How light and nutrients affect life in a closed bottle
Kooijman, S.A.L.M. and Nisbet, R.M. 2000. How light and nutrients
affect life in a closed bottle. In: Jørgensen,
S.E. Thermodynamics and ecological modelling. CRC Publ., Boca
Raton, FL, USA, pp 19 - 60.
Abstract
We evaluate the mass and energy turnover in a canonical community that
lives in a closed bot- tle at steady state. We use daphnids, algae and
bacteria, called the DAB-community, as example of a canonical
community consisting of consumers, producers and decomposers. We built
up the system in four steps, starting from the Monod model for the
three biota, and include reserves, maintenance and population
structure for the daphnids, where the individuals follow the rules as
speci ed by the Dynamic Energy Budget theory. This theory provides the
theoretical foundation for the widely applied method of indirect
calorimetry, that relates dissipating heat linearly to carbon dioxide
production, oxygen consumption and ammonia production.
Our evaluation illustrates the application of thermodynamical
principles in a very simple, spatially homogeneous, but
non-degenerated community. In the full system, we follow the fate of
16 compounds partaking in 16 chemical transformations. Dissipating
heat turns out to be a useful measure for the rate of living, which
increases almost proportional to light intensity when e ects of
temperature are excluded. We also nd that dissipating heat increases
for decreasing total nitrogen. We derive explicit expressions for
nutrient and biomass turnover and show their relation with dissipating
heat, and community structure.