How can interspecific interactions in freshwater benthic macroinvertebrates modify trace element availability from...

Area of Science:

• Aquatic Ecology
• Environmental Chemistry
• Ecotoxicology

Background:

• Bioturbation by benthic macroinvertebrates influences sediment-water solute exchange.
• Trace element (TE) fate in aquatic ecosystems is complex and affected by biological and chemical factors.
• Understanding interspecific interactions is crucial for predicting TE bioavailability and impact.

Purpose of the Study:

• To assess how bioturbation by different freshwater benthic macroinvertebrates affects trace element fate.
• To determine if water TE concentration and animal TE content impair body stores.
• To investigate the role of interspecific interactions in TE bioaccumulation and physiological responses.

Main Methods:

• Exposure of three macroinvertebrate species (amphipods, oligochaetes, bivalves) to TE-contaminated sediment under various single-species and multi-species conditions.
• Measurement of trace elements in water and animal tissues.
• Analysis of animal physiological parameters (protein, triglyceride, energy budget).

Main Results:

• Water TE concentrations increased significantly with 2-3 species, particularly for colloid-associated elements (REE, Cr, U, Pb).
• TE body content in amphipods and mussels increased with the number of coexisting species.
• Amphipod energy budgets improved, while mussel triglyceride levels decreased with increased species interactions.

Conclusions:

• Interspecific interactions are key drivers of TE bioturbation, influenced by TE solubility and colloidal association.
• Species interactions mediate TE exposure and contamination, impacting aquatic invertebrate health and energy budgets.
• Bioturbation and species interactions significantly alter trace element dynamics in freshwater sediments.