Energy expenditure of swimming copepods
TL;DR: In this article, the deceleration patterns following a leap by the Calanoid copepod, Labidoceru trispinosn were used to determine the parameters k and n in the proposed drag law Co = k( Rc )-” where CD is the drag coefficient and Re is the Reynolds number.
Abstract: The deceleration patterns following a leap by the Calanoid copepod, Labidoceru trispinosn were used to determine the parameters k and n in the proposed drag law Co = k( Rc )-” where CD is the drag coefficient and Re is the Reynolds number. This relation was used to calculate the rate of energy expenditure in constant velocity swimming and in acceIerating from rest to a given velocity. At the velocities and accelerations observed, assuming 1000/o metabolic and propulsive efficiency, the rate of energy expenditure is slightly greater than 0.1% of the basal metabolic rate. It was also shown that at the swimming speeds observed during vertical migrations, the rate of energy expenditure is slightly less than 0.3% of the basal metabolic rate.
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TL;DR: Of the variables used (population densities, speeds of the two animal species, and encounter radius) the encounter radius has the greatest influence on the encounter probabilities.
Abstract: Predator–prey interactions between swimming animals of the zooplankton are studied in a mathematical model. The assumptions are: 1) the animals are points in a 1-m3 homogeneous space, 2) the animal...
829 citations
TL;DR: In this paper, the authors investigated the role of predation in the adaptive significance of vertical migration among zooplankton in both Gatun Lake in Panama and Fuller Pond in Connecticut.
Abstract: Field data and laboratory feeding experiments support the hypothesis that predation can be an important factor in the adaptive significance of vertical migration among zooplankton. In both Gatun Lake in Panama and Fuller Pond in Connecticut the diel vertical migration patterns of prey populations assume distributions which result in lessened predation by the dominant lake planktivores. It is concluded that such patterns of vertical migration will result when prey populations are under intense, selective pressures from visually dependent predators.
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Journal Article•
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TL;DR: Prediction of the population structure for both plants and herbivores may be a more attainable objective of theory and more practically important than prediction of total biomass at each trophic level.
Abstract: Interactions of herbivorous copepods with their phytoplankton food depend on the size composition of organisms in both trophic levels. A simulation model is used to analyse these size-dependent relations with the following conclusions. 1. Relative size structure of herbivores and their food is more important than total biomass of each trophic level in determining modes of transfer from plants to herbivores. In nearly all cases, in the model, food limitation affects reproduction or the first feeding stage of the nauplii. 2. No single factor emerges as predominant in determining the size structure of both populations. 3. The nature of predation on the herbivores is at least as important in determining both phytoplankton and herbivore size composition as physical or nutrient parameters. 4. The magnitude of the population of the larger herbivores such as Calanus, important as food for fish, depends on their coexistence with the smaller copepod species which control the smaller phytoplankton. 5. Stress on the system, if it affects adversely the smaller herbivores, can lead to the breakdown of the Calanus-diatom component. 6. Prediction of the population structure for both plants and herbivores may be a more attainable objective of theory and more practically important than prediction of total biomass at each trophic level.
224 citations
TL;DR: In this paper, the authors focus on respiration and feeding in copepods and discuss various factors influencing respiration, including crowding, time after capture, season, size, light, temperature, salinity, pressure, oxygen content of the water, and feeding.
Abstract: Publisher Summary This chapter focuses on respiration and feeding in copepods. Copepods are small, rarely exceeding 10 mm in length and form the bulk of most zooplankton hauls. They are found in both fresh and salt water, near the coasts and in the open ocean, and floating near the surface or crawling in the seashore sand. The chapter discusses various factors influencing respiration, including crowding, time after capture, season, size, light, temperature, salinity, pressure, oxygen content of the water, and feeding. Most pelagic copepods are neither purely herbivorous nor purely carnivorous but can change from one mode of feeding to the other. Thus, the mainly herbivorous, Calanus hyperboreus choose Artemia nauplii from a mixture of Artemia and smaller diatoms, and the mainly carnivorous, Anomalocera patersoni is occasionally found with a few diatom cells in the gut. The difference between carnivorous and herbivorous forms is not confined to their food but extends to the structure of their limbs, their larval development, and their oxygen consumption. Of the three main groups of copepods––namely, calanoida, cyclopoida, and parasitic, the chapter focuses only with the feeding mechanisms of calanoida and the cyclopoida.
