Temperature and turbidity as drive forces to the growth of Egeria densa (Planchon) under to controlled conditions

Abstract

The development of an aquatic community may reflect anthropogenic influence on adjacent areas of a freshwater system. Mathematical modeling of the growth of a species is a predictive tool that can be useful for planning management strategies In this study, a kinetic model was used to evaluate the growth of submerged macrophyte Egeria densa under laboratory conditions that simulates growth in function of the temperature and turbidity increasing as drive forces to the growth. Incubations were prepared with E. densa individuals which were maintained in controlled condition (25 and 27 °C and four turbidity conditions (0% - the control, 18.5 %, 37 % and 55.5 %). Mathematical modeling of macrophyte turbidity growth indicated that macrophyte growth exhibited an average doubling time (dt) varying from 7.83 and 12.04 days. Increased turbidity resulted in growth stress for E. densa. This species showed great temperature sensitivity (Q10 = 3.0) and higher growth potential at 27 °C when compared to 25 °C, a situation verified by growth coefficients (90.44 % more). The soil used (Quartzarenic Neosol) contributed to the growth of E. densa, due to the nutrient content in its composition. Increased turbidity resulted in stress for E. densa, resulting in changes of the growth patterns. The results generated may contribute to the development of new approaches and provide support for management, especially in relation to neotropical aquatic systems located in the Brazilian savanna.