A study of the response of phytoplankton to rainfall in Sydney Harbour on 21st October 2004 is reported here.
Sydney Harbour is an important port and recreational region for the city of Sydney. Phytoplankton can be used as one of the indexes of water quality. The concentration of phytoplankton is influenced by the nutrients in the water and the amount of nutrients is thought to alter according to the urban and industrial wastes that drain from the city of Sydney.
The amount of phytoplankton before and after rainfall at Pyrmont in Sydney Harbour was observed. The concentration of chlorophyll after a period of rainfall from the 15th October to the 4th of November 2004, as measured from the surface to 7m deep, was almost 5 times as much as that as before the rain event. The maximum chlorophyll concentration observed by fluorometer was 27 [ug/litre].
The measurements of phytoplankton were done at a wharf at Pyrmont in Sydney Harbour. The concentrations of phytoplankton were measured at several depths of water, from the surface to 7m using fluorescence emission. Measurements were done at the data rate of 2 times per second. For each depth, 50 samples were collected. To get the clean water offset information, the measurements were done in the swimming pool at the Sydney University Aquatic Centre where the water was disinfected. The clean water offset at the swimming pool was around 110.
An ECO Chlorophyll Fluorometer (Western Environmental Technology Laboratories Inc.) was used to analyse the measurements. The instrument consists of optic head, cable, switch, battery, and USB connector. A weight was attached at the end of a cable so that the fluorescence meter did not move much in response to a current of water.
The purpose of this study is to determine the role of storm water drainage on harbour phytoplankton.
University of Sydney