Use of fluorescently labelled algae (FLA) to estimate microzooplankton grazing

Abstract

The fluorescent dye 5-(4,6-dichlorotriazin-2-yla)m inofluorescein (DTAF) was used to label a small alga (Nannochloris sp.), following the protocol of Sherr et al. (1987). A rotifer (Brachionus sp.) and a small ciliate (Euplotes sp.) ingested the fluorescently labelled algae (FLA) and demonstrated saturation kinetics. A small tintinnid ingested the FLA at rates intermediate to those of the rotifer and ciliate. Fluorescent labelling of algae is a promising technique that may be used for estimating grazing rates in a manner analogous to that discribed by Sherr et al. (1987) using fluorescently labelled bacteria (FLB).