Do Quantity and Quality of Irradiance Influence Migration Behavior Motile Cells of the Green Alga, <i>Ulva fasciata</i>?

Abstract

Motile cells of the green alga, Ulva fasciata respond to the quantity and quality of irradiance simultaneously. The specific responses of motile cell types (gametes and spores) by irradiance influence migration behavior in coastal water environment. Gametes maximally aggregated at the highest white light intensity (250 μ mol &middot m -2 · s -1 ), while spores maximally aggregated in the dark (0 μ mol m -2 · s -1 ) of this study. Gametes maximally aggregated in green irradiance over blue, red and dark while spore maximally aggregated in the dark. The results of quantity are spectral responses are likely to be underline the ecological success and physiological strategies in varied irradiance environments includes: 1) gametes respond to specific quantities and spectral irradiance; 2) spores respond negatively to quantity and quality of irradiance to enhance the probability of finding substratum; and 3) populations of adults that come from these motile cells behaviors. The specific quantities and spectral qualities of irradiance responses show specific ecological migration that can be attributed to photosynthesis under limiting irradiance in coastal waters for the motile cells of U. fasciata .