Effects of light and column height on diel vertical migration of the marine gastropod Kelletia kelletii

Previous studies have shown that larval behavior, specifically diel vertical migration (DVM), can profoundly influence dispersal outcomes. Marine veliger Kelletia kelletii larvae exhibit DVM; larvae ascend at night and are demersal during the day (see Melissa Romero's research description by following the 'People' link). During summer 2007, as a new UMEB-SCERP scholar,  I worked with other scholars and Kim Walker in the Zacherl lab to investigate how light and vessel height influenced DVM behavior. We hypothesized that DVM behavior would be light- initiated and would not be affected by column height. We placed 100 larvae in replicate cultures (n = 4) under two different light treatments, natural (16:8) and a dark-only photoperiod (0:24), and two different column heights (15 or 125 cm).  Vertical positions in the column were recorded every 4 h for 24 h.  Column height and the interaction between photoperiod and time were significant (3-way full-factorial ANOVA for photoperiod, column height and time).  Cultures in shorter columns had significantly greater proportions of demersal larvae.  During daytime, natural photoperiod treatments had higher proportions of demersal larvae than dark-only treatments; at night there was no significant difference between light and dark treatments.

During summer 2008, I will pursue my own independent research. I would like to explore the relationship between coastal oceanographic features and larval distribution patterns of  Kelletia kelletii larvae or explore how variable food sources affect the pelagic larval duration of this species.