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- Moller, E. F., et al.
(author)
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Production of DOC by Calanus finmarchicus, C-glacialis and C-hyperboreus through sloppy feeding and leakage from fecal pellets
- 2003
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In: Marine Ecology-Progress Series. - 0171-8630. ; 262, s. 185-191
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Journal article (peer-reviewed)abstract
- Using C-14-labeled phytoplankton as tracer, we investigated 2 mechanisms of immediate dissolved organic carbon (DOC) release during grazing activity of Calanus spp. - sloppy feeding and leakage from newly expelled fecal pellets. Half of the carbon cleared by Calanus spp. was released as DOC through sloppy feeding. Freshly expelled fecal pellets lost more than 20% of their carbon content within the first hour, corresponding to 6% of the carbon cleared. Thus, copepods should not only be considered as an essential link to higher trophic levels, but also as a feedback link to the microbial food web.
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| 3. |
- Thor, Peter, 1965
(author)
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Elevated respiration rates of the neritic copepod Acartia tonsa during recovery from starvation
- 2003
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In: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 283:1-2, s. 133-143
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Journal article (peer-reviewed)abstract
- During prolonged periods of starvation, the respiration of copepods decreases to a basal metabolic rate. This is thought to enhance the survival probability by reducing the energy expenditure. The purpose of the present study was to investigate the recovery of the metabolism of Acartia tonsa from starvation. The respiration rate of nonstarved female A. tonsa was 0.95 +/- 0.17 nl O-2 individual(-1) min(-1) (mean S.E.). Starvation reduced the respiration rate to an average of 0.4 nl O-2 individual(-1) min(-1). Within a few hours after reintroduction to food, all starved individuals showed a hunger response in which their respiration rate not only increased to the respiration rate of those feeding constantly but also transiently rose above it. Thus, the maximal respiration rate of the starved individuals was 160% of the nonstarved rate. The duration of the hunger response depended on the duration of the preceding starvation period. The approximate amounts of oxygen respired in excess of the average nonstarved rate was 10 nl O-2 individual(-1) in copepods starved for 12 h, 60 nl O-2 individual(-1) in copepods starved for 24 h, and 150 nl O-2 individual(-1) in copepods starved for 36 h. The augmented respiration rates were probably induced to cover an increased energy demand for a "catch up" biosynthesis of gut cells and digestive enzymes during recovery. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 6. |
- Thor, Peter, 1965
(author)
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Specific dynamic action and carbon incorporation in Calanus finmarchicus copepodites and females
- 2002
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In: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 272:2, s. 159-169
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Journal article (peer-reviewed)abstract
- Specific dynamic action (SDA) and incorporation of carbon into protein, lipids, and polysaccharides were measured in copepodite CV and adult female Calanus finmarchicus during the spring/summer growth season in Raunefjorden, Norway. Organic carbon from the food (Rhodomonas baltica) was allocated differently in the two developmental stages. Copepodites incorporated 50-80% of the carbon into lipids and only 7-22% into protein. Carbon incorporation into protein was higher in females, constituting 23% in May at 7 degreesC and 34% in June at 11degreesC. This resulted in significant differences in the magnitude of SDA, measured as the increase in oxygen consumption during and after an 8-h feeding event. On average, the rate of carbon incorporation into protein was 2 times higher and the magnitude of SDA was 2.5 times higher in females than in copepodites. There was a significant correlation between the magnitude of SDA and carbon incorporation into protein suggesting that SDA is linked to protein synthesis. When comparing ATP equivalents of the magnitude of SDA with ATP equivalents of the total amount of carbon incorporated. more energy was produced than consumed. This supports speculations of an energy demand associated with a rapid turnover of newly synthesised protein. (C) 2002 Elsevier Science B.V All rights reserved.
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