Carbon-Flow-Based Modeling of Ecophysiological Processes and Biomass Dynamics of Submersed Aquatic Plants

摘要

Abstract: A dynamic simulation modeling approach to describing carbon- flow-based, ecophysiological processes and biomass dynamics of freshwater submersed aquatic plant species has been developed. The models describe major, carbon-flow-based ecophysiological processes and biomass dynamics of four common freshwater species and how these are influenced by factors such as light, temperature, current velocity, dissolved inorganic carbon availability, oxygen concentration, and human influences such as management measures (changes in turbidity, mechanical harvesting, grazing, flooding). The model species are Vallisneria americana model (VALLA), Potamogeton pectinatus (POTAM), Hydrilla verticillata (HYDRIL), and Myriophyllum spicatum (MILFO). These plant species are similar in growth strategy but differ significantly in morphology and physiology. The same modeling approach was followed for all species, with species-characteristic morphology and physiology incorporated in four separate models. V. americana and P. pectinatus are considered as desirable, and H. verticillata and M. spicatum as invasive species in parts of the United States. In the models, phenology is tied to day-degree sum. This enables simulations for different sites and climates facilitating model operation. The models contain unique descriptions of (1) species characteristic vertical distribution of shoot biomass in the water column; (2) recalculation procedures of vertical distribution with daily changes in water level; (3) ibidem with daily removal of shoot biomass at various levels within the water column; (4) species- characteristic epiphytic light interception; (5) species-characteristic effects of current velocity on photosynthesis; (6) removal of periodic shoot and tuber/root crown biomass; and (7) relationships of plant process parameters with site-specific climate by linkage with formatted weather files and calculation of latitude-specific effects on day length.