Sublethal impacts of nanomaterials may be  just as important or more important than their toxicity. Behavior plays a large role in reproduction, predation, and survival. We have found that certain nanomaterials have a greater influence on behavior of the critical freshwater invertebrate Daphnia. In addition the impact of the nanomaterial on behavior and physiology is influenced by the chemical structure and composition of the nanomaterial.

                                                                             Photo: Rebecca Klaper

Figure: Average change in behavior (events/minute with standard error) for each treatment group during the 60-min exposure. Time zero is the beginning of exposure immediately following the introduction of nanoparticles with a pipet. Time 60 is the end of the exposure period. Control  is the open triangle, TiO2 is the shaded triangle, nano-C60 is the open circle and, C60HxC70Hx is the shaded circle. ANOVA analysis showed hopping frequency was significantly altered in nano-C60 (P < 0.001) and
C60HxC70Hx (P < 0.001) suspensions. However, heart beat was only affected by nano-C60 and not the hydroxylated form. For other behaviors please refer to the publication listed below.

To see movies of Daphnia in action both before and after exposure to nanomaterials click the links below.  Note the amount of movement, specifically hopping behavior in the "After" movie.

Relevant Publications

Lovern, SB, JR Strickler, R. Klaper. 2007. Behavioral and physiological changes in Daphnia magna when exposed to nanoparticle suspensions (titanium dioxide, nano-C60, and C60HxC70Hx). Environmental Science and Technology 41(12):4465-70. [Link]