Browsing and grazing by cladoceran filter feeders

1979 ◽  
Vol 57 (1) ◽  
pp. 206-212 ◽  
Author(s):  
P. A. Horton ◽  
M. Rowan ◽  
K. E. Webster ◽  
R. H. Peters
Keyword(s):  
Ingestion Rate ◽  
Daphnia Pulex ◽  
Food Concentration ◽  
Suspension Feeding ◽  
Culture Vessel ◽  
Planktonic Food ◽  
Laboratory Cultures ◽  
Food Concentrations ◽  
Ceriodaphnia Quadrangula ◽  
Minimum Requirements

If different Cladocera have similar minimum requirements for suspended food, the capacity to utilize sedimented material would shift the competitive advantage to facultative bottom foragers in ponds, shallow lakes, and laboratory cultures with fluctuating levels of planktonic food. In laboratory cultures, Daphnia pulex browses or forages on the bottom of its culture vessel when suspended food concentration is too low to support reproduction or high rates or ingestion. Suspension feeding or grazing is the primary feeding mechanism only above the incipient limiting food concentration when ingestion rate is maximal, although a proportion of the animal's time is spent swimming (and therefore suspension feeding) at all food concentrations. Limited evidence suggests that different species of Cladocera have similar food levels at which reproduction is zero, yet not all are facultative browsers. Daphnia magna exhibits a similar behaviour to D. pulex but D. galeata and Ceriodaphnia quadrangula do not. These results show that the switch from grazing to browsing may be a determinant of competitive success among Cladocera.

scholarly journals Inducible morphological defense in Daphnia pulex: food quantity effects revised

2020 ◽  
Author(s):  
Sandra Klintworth ◽  
Eric von Elert
Keyword(s):  
Chemical Cues ◽  
Daphnia Pulex ◽  
Food Concentration ◽  
Bacterial Degradation ◽  
Inducible Defenses ◽  
Chemical Cue ◽  
High Food ◽  
Food Quantity ◽  
Morphological Defense ◽  
Food Concentrations

Abstract In aquatic systems, organisms largely rely on chemical cues to perceive information about the presence of predators or prey. Daphnia recognize the presence of the predatory larvae of Chaoborus via a chemical cue, emitted by the larvae, a so-called kairomone. Upon recognition, neckteeth, an alteration of the carapace, are induced in Daphnia that reduce predation rates of Chaoborus. Neckteeth induction was often reported to entail costs. In a previous study, food quantity affected the level of neckteeth induction, with stronger neckteeth induction at low food concentrations and weak induction at high food concentrations. However, reducing neckteeth induction at high food quantities seems to be maladaptive and not in accordance with the concept that inducible defenses are associated with costs. Here, we hypothesized that weaker neckteeth induction at high food concentrations is caused by increased bacterial degradation of the kairomone. More specifically, we assume that higher algal food concentration is associated with higher bacterial abundances, which degrade the kairomone during the experiment. We tested our hypothesis by treating food algae with antibiotics before providing them as food to Daphnia. Antibiotics reduced bacterial abundances at high and low food concentrations. Reduced bacterial abundances at high food concentrations led to the same level of neckteeth induction as at low food concentrations. A linear regression revealed a significant correlation of neckteeth induction to bacterial abundances. We therefore conclude that differences in neckteeth induction at different food concentrations are not caused by the food quantity effects but by differences in bacterial degradation of the kairomone.

Functional response to Daphnia carinata King when feeding on the filamentous diatom Melosira granulata

1993 ◽  
Vol 44 (5) ◽  
pp. 761 ◽  
Author(s):  
CR King ◽  
RJ Shiel
Keyword(s):  
Functional Response ◽  
Food Item ◽  
Ingestion Rate ◽  
Dry Weight ◽  
Food Concentration ◽  
Daphnia Carinata ◽  
Food Concentrations

The functional response of D. carinata feeding on M. granulata was determined from laboratory trials conducted at 20-22�C, using a range of food concentrations (F) from 0.14 to 33.8�g (dry weight) mL-1. The functional response could be described by an lvlev model: I (ingestion rate, ng �g-1 h-1) = 200 - 205 × exp (- 0.036 × F). The ingestion rate at the highest food concentration (33.8 �g mL-1) was 140 ng �g-1 h-1, and there was no evidence to suggest that M. granulata either interfered with feeding at high densities or was a difficult food item for D. carinata to handle.

