Swimming blind: A microscopic pursuit problem

indicators of water quality. In healthy systems, they are relatively sparse, but in algal blooms their density is found to be greater by two orders of magnitude [5]. Presently, there is very little understood about the connections between environmental parameters such as sunlight, nitrogen content, pH, the presence of prey, and dinoflagellate behavior. The purpose of this project is to try to understand one piece of the puzzle, dinoflagellate predatory behavior. Dinoflagellates are mixotrophs, meaning that they sustain themselves through photosynthesis and by grazing on prey organisms who are also mobile. The latter mode is more efficient. Predation is possible when a predator comes in physical contact with prey. The prey move similarly to predator. Dinoflagellates have no brain and no complex sensory organs, and are best considered simple machines. The flagella are driven by molecular motors that respond to chemical cues in the water, and it can be shown that simple motion like this can track up or down chemical gradients without being able to sense the gradient instantaneously [2]. Furthermore, it has been observed that the dinoflagellate Karodinium veneficum expresses a toxin when it comes in contact with prey. This karlotoxin is linked to two important processes. First, the toxin immobilizes the prey. Second, the toxin changes predator swimming behavior [5]. The key tasks are: