Harmful algal blooms (HABs) are extreme biological events that can damage the environment, endanger marine life, alter biodiversity, and pose severe risks to human health. The connection between HABs and coastal processes, nutrient enrichment, and climate forcing at the land-sea interface are critical lines of investigation. An increasingly important tool for expanding our heuristic view of phytoplankton community structure is the use of physical-biological models. One of the central emphases of the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) program established by the Scientific Committee on Oceanic Research (SCOR) and International Oceans Commission of UNESCO is the development of models that advance predictive capabilities and mechanistic understanding of HABs. In a recent special issue on HAB modeling in the Journal of Marine Systems, McGillicuddy outlined the broad scope of approaches now applied to understanding the ecology and evolution of phytoplankton communities, physiological adaptation, the role of advection and diffusion processes, and the effects of eutrophication, to name a few. These range from conceptual and empirical to mechanistic and three-dimensional numerical models. Ideally, biological models will have a mechanistic component based on first principles of planktonic life cycles and physiology, however insufficient data for many species have hampered the development of robust, mechanistic models. In light of this, many investigators have focused on empirical or statistical methods to parameterize the unique relationships between environmental factors such as nutrients and temperature and the individual species responses within a defined geographic region.