Antidepressant Pollution Alters Crayfish Behavior, With Impacts to Stream Ecosystems

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Pharmaceutical pollution is found in streams and rivers globally, but little is known about its effects on animals and ecosystems. 

Pharmaceutical pollution is found in streams and rivers globally, but little is known about its effects on animals and ecosystems. A new study, published in the journal Ecosphere, investigated the effects of antidepressant pollution on crayfish. Just two weeks of citalopram exposure caused changes in crayfish behavior, with the potential to disrupt stream ecosystem processes like nutrient cycling, oxygen levels, and algal growth. 

Coauthor Emma Rosi, a freshwater ecologist at Cary Institute of Ecosystem Studies, says, “Animals living in streams and rivers are exposed to a chronic mix of pharmaceutical pollution as a result of wastewater contamination. Our study explored how antidepressant levels commonly found in streams impact crayfish, and how these changes reverberate through stream ecosystems.”

Crayfish are a keystone species in streams, where they eat invertebrates, break down leaf litter, and cycle nutrients. They are stress-tolerant and can become abundant in urban waterways. These freshwaters are prone to receiving pharmaceutical pollution from sewer overflows, leaky septic tanks, and treated wastewater effluent that contains pharmaceuticals.

Lead author Alexander Reisinger, an Assistant Professor at University of Florida, Gainesville, says, “Previous research via direct injection found that antidepressants alter serotonin and aggression in crustaceans. Our study found that exposure to low doses of citalopram – at levels currently found in urban streams as a result of pollution – is enough to alter crayfish behaviors like foraging, aggression, and shelter use.”

Read more at Cary Institute of Ecosystem Studies

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