Some Factors Affecting on Dry Weight, Organic Weight and Concentrations of Carbon and Nitrogen in Freshly Prepared and in Preserved Zooplankton

Ōmori

1978

Intl Review of Hydrobiology

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Effects of rinsing and preservation on dry weight, organic weight, and chemical composition were determined on the chaetognath Sagitta nagae and the copepods Calanus sinicua, Pleuromamrna xiphias and Acartia tonsa. Samples rinsed with distilled water were always lighter than comparable samples rinsed with seawater, showing apparent decrease in the organic matter and chemical contents (as total carbon and nitrogen) by weight ; these losses increased with increasing volume of the rinse water. The volume of distilled water used for rinsing should be less than 0.3 ml per 1 mg dry weight of sample in order to avoid the significant loss of body substances. Isotonic ammonium formate rinse often resulted in the widest range of variation and on an average the organic weight and chemical contents were slightly lower than those of fresh samples rinsed with filtered seawater. Freeze-drying samples resulted in dry and organic weights as well as chemical compositions that were somewhat greater than oven-dried samples. The organic matter and chemical contents by weight decreased significantly within 2.5 days of being placed in Borax-buffered formaldehyde-seawater solution. Loss of organic weight from fresh samples exceeded 20% after one week of the preservation. Hexamine-buffered formaldehyde solution showed a result which was different from the Borax-buffered solution.

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Seasonal Calorific Values of Freshwater Zooplankton, as Determined with a Phillipson Bomb Calorimeter Modified for Small Samples

Cited by 51 publications

References 0 publications

Length-weight relation in the salp Thalia democratica and potential of salps as a source of food

Length-weight relation in the salp Thalia democratica and potential of salps as a source of food

THE EFFECT OF SEASON AND ANIMAL SIZE ON THE CALORIC CONTENT OF DAPHNIA PULICARIA FORBES1,2

Some Factors Affecting on Dry Weight, Organic Weight and Concentrations of Carbon and Nitrogen in Freshly Prepared and in Preserved Zooplankton

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