Mixotrophy in Bloom-forming Dinoflagellates: Interactions of C, N and P
Mixotrophy, the utilization of alternate modes of nutrition, is an important but poorly understood aspect of the physiological ecology of bloom-forming, photosynthetic dinoflagellates. Harmful algal blooms appear to increasing in frequency world-wide with potential effects on whole ecosystems. One common attribute shared by most harmful algal taxa is mixotrophic tendencies. Many red-tide dinoflagellates eat. Complex interactions between photosynthesis, feeding, and uptake of inorganic and organic nutrients may provide the nutritional flexibility that gives dinoflagellates advantages over other phytoplankton in eutrophic, but highly variable environments with respect to resources.
As part of an ongoing project, phagotrophic mixotrophy is being investigated in Prorocentrum minimum and Gyrodinium galatheanum (syn., Gymnodinium galatheanum; also has been called Gyrodinium or Gymnodinium estuariale in Chespeake Bay region), two red-tide dinoflagellates. Preliminary evidence indicates that feeding is stimulated by inorganic nutrient limitation in red-tide dinoflagellates, and that feeding interacts with photosynthetic carbon metabolism. These aspects of the physiological ecology of red-tide dinoflagellates will be experimentally investigated in the laboratory.
