Temporal and vertical variation of phytoplankton and zooplankton in two tropical reservoirs with different trophic states.

In tropical reservoirs, limnological factors are responsible for changes in plankton and vary at temporal and vertical scales. The aim of this study was to evaluate the effects of temporal and vertical variation of the water column on phytoplankton and zooplankton dynamics in two tropical reservoirs (mesotrophic and supereutrophic) in Northeastern Brazil. Monthly collections from three depths in the limnetic region of the reservoirs were performed to analyze the phytoplankton, zooplankton, and limnological variables.

Effects of the manipulation of submerged macrophytes, large zooplankton, and nutrients on a cyanobacterial bloom: A mesocosm study in a tropical shallow reservoir.

Biomanipulation is an efficient tool to control eutrophication and cyanobacterial blooms in temperate lakes. However, the effects of this technique are still unclear for tropical ecosystems. Herein, we evaluated the effects of the biomanipulation on cyanobacterial biomass in a tropical shallow reservoir in Northeast Brazil.

Biometric and physiological responses of Egeria densa Planch. cultivated with toxic and non-toxic strains of Microcystis.

Cyanobacterial blooms are becoming increasingly common in aquatic environments around the world, mainly due to eutrophication and climate change. Cyanotoxin-producing strains (e.g.

Cyanobacteria, microcystins and cylindrospermopsin in public drinking supply reservoirs of Brazil.

Brazil has a history of blooms and contamination of freshwater systems by cyanobacterial toxins. The monitoring relevance of toxins from cyanobacteria in reservoirs for public supply is notorious given its high toxicity to mammals, included humans beings. The most recurrent toxins in Brazilian water bodies are microcystins (MC).

Phytoplankton community of Reis Lake in the Brazilian Amazon.

Reis Lake is located in the municipality of Caracaraí, state of Roraima (Brazil) and is subject to fluctuations in water level. The aim of this study was to analyze the structure of the phytoplankton community on the nictemeral and seasonal scales and determined the influence of limnological variables. Sampling was performed in the rainy season (June/2006) and dry season (November/2006), considering two nictemeral cycles.

Plankton diversity and limnological characterization in two shallow tropical urban reservoirs of Pernambuco State, Brazil.

Plankton diversity, physical and chemical variables and chlorophyll a were analyzed in two shallow urban reservoirs with different trophic degrees on Pernambuco State, northeastern Brazil. High eutrophication levels were observed in Apipucos reservoir, while Prata reservoir was considered oligotrophic. Values reported for physical and chemical variables and chlorophyll a differed among the studied ecosystems.