Chlorophyll pigments in the Central Amazon lakes ecosystem

Summary

From this study it is evident that rapid recycling of organic matter in the upper photic zone maintains an ecological equilibrium in the Amazon aquatic ecosystem. Estimation of chlorophyll-a should be corrected for pheo-pigments before using it as an index of phytoplankton biomass. From the data of Lago Janauari on the chlorophyll and POC, it implies that large chlorophyll concentrations do not have such correspondingly large carbon values. Low POC: chlorophyll ratios in the Central Amazon lakes during low water level period imply the occurrence of an increasingly active phytoplankton population and the presence of relatively larger quantities of autochthonous detrital POC as a result of this increased growth. It is observed that the relationship between bacteria and phytoplankton is complex and tends to vary according to the lake environment. The following relationships were evident from this study: (a) high bacterial densities coincided with high chlorophyll, (b) low bacterial densities coincided with high chlorophyll, (c) high bacterial densities coincided with low chlorophyll and (d) low bacterial densities coincided with low chlorophyll. There is a good evidence that water level fluctuations are a very important ecological parameter which regulate the microbiological productivity of aquatic ecosystem in the Central Amazon lakes.