Karsten Rybjerg Larsen highlights alarming changes in water quality at Mariagerfjord in Denmark

For 14 years, Karsten Rybjerg Larsen has been a nature guide in Mariagerfjord. He rows in his kayak twice a week, often rolling over and submerging his head underwater. This year, he remarks that the water has never tasted so bad. “It tastes of murky, rotten water. On a hot summer day, it really tastes awful,” he explains.

Larsen frequently takes school students out on excursions to Mariagerfjord, and they have also noticed changes in the environment. “They think the fjord smells bad. They comment on it, which they haven’t done before,” he adds.

The levels of oxygen depletion in Danish waters are nearly 50 percent higher than they were at the same time last year.