Ricerc@Sapienza

The intensification of agricultural land use and urbanisation has increased nutrient loads in aquatic ecosystems. Nitrogen loads can alter ecosystem structure and functioning, resulting in increased algal productivity, algal blooms and eutrophication. The principal aim of the present paper is to extend the use of epilithic ?15N signatures to a lake ecosystem in order to evaluate the potential impact of anthropogenic nitrogen discharges (organic and inorganic) that can also reach coastal waters.

Effects of two chemical forms of Nitrogen (NH4
+ and NO3
?) on ?15N in Ulva lactuca were analysed separately and
in mixture at two concentrations.We assessedwhether the ?15Nvaluesof U. lactuca discriminate between Nitrogen
from synthetic fertilisers (inorganic) and from fresh cow manure (organic), and the isotopic ability of the
macroalga to reflect Nitrogen concentrations. Isotopic signature and N content of themacroalga reflected different
nitrogenous sources and their concentrations after 48 h. The inorganic Nitrogen source (NH4NO3) altered the

A human-made environmental disaster due to the shipwrecked of Costa Concordia cruise vessel on the Tuscan Island of Giglio (Italy) coast and the possible pollutants release has been feared, so
requiring the activation of removal operations and the monitoring of the marine environment. In the present study, the seagrass Posidonia oceanica (L.) Delile was used as a bioindicator for the impact of the