There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels.

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. Peaks in abundance of up to 79 cells l -1 were observed, at the same time or subsequent to diatom blooms which were caused by episodic uplifting events during the spring and summer. The diatom blooms were dominated by the small centric diatom Thalassiosira partheneia, which was also the dominant food item found within the Noctiluca cells. A high proportion (> 80%) of Noctiluca cells contained food particles in their vacuoles during the diatom blooms, suggesting that the increase in abundance of Noctiluca was most likely stimulated by food availability. Pulses of small-sized Noctiluca cells during the diatoms blooms were indicative of this population growth. The δ 15 N isotopic similarity of the red tide cells collected from spatially and temporally distant water masses suggests that the prey of Noctiluca were derived from a single nutrient source, most likely uplifted slope water. This study shows that the predominant underlying mechanism regulating population growth of Noctiluca along the southeast coast of Australia is the uplifting of nutrient-rich slope water. The uplifting events stimulate phytoplankton blooms which in turn stimulate Noctiluca blooms.KEY WORDS: Red tides · Noctiluca · Dinoflagellates · Uplifting · Slope water · Thalassiosira Resale or republication not permitted without written consent of the publisher

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 (Ͻ525 m) were considered to be capable of population growth, in contrast to red tide cells, which are known to be large (Ͼ600 m), senescent, and the end result of a long series of biological and physical processes occurring in temporally and spatially distant water masses. Small cells were therefore considered to be located closer to the region in which growth was stimulated. The proportion of small cells in the samples was significantly correlated with relatively high concentrations of chlorophyll a. Consequently, this relationship was used to show that population growth of 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.