Camden Haven High School logo

Camden Haven High School

Camden Haven High School

Aim for the Highest

Students Help Revive Local Lakes

Students from CHHS have the unique opportunity to gain real-world experience by taking their classroom knowledge of Marine Biology and applying it to the local area, assisting in the ongoing research at Lake Cathie and Lake Innes.

“They are learning a whole new set of skills and its good for them to be helping the wider community on this project,” said Marine Biology teacher Dr Deb Geronimi.

Although the lake system is managed by four stakeholders, there have been no tests done at Lake Innes, where students will travel to take water samples at the end of May.

“Students are getting hands-on research for a real problem,” said Deb.

Senior students have this unique opportunity under direction of Marine Biology teacher Dr Deb Geronimi, who did her PhD in estuary microbiology.

“We are lucky to have her,” said Year 12 student Holly Dodge about her teacher, “not many people would be able to understand the problems of the lake the way she does.”

Students will launch kayaks from Lake Cathie and travel up to Lake Innes, taking water samples and video recordings of the conditions as they go to send to the stakeholders managing the lake system.

“It’s good to be involved,” said Marine Biology student Holly Dodge.

“Everything helps, especially the water testing its giving facts to the Revive Lake Cathie group to back up what they’re trying to prove and fix,” she said.

Earlier in May, students collected water samples from the surface of five locations around Lake Cathie. They tested the salinity, pH, and levels of nitrates, nitrites and ammonia, with some alarming results.

Students discovered that the salinity was dangerously high, measuring 47 parts per thousand in some areas compared to the ocean salinity of 35 parts per thousand. This means that for every 100 litres of water, there is an additional 1kg of salt.

The salinity affects the pH of the water as salts can make the water more alkaline. When students tested the pH at the lake, some areas were off the scale of their equipment, measuring over pH 8.8 compared to the usual pH of 8.2. Also affected is the oxygen levels dissolved in the water and sediments, which allow sulphate reducing bacteria to grow in these conditions, raising the levels of hydrogen sulphides.

These precarious conditions are toxic to most living things, with the presence of ammonia in some spots, which is indicative of dying fish, crabs and oysters, identified by students on the shores of the lake.

Locals and visitors avoided swimming over the summer due to dead fish that had washed up and the unappealing colour of the water due to Tea Tree run-off.

Students will submit their results to Revive Lake Cathie Community Group and Port Macquarie Hastings Council to assist in the planning for a long-term solution for the area.

The Lake Cathie system management is the responsibility of Port Macquarie Hastings Council, National Parks and Wildlife Services, Office of Environment and Heritage and the NSW Fisheries and Department of Industry.

The lack of water testing in Lake Innes could be a result of the lack of ownership from one of these stakeholders so students are taking the initiative to test the waters themselves.

A highly debated subject, the health and management of these lakes is at the forefront of the Revive Lake Cathie Movement that has involved experts from a variety of fields.

The recent drought has had a detrimental effect on the lake ecology due to water evaporation leaving sand and mud flats and areas of hypersaline water.

“The ecology is crashing,” said Marine Biology teacher and marine microbiology expert Dr Deb Geronimi.

Deb suspects the health of Lake Innes is worse than Lake Cathie’s situation due to the larger surface area exposed to evaporation.

“When Lake Cathie is open to the ocean it’s beautiful and it has continuous seawater flushing twice a day,” Deb said.

“The health of the lake begins with the very smallest microorganisms. They were the first living organisms on this planet and will probably be the last,” she said at the Revive Lake Cathie forum earlier this month.

These microorganisms are struggling to adapt to the constantly changing environment of the lake, and as a result the nutrients are not being recycled, decomposition is slowing and the nitrogen cycle is unbalanced.

“My suggestion would be to keep [Lake Cathie] open all the time and fill Lake Innes back in allowing it to restore to a freshwater lake,” said Dr Deb Geronimi, Marine Biology teacher.

Since the 1960s Council has been forced to artificially open Lake Cathie to the ocean by excavating a channel once the water reached a specific level to avoid flooding local residents.

Lake Innes was once ‘the jewel of Port Macquarie’: the largest freshwater lake in NSW, where Major Archibald Clunes Innes built his mansion along its shores. The grand house overlooked the impressive lake, with a thriving ecosystem that supported the Indigenous Australians and early settlers.

In 1933 the lake was disastrously opened to the saline Lake Cathie in an attempt to drain it, resulting in a complete disruption of the ecosystem that is still attempting to recover today.