does motility promote dinoflagellate persistence or co-existence with diatoms?
N Broekhuzien National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, Hamilton, New Zealand Dinoflagellates are characterized by low maximum photosynthetic rates and high respiratory costs. Recent evidence also suggests that dinoflagellates are disproportionately abundant in the diets of many copepods. This suggests that at least some species are preferred prey types. This begs the question: ‘How do dinoflagellates co-exist with other, seemingly competitively superior, algal taxa’? Their motility may enable them to maintain position better in the light-rich surface waters, and more successfully make the return journey into deeper waters in order to replenish their internal nutrient stores when surface nutrients become depleted. This theory is examined using a depth-resolved model of algal dynamics. Nutrients and organic detrital matter are represented on a Eulerian grid, whilst a Lagrangian approach is used to represent dinoflagellates and diatoms. The model indicates