The Effect of Temperature and Food Concentration On Ingestion Rates of Quinqueloculina Seminula On the Diatom Nitzschia Closterium

2019 ◽  
Vol 49 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Yanli Lei ◽  
Chengchun Li ◽  
Tiegang Li ◽  
Zhimin Jian
Keyword(s):  
Food Availability ◽  
Ingestion Rate ◽  
Food Concentration ◽  
Laboratory Culture ◽  
Effect Of Temperature ◽  
Clearance Rates ◽  
Organic Detritus ◽  
Local Conditions ◽  
Ingestion Rates ◽  
Nitzschia Closterium

Abstract The majority of sediment-dwelling foraminifera are thought to be deposit feeders. They use their reticulopodia to gather sediment with associated algae, organic detritus, and bacteria. Uptake of diatoms by foraminifera have been observed but rarely quantified. We measured the clearance (gathering) rate and ingestion rate of diatoms by the common benthic foraminifer Quinqueloculina seminula using Nitzschia closterium as prey under laboratory culture conditions. Grazing experiments were performed to evaluate the effects of temperature (at 12, 15, 18, 21, and 24°C) and food availability (10 to 800 cells mm−2) on uptake rates of diatoms. The clearance rates, estimated from the disappearance of food items, were variable (0.59–4.4 mm2 foram−1 h−1) and did not show a clear relationship with food availability. The maximum clearance rates increased from 1.80 ± 0.21 to 2.69 ± 0.32 mm2 foram−1 h−1 when temperature increased from 12 to 18°C and decreased to 2.28 ± 0.25 mm2 foram−1 h−1 at 24°C. Ingestion rates varied from 1.0 to 43 × 103 diatoms foram−1 h−1, following a hyperbolic response to food concentrations at all experimental temperatures. The maximum individual ingestion rates increased from 842 ± 180 to 1648 ± 480 (mean ± SE) cells foram−1 h−1 and then decreased to 316 ± 54 cells foram−1 h−1 as temperature increased from 12 to 24°C. Experimental results revealed that 12–18°C was the optimal temperature range for Q. seminula feeding for specimens adapted to local conditions. Our study indicates that Q. seminula plays an ecological role by feeding upon benthic diatoms in marine benthic ecosystems.

scholarly journals Interactions Between the Kleptoplastidic Dinoflagellate Shimiella gracilenta and Several Common Heterotrophic Protists

2021 ◽  
Vol 8 ◽  
Author(s):  
Sang Ah Park ◽  
Hae Jin Jeong ◽  
Jin Hee Ok ◽  
Hee Chang Kang ◽  
Ji Hyun You ◽  
...  
Keyword(s):  
Growth Rates ◽  
Ingestion Rate ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Prey Concentration ◽  
Ingestion Rates ◽  
Oxyrrhis Marina ◽  
Planktonic Food ◽  
Moderate Growth ◽  
Algal Prey

The newly described dinoflagellate, Shimiella gracilenta, is known to survive for approximately 1 month on the plastids of ingested prey cells during starvation, indicating kleptoplastidy. To understand the population dynamics of this dinoflagellate in marine planktonic food webs, its growth and mortality rate due to predation should be assessed. Thus, we investigated the feeding occurrence of eight common heterotrophic protists on S. gracilenta. We also determined the growth and ingestion rates of Oxyrrhis marina and the naked ciliate, Rimostrombidium sp. on S. gracilenta as a function of the prey concentration. The common heterotrophic dinoflagellates (HTDs) Gyrodinium dominans, O. marina, and Pfiesteria piscicida and a naked ciliate Rimostrombidium sp. were able to feed on S. gracilenta; whereas the HTDs Aduncodinium glandula, Gyrodinium jinhaense, Oblea rotunda, and Polykrikos kofoidii were not. Shimiella gracilenta supported positive growth of O. marina and Rimostrombidium sp. but did not support that of G. dominans and P. piscicida. With increasing prey concentrations, the growth and ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta increased and became saturated. The maximum growth rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.645 and 0.903 day−1, respectively. Furthermore, the maximum ingestion rates of O. marina and Rimostrombidium sp. on S. gracilenta were 0.11 ng C predator day−1 (1.6 cells predator−1 day−1) and 35 ng C predator day−1 (500 cells predator−1 day−1), respectively. The maximum ingestion rate of O. marina on S. gracilenta was lower than that on any other algal prey reported to date, although its maximum growth rate was moderate. In conclusion, S. gracilenta had only a few common heterotrophic protist predators but could support moderate growth rates of the predators. Thus, S. gracilenta may not be a common prey species for diverse heterotrophic protists but may be a suitable prey for a few heterotrophic protists.

