Effect of Varying Oxygen Concentrations on the Filtering Rate of Daphnia Pulex

Kring, R. Lynn; O’Brien, W. John

doi:10.2307/1936194

Cited by 68 publications

(33 citation statements)

References 27 publications

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“…However, it has been demonstrated that low oxygen reduces the filtration rate of zooplankton. Kring and O'Brien (1976) found that the filtration rate of the freshwater cladoceran, Daphnia pulex, decreased sharply when oxygen concentrations fell below 3 mg liter-I. This reduction in filtration activity may be a response to reduce metabolic rate in low-oxygen conditions.…”

Section: Resultsmentioning

confidence: 88%

Effects of low oxygen waters on Chesapeake Bay zooplankton

Roman

Gauzens

Rhinehart

et al. 1993

Limnology & Oceanography

190

112

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The bottom waters of the mesohaline portion of Chesapeake Bay become depleted in oxygen in summer. We found that copepods and nauplii were in low abundance or absent from bottom waters when oxygen concentrations were < 1 mg 0, litcr-I. In contrast, when oxygen concentrations were higher in bottom waters in spring or summer due to episodic mixing events, the highest copepod abundances were often found in bottom waters. Laboratory experiments confirmed that oxygen concentrations < 1 mg 0, liter-1 resulted in reduced survival of the copepods Acartia tonsa and Oithona colcarva and inhibited the hatching of A. tonsa eggs. The decrease in Chesapeake Bay copepods in May-June parallels the decline of oxygen in bottom waters. Our field and laboratory data suggest that this dcclinc in copepods could result from reduced recruitment as a consequence of egg mortality in the low-oxygen bottom waters. In summer this source of mortality would be reduced because warmer water temperatures would allow the eggs to hatch in the upper water column above the low-oxygen bottom waters.

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Section: Resultsmentioning

confidence: 88%

Effects of low oxygen waters on Chesapeake Bay zooplankton

Roman

Gauzens

Rhinehart

et al. 1993

Limnology & Oceanography

190

112

View full text Add to dashboard Cite

show abstract

“…This might explain why the critical ambient oxygen concentration of 3.9·mg·O2·l -1 (PO 2crit =7.9·kPa), which was predicted for the fasting state with doubled perfusion rate (Fig.·7A), was higher than the critical oxygen concentrations of 1.3-3.0·mg·O2 l -1 reported for filtering and respiration rates of Hb-poor D. magna and D. pulex (Kring and O'Brien, 1976; Oxyregulatory mechanisms in Daphnia magna Heisey and Porter, 1977;Kobayashi and Hoshi, 1984). The high sensitivity of the model to changes in the solubility coefficient for oxygen in the haemolymph (αH) indicates that Hb can have a pronounced effect on PO 2crit , since it enhances both the convective and diffusive transport of oxygen in the haemolymph.…”

Section: Discussionmentioning

confidence: 85%

The dichotomous oxyregulatory behaviour of the planktonic crustaceanDaphnia magna

Pirow

Buchen

2004

Journal of Experimental Biology

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SUMMARYThe dual function of appendage movement (food acquisition, ventilation)proved to be the key to explaining the peculiar oxyregulatory repertoire of the planktonic filter feeder Daphnia magna. Short-term hypoxic exposure experiments with normoxia-acclimated animals under varying food concentrations revealed a dichotomous response pattern with a compensatory tachycardia under food-free conditions and a ventilatory compensation prevailing under food-rich conditions. Food-free, normoxic conditions resulted in maximum appendage beating rates (fa) and half-maximum heart rates (fh), which restricted the scope for oxyregulation to the circulatory system. Food-rich conditions (105algal cells ml-1), on the contrary, had a depressing effect on fa whereas fh increased to 83% of the maximum. In this physiological state, D. magna was able to respond to progressive hypoxia with a compensatory increase in ventilation. A conceptual and mathematical model was developed to analyse the efficiency of ventilatory and circulatory adjustments in improving oxygen transport to tissue. Model predictions showed that an increase in perfusion rate was most effective under both food-free and food-rich conditions in reducing the critical ambient oxygen tension (PO2crit) at which oxygen supply to the tissue started to become impeded. By contrast, a hypothetical increase in ventilation rate had almost no effect on PO2crit under food-free conditions, indicating that appendage movement is driven by nutritive rather than respiratory requirements. However, the model predicted a moderate reduction of PO2crit by hyperventilation under food-rich conditions. Since the regulatory scope for an adjustment in fh was found to be limited in D. magna under these conditions, the increase in ventilation rate is the means of choice for a fed animal to cope with short-term, moderate reductions in ambient oxygen availability. Under long-term and more severe hypoxic conditions, however, the increase in the concentration and oxygen affinity of haemoglobin represents the one and only measure for improving the transport of oxygen from environment to cells.

