title: δ(15)N variation in Ulva lactuca as a proxy for anthropogenic nitrogen inputs in coastal areas of Gulf of Gaeta (Mediterranean Sea).
abstract: We tested the capacity of Ulva lactuca to mark N sources across large marine areas by measuring variation in its δ(15)N at several sites in the Gulf of Gaeta. Comparisons were made with the macroalga Cystoseira amentacea. Variation of δ(15)N values was assessed also in the coastal waters off the Circeo Natural Park, where U. lactuca and C. amentacea were harvested, as these waters are barely influenced by human activities and were used as reference site. A small fragment from each frond was preserved before deployment in order to characterize the initial isotopic values. After 48 h of submersion, U. lactuca was more responsive than C. amentacea to environmental variation and δ(15)N enrichment in the Gulf of Gaeta was observed. The spatial distribution of δ(15)N enrichment indicated that different macro-areas in the Gulf were affected by N inputs from different origins. Comparison of the δ(15)N values of fragments taken from the same transplanted frond avoided bias arising from natural isotopic variability.
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Orlandi
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy.
authors.forename: Flavia
authors.initials: F
authors.lastname: Bentivoglio
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Carlino
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Calizza
authors.affiliation: CNR-IRSA, Water Research Institute, Via Salaria Km 29.300, 00015 Monterotondo, Rome, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Rossi
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy. Electronic address: marialetizia.costantini@uniroma1.it.
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Costantini
authors.affiliation: Sapienza University of Rome, Department of Environmental Biology, Via dei Sardi 70, 00185 Rome, Italy.
authors.forename: Loreto
authors.initials: L
authors.lastname: Rossi
mesh_terms: D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D006802:Human Activities; D006801:Humans; D008522:Mediterranean Sea; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000032:analysis; D044445:Ulva / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009587:Nitrogen Isotopes; D009584:Nitrogen
keywords: Coastal sea; Cystoseira amentacea; Gaeta Gulf; Nitrogen stable isotopes; Pollution; Ulva lactuca