Molt-Related Sensitivity of Daphnia pulex in Toxicity Testing

1979 ◽  
Vol 36 (9) ◽  
pp. 1129-1133 ◽  
Author(s):  
David Robert Lee ◽  
Arthur L. Buikema Jr.
Keyword(s):  
Daphnia Pulex ◽  
Toxicity Testing ◽  
Continuous Exposure ◽  
Clean Water ◽  
Survival Times ◽  
Short Term ◽  
Chromium Toxicity ◽  
Short Term Exposure ◽  
Laboratory Cultures ◽  
Cyclic Changes

Continuous and short-term exposures of Daphnia pulex to 0.56 mg Cr/L showed that these animals undergo cyclic changes in susceptibility. Short-term exposure (2 h) followed by transfer to clean water for 22 h resulted in significantly higher mortality for individuals that molted during exposure. Continuous exposure to chromate resulted in significantly shorter mean survival times for animals that had molted < 4 h before being placed in chromate solution. Because laboratory cultures can be synchronized with respect to molting, the effects of cyclic sensitivity can bias bioassay results. By examining the animals at the beginning of the test, the degree of synchrony can be determined and appropriate steps taken. Key words: bioassay, Daphnia pulex, chromium toxicity, molting

scholarly journals A modelling study of the influence of environment and food supply on survival of Crassostrea gigas larvae

2004 ◽  
Vol 61 (4) ◽  
pp. 596-616 ◽  
Author(s):  
Eileen E Hofmann ◽  
Eric N Powell ◽  
Eleanor A Bochenek ◽  
John M Klinck
Keyword(s):  
Genetic Variation ◽  
Food Quality ◽  
Egg Quality ◽  
Larval Growth ◽  
High Growth ◽  
Growth Efficiency ◽  
Food Concentration ◽  
Larval Survival ◽  
Food Concentrations ◽  
Food Content

Abstract A biochemically based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster (Crassostrea gigas). The unique characteristics of the model are that it: (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate, and ash content; (2) tracks weight separately from length to follow larval condition; and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for filtration, ingestion, and respiration, which determine larval growth rate, and processes controlling larval mortality and metamorphosis. Changes in larval tissue composition occur as the larva grows and in response to the biochemical composition of the food. Simulations of larval growth indicate that departures of temperature, salinity, or food content from optimum levels reduce larval cohort survival, either because of metabolic constraints that result in death, unsuccessful metamorphosis, or increased predation resulting from increased larval lifespan. Temperatures and salinities near optimal values improve larval survival at low food concentration by increasing ingestion rate or growth efficiency. Also, survival at a given food concentration can vary widely depending on food composition, which determines food quality. The simulations suggest that the ratio of carbohydrate + lipid-to-protein may best describe the overall food quality, with optimal food compositions being characterized by ratios near 1.2 to 1.4 over a range of food concentrations. In contrast, food compositions containing too much or too little protein reduce larval survival, even at saturating food concentrations. In simulations emphasizing genetic variability within the cohort, larvae with high growth efficiency originating from large eggs out-perform other egg quality–growth efficiency combinations over a wide range of temperature, salinity, and food contents. As a consequence, suboptimal temperature, salinity, or food content compresses genetic variation by uniformly favouring larvae from large eggs with a high growth efficiency. However, the larval survival obtained from simulations that use a range of food qualities is representative of a much broader range of genetic types. Thus, the simulations support the supposition that food quality is an important variable controlling the survival and genetic variability of C. gigas larval cohorts.

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