The goal of this project is to test the hypothesis that calcium ions within the cells of harmful algae trigger toxin release. (In animal cells, calcium ions cue the release of hormones.) Scientists will also attempt to show that harmful algae can sense environmental changes, process the information via cellular signaling and regulate cell physiology accordingly. The algae to be studied for the project include: the diatom Pseudo-nitzschia multiseries (which produces domoic acid); the dinoflagellate Karenia brevis (which produces brevetoxins) and Alexandrium fundyense (which produces saxitoxins). Findings have direct relevance to understanding harmful algal blooms at their most fundamental physiological level.