Population growth and transport of the red tide dinoflagellate, Noctiluca scintillans, in the coastal waters off Sydney Australia, using cell diameter as a tracer
Spatial abundance patterns of the heterotrophic dinoflagellate, Noctiluca scintillans, were investigated along the southeast coast of Australia to address the hypothesis that population growth of Noctiluca is driven by anthropogenic eutrophication. Abundance patterns were related to the immediate physical flow field and not the conditions conducive to growth. Noctiluca cells were advected southward with the East Australian Current, which was the dominant transport vector for the cells in this region. Areas of population growth of Noctiluca were identified by variations in cell‐size distributions. Small cells (Noctiluca may be stimulated by an increase in chlorophyll a due to sewage discharge, although the prevailing hydrological conditions determine the likelihood of such impacts. High chlorophyll a concentrations within estuaries were also found to sustain a stable but low standing stock of Noctiluca, which may seed oceanic stocks. Thus, by examining cell size rather than abundance distributions, we identified and interpreted the variance in the spatial abundance patterns of Noctiluca within a dynamic hydrological environment.