Emilie Luna-Laurent, EPA:
We're here at one of our sites in Port Phillip Bay where we've been monitoring water quality since the 1980's as part of a network of sites across the state of Victoria. The data we've collected over the years has been very helpful in determining long term trends of what is affecting the marine environment.
There are lots of activities and processes happening around the bay. For example we have recreation, aquaculture but also shipping. The long-term monitoring we've been doing helps us understand and manage those processes. In addition to long term monitoring, in the future this vessel will enhance our capability to investigate pollution hotspots.
Randall Lee, EPA:
This is an instrument we've been using since the early 2000's called a CTD or a conductivity temperature depth probe. It is lowered through the water column to measure really important water quality properties such as oxygen levels and algae growth levels.
This area is important because we've got a very large flow of nutrients coming in from the Yarra river and storm water in the region and it's an early warning measure of how much growth we're getting in the bay which can deplete the oxygen levels and affect fish and crustacean.
Neil Blake, Port Phillip Baykeeper:
One of the most promising developments is the strong working relationship between the EPA and community groups such as the EcoCenter and Beach Patrol and others. We've been getting millions of particles of plastic being washed into Port Phillip Bay every year for quite a number of years now and at last that issue is starting to be measured by use of the Manta net which can actually give us a record of
how many particles and the different types of plastic that are actually in the water column.
The Manta net is designed to skim the surface of the water column and pick up the plastics that are floating within the top 200 millimetres and so that gives us a good picture about what sorts plastics are getting into the bay. That way we can actually develop some strategies around how we can reduce them and prevent them from getting into the water in the first place and that we might be able to reduce their numbers in the future.
Emilie Luna-Laurent, EPA:
Sediment is like underwater dust that collects on the seafloor. It's a collection of sand, organic matter, soil and microorganisms. Here we are in a hot spot where the Yarra meets the bay causing a lot of sediment to drop on the seafloor and a lot of pollutants to accumulate in this particular area.
A lot of underwater plants and organisms rely on the sediment and live in the sediment and sediment is particularly attractive to pesticides and heavy metals because that's where it accumulates, so it is important for us to look at sediment quality and also water quality.
Sediments accumulates over a long period of time so it's a slow process and we would typically sample sediments over periods of three to five years. The tool that we use to collect sediment is a little instrument that we drop through the water column to the seafloor and it collects the top layer of sediment
representing the latest pollution which occurred. The way we process the sample is to put them through a fine sieve. Sediment samples can be processed on board. Here we are using a sieve to specifically screen out micro plastics.
Randall Lee, EPA:
Sometimes the balance of oxygen could be disturbed. After an algal bloom we usually see a drop in the dissolved oxygen levels at depth. What happens is the microscopic algae at the surface, they die and they fall to the bottom where it's consumed by bacteria.
The bacteria use a lot of that oxygen up to eat away the algae and this reduces the oxygen levels for the fish and crustacean which can cause harm.
If there's not enough oxygen, the chemistry of the water changes. This can make pollutants like heavy metals in the sediments become available to the marine fauna. This means the metals can be absorbed into the bodies of fish or other animals and accumulate all the way up the food chain to humans.
bar-ba-ka broadens our marine monitoring capabilities by enabling us to:
- monitor monthly at our long-term fixed sites
- investigate marine issues
- respond to environmental emergencies
- identify pollution hotspots
- manage compliance investigations.
The boat is moored at Williamstown, to allow quick access to Port Phillip Bay.
EPA worked closely with the Boon Wurrung community and Aboriginal cultural consultants to name our boat bar-ba-ka, which means 'porpoise'.
Equipment and capability
bar-ba-ka houses a ‘floating lab’ with onboard monitoring and sampling equipment. It can deploy scientific equipment such as instrument moorings (anchored sensors) and towed vehicles for detailed underwater assessments. The wide platform allows deployment of large equipment such as automated underwater vehicles, and it can act as a support vessel for diver investigations.
At the heart of the boat is an automated water quality system that continuously maps water quality as the vessel undertakes any activity.
Nautical features and performance
bar-ba-ka is an efficient, diesel-powered aluminium catamaran (twin hulls). These features provide excellent stability and seaworthiness, and a range of more than 750 nautical miles.
This allows it to operate in all Victorian marine waters and beyond to 100 nautical miles offshore.
At just under 12 metres long, bar-ba-ka has a cruising speed of 11–12 knots and top speed of 20 knots. It has accommodation for two crew members and can carry up to eight other people.
This page was copied from EPA's old website. It was last updated on 18 October 2016.
Reviewed 15 September 2020