Submerged macrophytes, phytoplankton and zooplankton in tropical reservoir

Abstract

Submerged macrophytes, zooplankton and phytoplankton surround reservoirs are still need knowledge about ecology and influence in water quality in reservoirs of America Latina. The control of the biomass formation, low nutrient loadings, algal growth and diversity are key points to acquire water quality. We investigated evidences of submerged macrophytes enhance water quality and planktonic assemblages in two bays surround reservoir. Samples for water transparency, nutrients (phosphorus and nitrogen mg/L-1), phytoplankton, and zooplankton were collected inside macrophytes between littoral and limnetic areas. Analyses with Standard Protocols were applied to make comparisons of these parameters. In the study areas the water bodies were Super and Eutrophic, the Secchi disk was high (3.8 and 3.9 m), low concentration of phosphorus (means= 0.03 and 0.05 mg/L-1) and nitrogen (0.4 and 0.9 mg/L-1). Chlorophyll-a exhibited high biomass formation during the dry period (49 and 61 μg/ L-1). Egeria densa cover a wide range in littoral areas (66% and 40%). Phytoplankton was represented by 13 species, including Cyanophyta (5,292 to 717 cell /mL-1) in high densities. Zooplankton comprised 77 species of Rotifera, 18 of Cladocera and three Copepoda, and densities varied between 3,711 and 2232 org.m-3 in the littoral areas. The Re-oligotrophication and restoration of these bays can be used combining biological methods knowledge and technical experimentation. New approaches to aadapted management measures to advance research and to improve water quality is a next step in a near future of reservoirs from Northeast Brazil.