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  • Writer's pictureSofia Manouki

IT’S ALIVE!: Bright green stuff takes over Groningen canals

Updated: Nov 13, 2020

Huge duckweed carpets appear in Groningen canals and become a nuisance for sailors and boat owners, after rise in water temperature leads to a rapid growth of the invasive species.

A thick, bright green, algae-like substance can be seen floating atop Groningen’s canals these days, causing a headache for houseboat owners and recreational sailors who find themselves unable to use their vessels as sunny, warm days continue.

Duckweed, a type of flowering aquatic plant that floats on the surface of still or slow-moving bodies of fresh water, proliferates greatly when there is hot weather and low water flow.

As sunny and warm days in Groningen follow one another uninterruptedly on the dusk of the third hot summer in a row, duckweed rapidly doubles its biomass in the canals, since it is left unrestricted.

As a result, boat owners in Groningen struggle with clogged propellers and, in the case of houseboats which are not connected to the town’s sewer system, dysfunctional toilets. These problems have lead to a major decrease in sailing, even in the renowned sailing spots of nearby Assen.

An anonymous source working for the Environmental Department of the municipality of Groningen, comments that “there’s not a lot we can do about it”, but “we just have to wait until it gets cooler”, as duckweed beds will naturally disperse then.

Leaving aside the municipality’s somewhat carefree approach when it comes to frustrated humans, duckweed is, at least, not a nuisance for ducks and geese who readily consume it.

In the end, to onlookers and sailors alike, the strikingly bright green carpet of duckweed and its sabotaging effects, might serve as a much-needed reminder of climate change, as the debate for global warming keeps getting side-tracked by sceptics these days.


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