10. Process-Based Modeling of Nutrient Cycles and Food-Web Dynamics

Mathematical models are indispensable for addressing pressing aquatic ecosystem management issues, such as understanding the oceanic response to climate change, the interplay between plankton dynamics and atmospheric CO₂ levels, and alternative management plans for eutrophication control. The appeal of process-based (mechanistic) models mainly stems from their ability to synthesize among different types of information reflecting our best understanding of the ecosystem functioning, to identify the key individual relationships and feedback loops from a complex array of intertwined ecological processes, and to probe ecosystem behavior using a range of model application domains. Significant progress in developing and applying mechanistic aquatic biogeochemical models has been made during the last three decades. Many of these ecological models have been coupled with hydrodynamic models and include detailed biogeochemical/biological processes that enable comprehensive assessment of system behavior under various conditions. In this chapter, case studies illustrate ecological models with different spatial configurations. Given that each segmentation depicts different trade-offs among model complexity, information gained, and predictive uncertainty, our objective is to draw parallels and ultimately identify the strengths and weaknesses of each strategy.