The importance of benthic recruitment to the population development of Aphanizomenon flos-aquae and internal loading in a shallow lake

The recruitment of Aphanizomenon flos-aquae out of the sediments was measured in the shallow, hypereutrophic Agency Lake, Oregon. There were two main episodes of recruitment, the latter of which accounted for 8.2% of the water column population increase during its main growth phase. Phosphorus (P) content was higher in newly recruited cells than in water column cells. Recruitment during one weekly episode constituted an internal P load rate of 3.56 mg P m −2 day −1 , accounting for 27% of the corresponding increase in water column total phosphorus (TP). However, the majority of internal loading in the lake did not coincide with, and therefore could not be explained by, biotranslocation due to benthic recruitment of A.flos-aquae .