(full paper is archived in the Miller Library)
Title: Negative effects of the herbicide atrazine on planula
settlement in the scyphozoan medusa Aurelia labiata
Student Author(s): Nava, Raul
Faculty Advisor(s): Epel, David
Location: Final Papers Biology 175H
Date: June 2004
Abstract: Anthropogenic pollution has widespread impacts on development of marine organisms as myriad chemicals make their way into coastal ecosystems. The present study examined effects of the commonly used herbicide atrazine. Potential effects of atrazine were observed using scyphozoans, model organisms useful as indicators of unbalanced ecosystems, specifically testing effects on cultured planula larvae of the medusa Aurelia labiata. Planula settlement was observed over 14 days in seawater with 3 dilutions of atrazine (l ppb, 10 ppb, and 30 ppb). Turnover time, when population dominance shifted from free-swimming larvae to sessile polyps, was longest in the highest atrazine dilution relative to the control treatment (6.27 days versus 1.96 days, respectively), indicating a significant treatment effect of atrazine (P=0.0015). Similarly, cumulative mortality was higher with increased atrazine concentration. These data suggest atrazine negatively effects development of cnidarians. Scyphozoans are typically more tolerant of poor ocean conditions, therefore these results raise concern for effects on other marine organisms more sensitive to environmental conditions.