|Tracing sewage and natural freshwater input in a Northwest Mediterranean bay: Evidence obtained from isotopic ratios in marine organisms|Lassauque, J.; Lepoint, G.; Thibaut, T.; Francour, P.; Meinesz, A. (2010). Tracing sewage and natural freshwater input in a Northwest Mediterranean bay: Evidence obtained from isotopic ratios in marine organisms. Mar. Pollut. Bull. 60(6): 843-851. dx.doi.org/10.1016/j.marpolbul.2010.01.008
In: Marine Pollution Bulletin. Macmillan: London. ISSN 0025-326X, more
Posidonia oceanica (Linnaeus) Delile, 1813 [WoRMS]; Marine
Sea grass; Mussel caging; Stable isotopes; Sewage; Pollution tracing;
|Authors|| || Top |
- Lassauque, J.
- Lepoint, G., more
- Thibaut, T.
Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves and epiphytes) were harvested from different locations throughout the bay during the touristic summer and rainy seasons. The results from the nitrogen analysis revealed that sewage and harbor outflow promote higher nitrogen levels, enrichment of 15N in the tissues, and a higher seasonal variability in sea grass and epiphytes. In mussel tissues, the d15N was also influenced by sewage and harbor outflow, whereas d13C was influenced by terrestrial inputs. These results suggest that natural and anthropogenic nutrient inputs have a temporary and localized influence and affect the sensitivity of natural isotopic ratios to changes in hydrologic conditions, especially to rain and tourism.