Ammonium and phosphate regenerationby the zooplankton of an Amazon floodplain lake

Abstract

SUMMARY. 1. Regeneration of ammonium and phosphate by macro‐zooplankton (Cladocera. adult copepods. and copepodites) was measured in Lake Calado. an Amazon floodplain lake, Macrozooplanktonabundances ranged between 1×104 and 3×105 individuals m−2. 2. Phosphate regeneration ranged from 0.2 to 1.3μ mol PO4 m−2 b−1at station 1. located 2 km from the Solimoes River, and from 1.6 to8.3 μ mol PO4 m−2 h −1 at station 3, located 7 km from the SolimoesRiver. Ammonium regeneration at stations 1 and 3 ranged from 1.7 to11.9 and from 13.4 to 77.2 μ mol NH4 m−2 h−1. respectively. 3. Zooplankton regenerated ammonium and phosphate at similarrates during rising and falling waier. Regeneration by macrozooplankton was low compared to other tropical lakes and compared to microbesand microzooplankton in Lake Calado. Copyright © 1986, Wiley Blackwell. All rights reserved