9. Spatially Explicit Modeling of Productivity in Pool 5 of the Mississippi River

The restoration and management of large rivers is difficult because such rivers have dynamic ecosystems and complex organic carbon cycles. Furthermore, energy flow is controlled by biotic and abiotic factors, similar to terrestrial systems, and also by hydraulic factors. There are three commonly discussed theories that attempt to describe productivity in large rivers, but none provides a generalized mechanism that can be applied across all rivers and all seasons. This chapter discusses a spatially explicit carbon-cycle model that simulates patterns of productivity in pool 5 of the Mississippi River. The model, developed using NetLogo (http://ccl.northwestern.edu/netlogo/), incorporates both ecological and hydraulic processes for the purpose of representing the complexity of the Mississippi River carbon cycle and pinpointing key sources of productivity within it. This model can serve as a simple and effective tool for use by researchers and students who are interested in studying river productivity, and it is readily adaptable to a variety of river ecosystems simply by substituting hydrology inputs such as maps of depth, velocity, and flow direction.