R1 AM Nanotechnology Environmental and Health Impacts
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in Ballroom 1

(LOV-1117-732015) The Influence of Nanoparticles on Behavior: The Diminutive Diet of Daphnia.

Lovern, S¹, Klaper, R¹, Strickler, J¹, ¹ University of Wisconsin-Milwaukee Great Lakes WATER Institute, Milwaukee, WI, USA

ABSTRACT- As technology advances from using fine to nanoscale particles, the chemical and physical properties of these particles change as well as an increased surface area to volume ratio. With these changes, organisms can be greatly affected. This is especially true of aquatic organisms filtering their environment for food. In our previous work, we have found titanium dioxide (TiO₂) and fullerenes (C₆₀) to negatively influence survival of the Cladoceran Daphnia magna. In our current work, we are examining the behavior of Daphnia in response to nanoparticles. Other research with Daphnia has shown size and charge to be a factor in particle uptake; however, previous researchers did not examine particles at the nanoscale. During survival experiments at sublethal concentrations of nanoparticles, we found changes in behavior which are considered abnormal. Daphnia were often immobilized and appeared to be unable to swim down from the surface. The Daphnia would also swim in small circles or collide with vessel walls. In an effort to quantify these behavioral alterations, we have recorded Daphnia using a high-speed camera attached to a microscope mounted at 90°. A Picospritzer II (General Valve Corp) was used to expose tethered Daphnia to control as well as nanoparticle suspensions. Behavioral responses were recorded and specific behavior modifications will be shown in video clips. As changes in zooplankton behavior are known to affect predation risk, understanding the alternations caused by nanoparticles will help evaluate the sublethal effect of nanoparticles on the aquatic environment.

Key words: Nanoparticle, Daphnia behavior, fullerene, titanium dioxide