Title of Presentation

Separating the effects of seawater viscosity and temperature on the feeding rates of the rotifer Brachionus plicatilis.

Type of Submission

Pre-recorded Poster

Research Field

Biology

Faculty Advisor

Dr.Will Jaeckle

Graduation Year

2022

Start Date

10-4-2021 8:00 AM

End Date

11-4-2021 5:00 PM

Abstract

Rates of swimming and feeding by small aquatic organisms are influenced by both the viscosity and temperature of water. Environmental temperature directly affects an organism’s metabolic rate and the water viscosity; an animal’s response to a change in temperature combines the separate influences of these two factors. Owing to their small size (< 1 mm), members of the phylum Rotifera are predicted to be strongly affected by water viscosity. We measured the separate effects of viscosity and temperature on feeding rates of the marine rotifer Brachionus plicatilis. Feeding by B. plicatilis was measured in three seawater treatments: (1) filtered seawater, (0.2 µm pore size, 15 ‰, 20 °C), (2) filtered seawater (15 ‰, 10 °C), and (3) filtered seawater (15 ‰, 20 °C, where the kinematic viscosity was adjusted to equal the viscosity of 10 °C seawater by the addition of the polysaccharide dextran). Rotifers in each treatment were incubated with 4.5 µm polystyrene beads (10,000 / mL) for 10 minutes, the number of beads ingested counted, and the clearance rate (volume of water "cleared" of particles / time) calculated. In each of three experiment replicates the clearance rates of B. plicatilis were significantly influenced by both temperature and viscosity (ANOVA, p < 0.001 for each). Rotifers in the 20 °C treatment (lowest viscosity) had the highest clearance rates, animals in the 10 °C treatment (highest viscosity) had the lowest clearance rates, and individuals in the 20 °C (10 °C viscosity) treatment revealed intermediate clearance rates. Within each experiment, the effect of each treatment level was significantly different (p < 0.05 for all comparisons). The overall influence of temperature on feeding by B. plicatilis was divided into a water viscosity effect 57.7%, and temperature effect 42.3%.

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Apr 10th, 8:00 AM Apr 11th, 5:00 PM

Separating the effects of seawater viscosity and temperature on the feeding rates of the rotifer Brachionus plicatilis.

Rates of swimming and feeding by small aquatic organisms are influenced by both the viscosity and temperature of water. Environmental temperature directly affects an organism’s metabolic rate and the water viscosity; an animal’s response to a change in temperature combines the separate influences of these two factors. Owing to their small size (< 1 mm), members of the phylum Rotifera are predicted to be strongly affected by water viscosity. We measured the separate effects of viscosity and temperature on feeding rates of the marine rotifer Brachionus plicatilis. Feeding by B. plicatilis was measured in three seawater treatments: (1) filtered seawater, (0.2 µm pore size, 15 ‰, 20 °C), (2) filtered seawater (15 ‰, 10 °C), and (3) filtered seawater (15 ‰, 20 °C, where the kinematic viscosity was adjusted to equal the viscosity of 10 °C seawater by the addition of the polysaccharide dextran). Rotifers in each treatment were incubated with 4.5 µm polystyrene beads (10,000 / mL) for 10 minutes, the number of beads ingested counted, and the clearance rate (volume of water "cleared" of particles / time) calculated. In each of three experiment replicates the clearance rates of B. plicatilis were significantly influenced by both temperature and viscosity (ANOVA, p < 0.001 for each). Rotifers in the 20 °C treatment (lowest viscosity) had the highest clearance rates, animals in the 10 °C treatment (highest viscosity) had the lowest clearance rates, and individuals in the 20 °C (10 °C viscosity) treatment revealed intermediate clearance rates. Within each experiment, the effect of each treatment level was significantly different (p < 0.05 for all comparisons). The overall influence of temperature on feeding by B. plicatilis was divided into a water viscosity effect 57.7%, and temperature effect 42.3%.