PH08 Metals in the Environment: Aquatic Biological Perspectives
Exhibit Hall
8:00 AM - Thursday
(PH098) Persistence of acclimation in larval and juvenile fathead minnows (Pimephales promelas) episodically exposed to copper.
Tate-Boldt, Erik1, Sellin, Marlo1, Kolok, Alan1, 1 University of Nebraska at Omaha, Omaha, Nebraska, USA
ABSTRACT- The objective of this study was to determine how long acclimation persists in larval and juvenile fathead minnows episodically exposed to Cu. In four different experiments, larvae (< 20d old) and juveniles (< 60d old) were allocated to one of four groups: unexposed, continuous, episodic or naïve. The continuous group was exposed to a sublethal Cu dose (125
g/L) immediately followed by a lethal Cu dose (375g/L). The episodic group was exposed to the sublethal dose, given a depuration period of varying lengths (4 to 16 d), then exposed to a lethal dose. Naïve minnows were maintained in clean water, then subjected to the lethal dose. In all experiments, survivability of the continuously exposed fish was significantly greater than that of the naïve fish, confirming that the fish had acclimated. Larval survivability of the episodically exposed fish given an 8-d depuration period was not significantly different from the survival of the continuously exposed fish, while the survival of the episodically exposed fish given a 12-d depuration was significantly reduced relative to continuously exposed fish. Juvenile survivability of the episodically exposed fish given an 8-d depuration was significantly lower than that of the continuously exposed fish. The results of this study indicate that the acclimatory response to Cu in fathead minnow larvae held in clean water persists for more than 8 d but fewer than 12 d. In contrast, juvenile fathead minnows are not capable of maintaining an acclimatory response following an 8 d depuration period. The increased persistence of acclimation in larvae relative to juveniles may be indicative of an increased phenotypic plasticity in the larvae that may be lost as the fish develop into juveniles.
Key words: acclimation, copper, episodic, ion regulation