The need to protect our freshwater lakes will see researchers go to depths they have never probed before.
The Otago Regional Council is extending a trial using technology to monitor the effects of climate change and human activity on lakes in the area.
On the surface, our lakes are scenic gems across the Queenstown-Lakes District, including Lake Wakatipu, Lake Wānaka and Lake Hayes.
But underneath it could be a different picture.
“Although we’ve been there for 20 years measuring several different parameters in those lakes, they are still poorly understood,” the council’s lakes scientist Hugo Borges said.
“We need to know more.”
The council’s since installed scientific buoys which send back continuous data through a power-generated capsule of sensors which scans the lake.
Each high tech buoy costs around $100,000.
A trial of one scientific buoy has been underway at Lake Hayes since 2019.
Nick Boyens, the environmental monitoring network lead at the council, said a team would “go out on the lake and take manual samples and do a manual profile” once a month.
“Now we’ve made a buoy that’s taking a profile six times a day, so we’re getting a lot more data and we can see fluctuations over time a lot easier.”
The capsule, which is attached to the buoy, goes down around 30 meters deep into Lake Hayes.
The sensors measure things including temperature, algae growth and oxygen levels.
The data is then sent directly to scientists back at the base to fully understand the lake conditions.
“We can better manage and adjust our program to capture any influence from pollution or climate change, and the data will produce further modeling for the lake,” Borges said.
Some of the region’s deepest lakes – Lake Wakatipu, followed by Lake Wspider – are up next but it’s a mammoth task.
Borges called the lakes “very unique”.
“They are very important to understand the mixing processes of the lake and how this is influencing the nutrients’ circulation in the lake.”
The equipment will reach down 10 times deeper than the previous trial.
For comparison, the Southern Hemisphere’s tallest freestanding structure, Auckland’s Sky Tower, stands at around 330m.
But the scientific buoy in Lake Wakatipu will be examined even further than that – down to 375m.
“If we start monitoring now, we can track changes going forward,” Boyens said.
“If it does start to change, we can be onto it and try and work it out sooner before it becomes too late.”
“We know that the world is facing many changes; there’s a lot of talk about climate change,” Borges added.
“Those buoys will have a great addition for data understanding.”
.