Exposure to common antidepressants can alter the behavior of crayfish and subsequently affect the ecosystem

Reisinger, AJ, Reisinger, LS, Richmond, EK, and Rosi, EJ. 2021. Exposure to common antidepressants can alter crayfish behavior and affect subsequent ecosystems. Ecosphere 12(6): e03527. 10.1002 / ecs2.3527

Explanation

This study investigated the effects of pharmaceuticals omnipresent in the aquatic environment on ecological processes.

The drugs of interest were selective serotonin reuptake inhibitors (SSRIs), which are also frequently prescribed as antidepressants And this drug has been shown to change the behavior of crayfish. Since crayfish play a central role in freshwater ecosystems, behavioral changes may also affect rivers. In this experiment, we used a 14-day artificial river experiment to expose Rusty Crayfish (Faxonius limosus) to a Y-shaped channel to quantify the effects of SSRI exposure on crayfish behavior and food/same species preferences, and to determine the effects of SSRI exposure on habitat-specific and total river ecosystem function and biomass. We tested the effects of citalopram-crayfish interactions on habitat-specific and total stream ecosystem function and biomass.

Results showed that crayfish exposed to SSRIs showed increased boldness (time to emerge from shelter, P <0.05) and spent more time orienting food resources than crayfish not exposed.

Crayfish increased water column chlorophyll a (P < 0.01) and benthic organic matter (P = 0.03), and in addition crayfish potentially increased water column respiration. (P = 0.09) Potentially nitrate uptake was also reduced (P = 0.05). SSRI exposure increased benthic chlorophyll a (P = 0.07), but there was no significant CRAY + SSRI interaction.

Neither crayfish nor SSRI treatment affected total stream metabolism. These results suggest that citalopram may affect algal biomass, but did not affect ecosystem function. However, the changes in crayfish behavior induced by SSRI exposure could lead to subsequent ecosystem-level effects, as crayfish affected a variety of response indices.

Due to the short duration of the experiment, the effects of the crayfish behavioral changes could not be detected on an ecosystem scale during the study, so further work is needed to quantify the sub-lethal and long-term ecosystem effects of the pharmaceuticals.