Study about Top-Down and Bottom-Up Controls in Regulating the Phytoplankton Biomass in a Eutrophic Reservoir in Northeastern Brazil  

作　　者：Juliana dos Santos Severiano Ariadne do Nascimento Moura Enaide Marinho de Melo Magalhaes Viviane Lucia dos Santos Almeida 

机构地区：[1]Graduating Program on Botany,Rural and Federal University of Pernambuco,Recife,Brasil [2]Federal University of Alagoas,Institute of Biological Sciences and Health—IBSH,Maceio,Brasil [3]Department of the Environment,Prefecture of Recife,Olinda,Brasil

出　　处：《Journal of Water Resource and Protection》2012年第8期616-621,共6页水资源与保护（英文）

基　　金：supported by grants from CNPq(Brazil-ian Council for Research and Development(302068/2011-2).

摘　　要：This study aims to analyze the effects of nutrients and predation by zooplankton on phytoplankton biomass (chlorophyll a) in a eutrophic reservoir in Brazil (Apipucos Reservoir, State of Pernambuco), through experiments in microcosms. For this, samples of water were placed in 1 L Erlenmeyer flasks and kept for seven days. Treatments included the addition of nutrients (nitrogen combined with phosphorus and isolated additions of nitrogen and phosphorus), with presence and absence of zooplankton and a control which contained the reservoir water without any manipulation. The addition of nutrients did not stimulate phytoplankton growth. However, zooplankton significantly decreased phytoplankton biomass in the treatments it was added to (p < 0.05). The results of this study showed that for the reservoir studied, predation by zooplankton is the most significant factor in the regulation of phytoplankton, contradicting several studies which show that phytoplankton biomass is more strongly controlled by nutrients (bottom-up control) than by predation (top-down control).This study aims to analyze the effects of nutrients and predation by zooplankton on phytoplankton biomass (chlorophyll a) in a eutrophic reservoir in Brazil (Apipucos Reservoir, State of Pernambuco), through experiments in microcosms. For this, samples of water were placed in 1 L Erlenmeyer flasks and kept for seven days. Treatments included the addition of nutrients (nitrogen combined with phosphorus and isolated additions of nitrogen and phosphorus), with presence and absence of zooplankton and a control which contained the reservoir water without any manipulation. The addition of nutrients did not stimulate phytoplankton growth. However, zooplankton significantly decreased phytoplankton biomass in the treatments it was added to (p < 0.05). The results of this study showed that for the reservoir studied, predation by zooplankton is the most significant factor in the regulation of phytoplankton, contradicting several studies which show that phytoplankton biomass is more strongly controlled by nutrients (bottom-up control) than by predation (top-down control).

关 键 词：Chlorophyll α NUTRIENTS ZOOPLANKTON Tropical Regions 

分 类 号：R73[医药卫生—肿瘤]