A plantonologist specializes in the study of plankton, which includes both phytoplankton (plant-like organisms) and zooplankton (animal-like organisms) in aquatic environments. They conduct research on the Biology, ecology, and distribution of these microscopic organisms, often examining their roles in food webs, nutrient cycling, and responses to environmental changes. Their work can contribute to our understanding of marine ecosystems, climate change, and the health of oceanic and freshwater systems.