Chlorophyll production, in response to nutrient additions, by the algae in Lake Rotorua water

Abstract

Batch cultures of water and algae from Lake Rotorua were subjected to nitrogen, phosphorus, and trace element additions, singly and in combination, at monthly intervals between June 1975 and May 1976. The algal responses to the additions were assayed after 5 d incubation, by extracting the chlorophyll from the algae and estimating the concentration by fluorescence. The chlorophyll production consistently responded positively to the addition of nitrogen, while responses to the addition of phosphorus and trace elements were minor by comparison. Although the chlorophyll responses to nitrogen may not have been paralleled by actual growth, the consistent pattern of behaviour by algae in the batch cultures was interpreted as evidence of persistent shortage of nitrogen in the Lake Rotorua environment.