Weeds fend off algae in Lake Wendouree

COMPETITION has already returned to Lake Wendouree, but it has got nothing to do with boats.The battle is going on mostly under the surface, where algae and lake weeds compete for a share of the nutrients swirling in the re-filling lake's water.So far, the winner is a plant known as water ribbon, which has spread over the lake surface in recent weeks. And for the lake's managers, the Ballarat City Council, it is, for the moment at least, one of the good guys.By taking up nutrients from the water, the plants are preventing the worst case scenario for the lake ? an algal bloom.City of Ballarat sustainability executive officer Ian Rossiter said water ribbon also prevents reduce waves on the lake and provides a habitat for microflora."It's a delicate balance we're treading," Mr Rossiter said. "We've got to err on the side of having as much aquatic plant life in the lake as possible during this initial re-filling phase.""If there is insufficient plant material to do that, we will see a rapid build-up of algal organisms." He said he had met with lake users in the last fortnight and most had agreed it was prudent not to remove weed from the lake at the moment.The council has called for expressions of interest from contractors for the job of harvesting weeds from the lake bed.But Mr Rossiter said cutting weeds would not start until the lake's ecology had settled.The dredging of the rowing course and the on-going re-fill of the lake means that could be as far away as 12 months from now.When that starts, water ribbon is expected to give way to the more common lake weed, water milfoil.Ballarat Yacht Club commodore Brian Canny said in the past the weeds were mostly on the botanic gardens side of the lake.He said while the club wasn't happy about the white ribbon, weeds in the lake were necessary."If there was no weed in the lake at all, it would be a dirty great mudbath," Mr Canny said.