Trophic restructuring (Wieser 1953) of free-living nematode in marine sediment experimentally enriched to increasing doses of pharmaceutical penicillin G

Abstract

Trophic structure of free living nematode from Bizerte lagoon was tested by a microcosmic study after 30 days of exposure with 5 increasing doses of pharmaceutical penicillin G (D1: 3 mg L(-1), D2: 30 mg L(-1), D3: 300 mg L(-1), D4: 600 mg L(-1), D5: 700 mg L(-1)). Results showed significant differences between nematode assemblages from undisturbed controls and those from penicillin G treatments. Selective deposit-feeders (1A) or nonselective deposit-feeders (1B), very abundant in the control microcosm, were significantly affected and their dominance declined significantly. Epistrate feeders (2A) were significantly gradual increase for all microcosms treated with penicillin G, appeared to be more tolerant to the antibiotic and to take advantage of the growing scarcity of other trophic groups. Compared to the control microcosms, omnivorous-carnivorous (2B) was found to be higher in all treated microcosms, with the exception of those treated with D5. Trophic index (Σθ(2)) was significantly reduced in all microcosms treated whereas trophic ratio 1B/2A appears to be insignificant.

Effect of oxytetracycline on the community structure of nematodes: results from microcosm experiments

“…In the third experiment, the density of the nematodes in the high concentration microcosms (100 ppm and 200 ppm) was higher than the low concentration (control, 0.5 ppm, and 1 ppm). According to a study by Nasri et al (2015Nasri et al ( , 2016, the nematode density of some microcosms treated with penicillin G increased, and the antibiotics had a strong effect on the trophic structure and group composition of nematode communities. In particular, out of the nematode species that increased in this study, Daptonema spp.…”

Marine Free-Living Nematodes as Tools for Environmental Pollution Assessment: A Special Focus on Emerging Contaminants Impact in the Tunisian Lagoon Ecosystems

“…Epistrate Feeders (EF) seem unaffected by the treatment but an abundance of optional Predators (FP) and exclusive Predators (Pr) showed a significant increase in dominance compared to the control [54]. In addition, the trophic index was significantly reduced in all microcosms treated whereas the trophic ratio 1B/2A appears to be insignificant [55].…”

New Approach for the Evaluation of Ecological Quality in the Mediterranean Coastal Ecosystems, Case Study of Bizerte Lagoon: Marine Nematodes Functional Traits Assessment

“…Thereby, free marine nematodes are considered a useful tool to assess the presence of impact in marine ecosystems since they spent their life in the benthic ecosystems inhabiting the first ten centimeters of marine sediments [9] therefore directly exposed to pollutants. Nematodes are ubiquitous (the abundance ranges from 11 to 24 million individuals per square meter), occupy a key role in the benthic food webs [10], play an important role in the ecosystems functioning [11] through sediment aeration [12], and the mineralization of organic matter [13]. Additionally, due to their short life cycles, rapid metabolic rates, benthic larval stages, and rapid responses to environmental changes, nematodes are considered an ideal model for laboratory experiments [14,15], and are classified excellent indicators for biomonitoring activities [9].…”