EXPERIMENTAL MESOCOSM STUDY OF THE SEPARATE AND INTERACTION EFFECTS OF PHOSPHORUS AND MOSQUITOFISH (GAMBUSIA-AFFINIS) ON PLANKTON COMMUNITY STRUCTURE

Total phosphorus (TP), chlorophyll, cryptomonads, unicellular green algae, unicellular blue-green algae, colonial blue-green algae, filamentous blue-green algae, chironomid tube length, cladocerans, fish density, and fish biomass were significantly enhanced in the presence of phosphorus addition. Total nitrogen (TN), TN:TP ratio, Secchi depth, chrysophytes, and periphytic diatoms were suppressed in the presence of phosphorus addition. Diatoms, filamentous blue-green algae, chrysophytes, periphytic unicellular and colonial green algae, periphytic filamentous blue-green algae, and rotifers were enhanced in the presence of mosquitofish. Secchi depth, TN:TP ratio, cyclopoid copepodids, nauplii, cladocerans, and chironomid tubes were suppressed in the presence of mosquitofish. There were significant phosphorus × mosquitofish interaction effects for TN:TP ratio, chrysophytes, dinoflagellates, periphytic colonial green algae, cladocerans, and chironomid tubes. -from Authors