Plankton dynamics in Leschenault Inlet and comparisons with the Peel-Harvey estuary

Hosja, W. and Deeley, D.M. (2000) Plankton dynamics in Leschenault Inlet and comparisons with the Peel-Harvey estuary. Journal of the Royal Society of Western Australia, 83 . pp. 357-363.

Abstract

Concerns over weed accumulations on beaches and possible nutrient enrichment prompted an investigation into phytoplankton dynamics of Leschenault Inlet. The composition of the phytoplankton community, its relative density and the amplitude seasonal density changes were investigated over an eighteen month period. The zooplankton community was also sampled during summer to identify dominant organisms.
The phytoplankton community was dominated by marine and estuarine diatoms for most of the year. Species having a freshwater affinity were observed for short periods during winter, and included diatoms, dinoflagellates, cyanophytes and cryptophytes. These species were probably transported into the estuary with winter runoff from streams throughout the catchment. There was a high proportion of normally benthic or epiphytic species in surface waters consistent with very shallow depths and significant wind mixing for much of the year. Some of these species were observed attached to seagrass leaves.
There was considerable spatial and temporal variability in cell densities and species numbers throughout the estuary. Short-term blooms in excess of 5 000 cells mL-1 were observed in the estuary during autumn and spring. The presence of blooms indicates that Leschenault Inlet may be experiencing some nutrient enrichment although greater species numbers than observed in the highly nutrient enriched Peel and Harvey estuaries suggest that Leschenault Inlet may only be mildly nutrient enriched. Further investigations into sediment and nutrient inputs and the autecology of phytoplankton indicator species may assist in determining the nutrient status of Leschenault Inlet.

Item Type:	Journal Article
Murdoch Affiliation(s):	School of Environmental Science
Publisher:	Royal Society of Western Australia
Copyright:	© Royal Society of Western Australia
URI:	http://researchrepository.murdoch.edu.au/id/eprint/17623

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