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“…8). Daphnia in water with oxygen levels greater than 5 mg L Ϫ1 (i.e., the trout zone) were more vulnerable to predation, whereas those at depths with oxygen concentrations below 3 mg L Ϫ1 were presumably subject to elevated physiological stress (Kring and O'Brien 1976). Oxygen concentrations below 1 mg L Ϫ1 appeared to set the lower limit of the population's spatial distribution later in the year (Fig.…”

Section: Discussionmentioning

confidence: 98%

“…Depths with oxygen concentrations between 3 and 5 mg L Ϫ1 are defined as the ''refuge zone,'' because oxygen levels are lower than the threshold for trout but greater than the threshold concentration at which Daphnia become physiologically stressed. Kring and O'Brien (1976) showed that D. pulex (a closely related species) had significantly higher filtering rates and elevated hemoglobin production at oxygen concentrations below 3 mg L Ϫ1 . Depths with oxygen concentrations between 1 and 3 mg L Ϫ1 are defined as the ''hypoxic zone.''…”

Section: Methodsmentioning

confidence: 99%

Seasonal and diel patchiness of a Daphnia population: An acoustic analysis

Hembre

Megard

2003

Limnology & Oceanography

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Detailed information about the location and extent of zooplankton patches is fundamental to understand how abiotic and biotic forces interact to structure the spatial distribution of zooplankton. We mapped zooplankton patchiness in a Minnesota lake during spring, summer, and autumn with high-frequency (192-kHz) single-beam sonar. Conventional plankton samples of aggregations detected acoustically revealed that Daphnia pulicaria (mean body length 1.6 mm, mean target strength Ϫ120 dB) scattered most (ϳ63%) of the sound. Other taxa were smaller (Ͻ½ the length of D. pulicaria) and were usually less abundant and therefore scattered much less sound than D. pulicaria. Our acoustic estimates of Daphnia concentrations illustrate extreme patchiness, with concentrations varying by as much as four orders of magnitude over vertical distances of less than 1 m. Seasonal patterns of patchiness were related to predation by rainbow trout and to abiotic factors associated with stratification. Daphnia concentrations were highest from June to October in a deep-water ''refuge zone'' where oxygen concentrations were between 3 and 5 mg L Ϫ1 . These oxygen levels are suitable for Daphnia but are lower than those required by rainbow trout. Heterogeneity in Daphnia concentration along the lake's long axis was highest in May and June, when the population resided primarily in the oxic hypolimnion during the daytime. From July to October, as oxygen concentrations declined in the hypolimnion, the population became more metalimnetic and more uniformly distributed in the horizontal dimension. A diel study of the population in October indicated that the patchiness of population also changed dramatically between day and night. During the day the population aggregated densely in a thin layer (ϳ2 m thick) in the thermocline. After sunset the population dispersed into the epilimnion, where concentrations were ϳ100,000 m Ϫ3 less than they were during the day in the thermocline.Patchy spatial distributions and the low resolution of conventional sampling methods have impeded analyses of zooplankton populations. Zooplankton concentrations have been shown to vary by a factor of 1,000 within distances of meters horizontally or vertically, and the sampling resolution of conventional plankton nets and hoses is usually too coarse to identify the spatial limits of aggregations precisely (Coyle 2000). Variation in population density estimates due to sampling often cannot be distinguished from real changes of population density, and the effects of biological processes are difficult to distinguish from those of advective transport (Megard et al. 1997). Acoustic and optical plankton samplers developed during recent decades are major advances. They have very high sampling rates and spatial resolution, comparable to modern instruments (e.g., CTD profilers) used to measure environmental variables. Large numbers of plank-

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Effect of Varying Oxygen Concentrations on the Filtering Rate of Daphnia Pulex

Cited by 68 publications

References 27 publications

Effects of low oxygen waters on Chesapeake Bay zooplankton

Effects of low oxygen waters on Chesapeake Bay zooplankton

The dichotomous oxyregulatory behaviour of the planktonic crustaceanDaphnia magna

Seasonal and diel patchiness of a Daphnia population: An acoustic analysis

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