Simulation Model for Growth of the Submersed Aquatic Macrophyte American Wildcelery (Vallisneria americana Michx.)

摘要

A simulation model for biomass dynamics of the submersed macrophyte Vallisneria americana Michx. is presented. The model (VALLA) is based on carbon flow through the vegetation in meter-squared (m') water columns. It includes descriptions of several factors that affect biomass dynamics, such as site- characteristic changes in climate, water temperature, water transparency, water level, pH, and oxygen effects on CO, assimilation rate at light saturation, wintering strategies, mechanical control (removal of shoot biomass), grazing, and climate. The characteristics of community and site can be easily modified by the user. VALLA incorporates insights into the processes affecting the dynamics of an American wildcelery community in relatively shallow, hard water (0.2-6 m depth; DIC concentration> 0.8 mmol and pH ranging from 7.6 to 9.4), under ample supply of nitrogen and phosphorus in a pest-, disease-, and competitor-free environment under the prevailing weather conditions. It has been calibrated on data pertaining to a wildcelery community in Chenango Lake, New York At this site, growth starts from the subterranean tubers alone. Plant biomass usually peaks once a year, in July, and intensive downward transport of soluble carbohydrates occurs after anthesis, used for the formation of tubers that grow into the sediment.