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TL;DR: Seasonal variation in weight-corrected respiration and nitrogen excretion followed a similar pattern for all four species, being high in the spring and decreasing gradually through summer and fall to a winter minimum, however, the relative proportions of oxygen utilized to nitrogen excreted were different from season to season for each species.
Abstract: Rates of respiration and nitrogen excretion have been measured for freshly caught Calanus finmarchicus (Gunnerus), Calanus hyperboreus (Krayer), Metridia longa (Lubbock) and Pareuchaeta norvegica (Boeck), from the Gulf of Maine at all seasons. The dry weight, total (Kjeldahl) nitrogen, and fat were also determined for the same animals. Seasonal variation in weight-corrected respiration and nitrogen excretion followed a similar pattern for all four species, being high in the spring and decreasing gradually through summer and fall to a winter minimum. However, the relative proportions of oxygen utilized to nitrogen excreted were different from season to season for each species. In Calanus spp., O: N ratios by atoms were highest in May, immediately after the spring bloom of phytoplankton, when the animals were rich in fat. With C. hyperboreus the ratio then declined gradually through summer and fall to a low point just before the spring bloom (March and April) when populations contained the least amount of fat; but with C. finmarchicus the ratio fell much more rapidly, remaining near 17 through summer and fall and increasing again with the production of the overwintering generation. In Metridia and Pareuchaeta the O:N ratios did not show as much seasonal variation, although there was a pronounced increase for Metridia just after the spring bloom. Both species usually had higher respiration and excretion rates and lower O:N ratios compared with Calanus spp.
332 citations
TL;DR: In the euphausiid shrimp EUphausia pacifica, a member of the oceanic plankton, growth was as rapid as 0.048 mm/day in juveniles in the laboratory, more than twice as fast as that observed for oceanic populations by other workers.
Abstract: In the euphausiid shrimp Euphausia pacifica, a member of the oceanic plankton, growth was as rapid as 0048 mm/day in juveniles in the laboratory, more than twice as fast as that observed for ocean
267 citations
TL;DR: In this paper, the diurnal migration of Calanus was studied on two occasions in Loch Fyne (January and July, 1932) and the results for each copepodite stage were discussed, and January and July conditions are compared where possible.
Abstract: 1. Previous work on vertical distribution and diurnal migration is described.2. The diurnal migration of Calanus was studied on two occasions in Loch Fyne (January and July, 1932).3. Vertical hauls were taken every three hours with a closing net dividing the total depth into six sections.4. The results for each copepodite stage of Calanus are discussed, and January and July conditions are compared where possible.5. Ova and nauplii were observed to be most abundant in the top 30 metres.6. Copepodite Stages I, II, and III were most abundant above 30 metres and only the third copepodites showed any tendency to descend as the light increased.7. Stage IV showed a migration towards the surface at night, but were generally distributed during the next day.8. It is suggested that the results for this stage are probably confused owing to its transitional nature between the young stages living at the surface and Stage V Calanus living in deep water.9. Stage V was found always in deep water, slight diurnal changes being ascribed to the presence of such Calanus as were about to moult into adults.10. Females showed definite diurnal migration in both January and July.11. Males showed a general distribution and migrated in small numbers towards the surface at night and away from it during daylight.12. Stage V copepodites and females both lived nearer the surface in January than in July, correlated with seasonal changes in the intensity of the sunlight.13. The presence of swarms of Calanus at the surface under conditions of bright sunlight is discussed.
69 citations