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Photo by Douglas Gayeton


(Nitellopsis obtusa)
This bushy, bright green macro algae features a tiny, white six-pointed-star-shaped "bulbil" on its stems (from which it gets its name). Native to Eurasia, this invasive species was unintentionally introduced into the United States’ Great Lakes in 1978 through the discharge of contaminated cargo ship ballast water. It first appeared in Minnesota's Lake Koronis in 2015.

Organisms that live within inland, estuarine, or marine waters and have been spread to locations where they do not naturally occur, causing economic or environmental harm as well as posing risks to human health. When these new and aggressive species are introduced into an ecosystem, native wildlife may not have evolved defenses to protect against them or compete for resources.

Two opposing rollers working in close proximity to each other mechanically grab and pull starry stonewort onto an incline conveyor which then drops it into a live bottom accumulation bed. It will then be offloaded into trucks and delivered to farms for use as fertilizer.

WHEN STARRY STONEWORT INFESTED LAKE KORONIS, THE RESIDENTS DEVISED A PLAN THAT INCLUDED MECHANICAL PULLERS AND THE APPLICATION OF ALGAECIDES, ALL WHILE KNOWING THAT NEITHER WILL ENTIRELY RID THEM OF THIS AIS. This management strategy focuses on reducing the infestation in shallow parts of the lake (4 to 5 feet) where it presents the greatest nuisance for those using the lake for recreational use. The mechanical puller helps remove some of the weed and thins it out enough for chemical treatments to be more effective. And because starry stonewort is not a vascular plant but instead composed of single cells joined together, each cell must be treated and killed separately, not unlike using a weed killer on a lawn.