A further insight into the OM quality features may be provided considering, for the Sturla and Spotorno beaches, the values of the contribution of the
Amprenavir biomass to the OM (sum of proteins, carbohydrates and lipids). We observed higher values on the least-urbanised site and lower on the highly-urbanised beach, indicating a higher trophic limitation for the consumers on the latter. Nevertheless, both values of the autotrophic biomass contribution to the OM were, on average, less than 1%. The data related to the Arenzano beach were higher (up to 2.6%, Covazzi Harriague et al., 2006, may be due to the seasonal period considered), but they were very low if compared to the 16% of Baia Blu beach (Misic and Covazzi Harriague, 2007). The inorganic nutrient inputs coming from stormwater (Peters and Donohue, 2001) and from the sewage effluents (Conley et al., 2009) are able to sustain an active primary production and the biomass accumulation, as probably occurred at Arenzano. However, the higher contents of the degraded
autotrophic pigment observed on our beaches (as shown by the low values of the chlorophyll-a:phaeopigments ratio) indicated conditions adverse to the autotrophic component that were not recorded in the non-urbanised beach of Baia Blu. In addition, we have to keep in mind that the degraded autotrophic material could derive from the torrents and creeks (absent at Baia Blu), thus diluting the autochthonous active pigment concentrations, but unfortunately no information is currently available.
