Microalgal populations of three New Zealand coastal locations: forcing functions and benthic-pelagic links

Abstract

I investigated spatial and temporal variability in benthic and pelagic (phytoplankton) microalgal assemblages in 2 harbours and a coastal embayment off the east coast of the North Island of New Zealand in late spring, summer and autumn. For the first time pelagic microalgal assemblages were sampled just above the sediment in the layer from which suspension feeders are likely to feed (~10 cm). Benthic microalgal assemblages were also assessed within the sediments. Strong links were observed between pelagic and benthic microalgal populations, with the amount of benthic microalgae found in suspension correlated with current speed and turbidity. Conversely, a number of species found within the benthic counts were tychopelagic species whose life habit is to rely on currents which re-suspend them from the benthic to pelagic environment. In late spring, pelagic water samples from 1 harbour and the embayment it opened into were dominated by dinoflagellate taxa, while diatoms dominated the second harbour location. In autumn, all the locations were dominated by diatom taxa but the 2 harbours were most similar in community composition. In summer, local conditions favoured the development of different microalgal populations in each location. Both pelagic and benthic microalgal assemblages generally decreased in similarity as spatial scale increased, with populations being most similar within a sampling site and least similar between locations. Benthic microalgae assemblages were more variable than pelagic assemblages within and between sampling sites at the locations, but had a greater similarity between locations (40 to 64%). Our results provide a new insight into the scales of variability of microalgal populations within and between different nearshore environments, and identify some of the forcing factors that drive changes in microalgal composition. By sampling microalgal populations just above the sediment we have begun to characterise the microalgal communities that sustain suspension feeders.

Microphytobenthic dynamics in a Wadden Sea intertidal flat – Part II: Seasonal and spatial variability of non-diatom community components in relation to abiotic parameters

“…A fourth subsample was taken for MPB identification and enumeration, using the method described by Safi (2003). For preparation the samples were initially re-suspended in approximately 40 ml of sterilized seawater and preserved with Lugol's solution.…”

Spatial variation of chlorophyll on estuarine mudflats determined by field-based remote sensing

“…BB had much greater variation than any other location). Several large-scale properties or processes could be influencing differences among locations, including variation in sediment characteristics (Brotas et al 1995), hydrodynamic conditions (Colijn & Dijkema 1981, Safi 2003, tidal regime or wind causing suspension of MPB into the water-column (de Jonge 1995), salinity and nutrient gradients (Underwood et al 1998), the intensity of urban development, and history of land-use. KBE and KBW are on opposite sides of a Bay (Fig.…”

“…The distribution of MPB is, however, extremely patchy over space (Admiraal 1984, Saburova et al 1995, Seuront & Spilmont 2002 and time (MacIntyre & Cullen 1995, Serodio et al 1997. Variability in distribution is governed by many diverse biotic and abiotic processes, including diel rhythms of vertical migration (Consalvey et al 2004), hydrodynamic factors (Safi 2003), size of sediment grains (Colijn & Dijkema 1981), salinity and nutrient gradients (Underwood et al 1998), small-scale variations in topography (Plante et al 1986), and shading (Stutes et al 2006).…”

“…Other studies have tended to focus upon variability at larger (10s m to km) scales (e.g. Light & Beardall 1998, Safi 2003.…”

A Pilot Study on the Effects of Temperature on the Blooms of the Benthic Mucilage-Forming Microalga Chrysophaeum taylorii

“…With regard to microalgae, in particular, as sea water temperature is currently considered as one of the main environmental factors determining the abundance and composition of microphytobenthos on the substratum [2][3][4][5], climate changes seem to be among the major driving forces behind the stimulation, distribution and intensification of their blooms in the last decades [6]. Indeed, warmer sea water temperatures result in expanded ranges of warm water microalgal species, which blooms at latitudes higher than their original ones seem to be almost completely temperature-dependent [5].…”