GROWTH OF THE AQUATIC PLANT MYRIOPHYLLUM-SPICATUM IN A LITTORAL AREA OF THE HUDSON RIVER ESTUARY

Growth of Myriophyllum spicatum L. in an estuarine (0-6% salinity) littoral area was examined for a 1 year period. Standing crop of the plants ranged from 0 g/m2 in winter to 60 g/m2 (dry wt) in summer. A significant reduction in standing crop during August could be the result of high temperatures (up to 42°C) observed in the plant stand just prior to the reduction in standing crop. Maximum standing crop of M. spicatum in this study was less than that observed for this plant in some freshwater lakes and ponds. Lower standing crop of M. spicatum in the present study is attributed to physical factors. The estuarine littoral area experienced lower light penetration, more dynamic currents, and coarser sediments than the other areas studied. A negative correlation between percent composition of leaf biomass and total plant standing crop is attributed to sloughing of old leaves as the plant stems grow. Particulate material on the plants ranged between 0.8 and 3.8 g/g M. spicatum biomass and constituted more matter in the littoral area than did the plants. © 1979.