Dynamic modelling of photosynthesis in marine and estuarine ecosystems

Abstract

The relationship between primary productivity and light intensity is usually modelled as a static representation of photosynthesis, assuming that the parameters describing the response to light are constant. However, these parameters have a dynamic behaviour justifying the development of dynamic models in order to improve the description of photosynthesis in the sea.

In this work a mathematical model is used to simulate several situations where the phytoplankton exposure to light is controlled by the temporal variation of light intensity and the vertical advective and diffusive flux. The model includes both a static and a dynamic description of photosynthesis. It uses object‐oriented methods to switch between different types of productivity response to light intensity and to potential photoinhibition effects.

The main conclusions emerging from the simulations performed are that the dynamic behaviour of the production–light curves is relevant in the simulation of primary productivity, and that this relevance is more pronounced under high light conditions and/or in the absence of vertical mixing. It is suggested that large scale models, where the time and spatial scales are too large to include the dynamic behaviour of the photosynthetic light response, may be parameterized by smaller scale simulations including the mentioned dynamic behaviour.