The effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern Mediterranean coastal area.
Stable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations: "Impact" and two putative "Controls" sited to the north of the impacted location. While delta(13)C values of both organic matter sources and consumers varied little between locations, delta(15)N spatial variability was higher and delta(15)N was shown to be a good descriptor of organic enrichment and uptake of anthropogenically derived material within coastal food webs. Isotopic data were analysed using a multivariate approach. Organic matter sources and benthic components were more sensitive to pollution than nektobenthic species and revealed that the effects of anthropogenic activities seem to be detectable over a wide area. The study site is characterised by wide waste dispersal, which brings a reduction in impact in the area directly affected by organic matter inputs and enlarges the area of moderate impact.
Laboratorio di Biologia e Risorse Marine, Dipartimento di Biologia Animale, Università di Palermo, Via Archirafi, 18-90123 Palermo, Italy. vizzini@unipa.it
Salvatrice
S
Vizzini
Antonio
A
Mazzola
D035961:Alismatales; D000818:Animals; D017756:Aquaculture; D002247:Carbon Isotopes / Q000032:analysis*; D000460:Chlorophyta; D004784:Environmental Monitoring; D005399:Fishes; D020387:Food Chain; D009587:Nitrogen Isotopes / Q000032:analysis*; D049833:Sepia; D012722:Sewage; D012802:Sicily
D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D012722:Sewage