INDIVIDUAL AND CUMULATIVE EFFECTS OF FRESHWATER SALINIZATION AND HEATWAVES ON ZOOPLANKTON STRUCTURE AND FUNCTION

Zooplankton play a crucial role in freshwater food webs, linking primary producers and higher trophic levels. However, co-occurrence of stressors may compromise zooplankton ecological functions. Many studies have examined the individual effects of stressors, but few have assessed the cumulative effects of co-stressors on zooplankton community structure and function. We conducted a 6-wk mesocosm experiment to test how crustacean zooplankton community structure and function respond to heatwave (HW) pulses and chloride (Cl^-) press disturbances. We measured structural (biomass, diversity) and functional (respiration) responses. We hypothesized that co-occurring stressors would amplify community disruptions and increase metabolic demand. Community structure showed no individual or interactive effects of either stressor, although diversity increased under the combined stressors. Copepod biomass declined upon the first HW pulse only, suggesting greater resistance upon subsequent HW exposure. Compositional changes suggest a shift toward tolerant taxa under both elevated Cl^- and heatwave treatments. Metabolic responses were similarly limited, with respiration showing no effects of HW, Cl^-, or their interaction, indicating that zooplankton metabolism remained stable despite modest structural change. Overall, HW and Cl^- disturbances resulted in detectable but limited impacts on zooplankton community structure while community function remained comparatively resistant. 

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Adebukola Aborigho, University of Vermont (saseyiadebukola@gmail.com)

Authors:

Adebukola Aborigho, University of Vermont  (saseyiadebukola@gmail.com)

Marie-Pier Hébert, Université du Québec à Trois-Rivières  (mphebert4@gmail.com)

Hannah Cane, University of Vermont  (caneh@newpaltz.edu)

Allie Shiers, University of Vermont  (ashiers135@gmail.com)

Lisette de Senepont Domis, Netherlands Institute of Ecology (NIOO)  (L.deSenerpontDomis@nioo.knaw.nl)

Sven Teurlincx, Netherlands Institute of Ecology (NIOO)  (S.Teurlincx@nioo.knaw.nl)

Jason Stockwell, University of Vermont  (Jason.Stockwell@uvm.edu)