| This thesis is about ocean ecosystem biology that is relevant to the global climate. In particular, it is about developing a relatively simple predictive understanding of the biology of the upper ocean so that its role in the air-sea balance of CO;In Chapter 1, I present an overview of the strategy used to develop and evaluate the models presented in this thesis. In Chapter 2, I present a new ocean ecosystem model developed and calibrated to field data from a site near Bermuda. This model is simpler than most comparable models and yet fits the data better than comparable models. Its ability to fit the data relies in large part on the effects of biodiversity and phytoplankton physiology not in comparable models. In Chapter 3, I refine and extend that model to simultaneously fit field data from two qualitatively different sites. An important feature of this extension is the inclusion of iron limitation as a hypothesis for why macronutrients are not typically depleted at one of the sites. In Chapter 4, I present data on the variability of the chlorophyll-to-biomass ratio of phytoplankton. Variability in the chlorophyll-to-biomass ratio is an important prediction by the new models of a physiological characteristic of phytoplankton which is absent from the majority of comparable models. In Chapter 5, I describe preliminary results from coupling these ecosystem models to a general circulation model (GCM) of the North Atlantic. GCM studies are crucial to extend model predictions over large areas and to couple the models of ocean ecosystem biology to models of potentially changing ocean circulation. |
