The size-based dynamics of plankton food webs. I. A simulation model of carbon and nitrogen flows

Abstract

A general, size-based simulation model is developed to investigate the dynamics of carbon and nitrogen flows in plankton communities. In the model, community structure and transfer processes are all size-dependent, and all model parameters are determined by body size, using empirically determined relationships calculated from published data Major flows include carbon fixation, release of photosynthetically produced dissolved organic carbon (PDOC), nitrogen uptake, respiration, excretion, predation, senescence and sinking. Because the model is based on general ecological principles and not on a specific ecosystem or data set, it can be used to simulate interactions within plankton communities of any ecosystem. The structure of the model can easily be altered to incorporate fewer or more size classes, or different size ranges of organisms. The program adjusts interactions between different components to allow for changes in the number of size classes, and new parameters are estimated, based on mean organism size A standard simulation is described, which serves as the basis for comparing output from a sensitivity analysis. The model is robust with respect to most parameters. Important factors which affect model output include estimates of various rate parameters (which may be altered by environmental effects), shapes of initial biomass distributions (seeding effects), and wet mass to carbon conversion functions. The model is a useful tool to assist in analysing and interpreting carbon and nitrogen flows in planktonic ecosystems.

Temporal changes in total and size-fractioned chlorophyll-a in surface waters of three provinces in the Atlantic Ocean (September to November) between 2003 and 2010

“…In addition to phytoplankton biomass, community size structure also plays a pivotal role in marine biogeochemistry. Phytoplankton cell size influences metabolic rates, growth and affinity for nutrients (Chisholm, 1992;Marañón, 2009), the structure and trophic interactions of the marine food web (Maloney and Field, 1991) and the export of carbon to the deep-ocean (Guidi et al, 2009;Laws et al, 2000). It is for these reasons that phytoplankton biomass and size structure are recognised as key ecological indicators in the marine environment (Platt and Sathyendranath, 2008).…”

WEST: A northern California study of the role of wind-driven transport in the productivity of coastal plankton communities

“…al 1986, Franks et al 1997 to models that partition the NPZ components into additional boxes (e.g., Wroblewski 1977) or models of increasing complexity (and boxes) that include the 7 microbial web (e.g., Fasham, et al 1990, Moloney andField 1991). These models have been coupled with a variety of upwelling circulation models, depending on the focus of study, ranging from simple "conveyor belt" models to fully 3-dimensional simulations.…”

Nutrient enrichment, habitat variability and trophic transfer efficiency in simple models of pelagic ecosystems

“…We set the sinking rates (e.g. Scavia et al 1988, Moloney & Field 1991) and the zooplankton food-preference coefficients (e.g. Scavia et al 1988, Andersen & Nival 1989 substantially higher for the large than the small phytoplankton (Table 1).…”

“…Moloney & Field 1991). We also used the 2-compartment (P-Z) model to test the generality of our formulation for P self-limitation by replacing the quadratic algal senescence term with a self-shading expression in the algal growth term.…”