Effects of antibiotics and metals on meiofauna assessed through taxon/functional and modeling tools: a case study of amoxicillin and copper

This research examines the impacts of amoxicillin and copper, separately and together, on the taxonomic and functional diversity of free-living marine nematodes. Sediment samples were gathered from the Jeddah shoreline in Saudi Arabia, and meiobenthic organisms were subjected to two concentrations of amoxicillin [550 and 1100 ng/L] and copper [130 mg/kg dry weight (dw) and 260 mg/kg dw] in microcosms for 30 days. The findings indicated a higher nematode tolerance than that of polychaetes, copepods, isopods, amphipods, and cumaceans. A notable decrease in both nematode species abundance and diversity was observed as contaminant levels rose, resulting in the reduction of sensitive bioindicators, specifically Paracanthonchus sadspitensis, Dorylaimopsis timmi, Cinctonema papillata, Eleutherolaimus obtusicaudatus, Terschellingia longicaudata, Theristus poloris, Halalaimus longicaudatus, Parodontophora breviseta, and Theristus pertenuis for copper, as well as C. papillata, T. longicaudata, H. longicaudatus, T. pertenuis, D. timmi, and Viscosia viscosia for amoxicillin. Conversely, tolerant/opportunistic species such as Metoncholaimus albidus for amoxicillin and Daptonema oxycerca for both copper and amoxicillin showed an increase in abundance. The pairing of amoxicillin and copper demonstrated a synergistic or additive toxic impact. Furthermore, pollution changed the functional characteristics of nematodes, leading to a rise in detritivore species with clavate tails, and a decline in microvore species with conical and filiform tails. A computational analysis also supported these findings by evaluating the toxicokinetics and molecular interactions of amoxicillin and copper.