Seawater source and treatment

The marine microalgae species maintained by ANACC are grown using unpolluted oceanic seawater therefore, strictly speaking, we are using an enrichment medium.  Artificial seawater media in contrast is composed of marine salts and nutrients added to pure freshwater. Artificial seawater is only necessary where a clean natural seawater source is unavailable or in particular research studies (e.g. trace metal studies) where the exact composition needs to be controlled. Our collection source takes advantage of CSIRO Hydrochemistry group’s monitoring station on the seaward side of Maria Island off the continental shelf along the east coast of Tasmania. The salinity at this site is ~33-36 Practical Salinity Units.  This off-shore site has very low concentrations of metal and organic pollutants therefore making it suitable as the base medium for a wide range of marine microalgae species.

The seawater is collected in 20 L black polyethylene carboys acid washed prior to collection and then stored at 4 0C until needed. Then it is treated using a filtration series incorporating three 12” Millipore™ cartridge filters (5 µm prefilter, activated charcoal filter for organics removal and a Durapore 0.45µm filter) and finally a Millipak  40TM 0.22 µm disc filter.