The zooplankton and other limnological features of a humic coastal lagoon (Lagoa Comprida, Mace, RJ) in Brazil

Comprida lagoon is a shallow lagoon separated from the sea by a sand barrie r. It has a brown-coloured freshwater with a high concentration of humic co mpounds. Its zooplankton community and limnological features were studied f rom March 1992 to December 1995. The lagoon was characterized by low transp arency, acid water and relative constant physical-chemical features, except during sporadic marine entrances. The zooplankton, composed of holoplankto nic and meroplanktonic forms, consisted of 60 taxa. Eleven were permanent e lements of the community: e.g. Bosminopsis deitersi, nauplii and copepodite s of `Diaptomus' azureus. B. deitersi correlated positively with the lowest pH values and with the highest total dissolved nitrogen. Only four taxa co rrelated with chlorophyll-a concentration. Pigmentation in 'D.' azureus is suggested to be as an energy reserve in a system where phytoplankton is pro bably light-limited.