Search results for "composition"

Temporal and spatial variation of the algal community in a southern Mediterranean shallow system

2010

The algal community of a shallow system located in Western Sicily (Mediterranean Sea) has been investigated over 1 year in eight ponds (fredde). The spatio-temporal variation in total algal coverage, species richness and coverage in relation to environmental variables has been analysed. The algal community was very species-poor. A total of 50 taxa, mainly detached algae, were identified. A dominance of filamentous and foliose taxa was observed. Significant spatio-temporal differences in total algal coverage, species richness and coverage between the ponds of group A and those of group B were found. The separation into groups A and B was made a priori on the basis of different levels of prox…

Altered epiphyte community and sea urchin diet in Posidonia oceanica meadows in the vicinity of volcanic CO2 vents

2017

Ocean acidification (OA) predicted for 2100 is expected to shift seagrass epiphyte communities towards the dominance of more tolerant non-calcifying taxa. However, little is known about the indirect effects of such changes on food provision to key seagrass consumers. We found that epiphyte communities of the seagrass Posidonia oceanica in two naturally acidified sites (i.e. north and south sides of a volcanic CO2 vent) and in a control site away from the vent at the Ischia Island (NW Mediterranean Sea) significantly differed in composition and abundance. Such differences involved a higher abundance of non-calcareous crustose brown algae and a decline of calcifying polychaetes in both acidif…

Decomposition rate and invertebrate colonization of seagrass detritus along a hydrodynamic gradient in a Mediterranean coastal basin: The Stagnone di…

2019

International audience; Seagrass leaf litter decomposition is a key component of marine carbon flow driven by both biotic and abiotic factors, including water movement. In this study, we analyse Posidonia oceanica litter decomposition and invertebrate colonization in three sites with different hydrodynamics in a coastal basin. Litterbags were put on the sea bed along a gradient of distance from the open sea, implying a different level of water exchange. Leaf litter mass loss and carbon and nitrogen concentration were analysed, and density and biomass of benthic invertebrates colonizing litterbags were recorded after 3, 7, 14, 47, 101, 152 and 221 days. Results showed that in the most shelte…

Diel feeding habits of juveniles of Mullus surmuletus (Linneo, 1758) in the lagoon of the Stagnone di Marsala (Western Sicily, Italy)

1999

Diet composition, feeding rhythm, gastric evacuation rate and daily ration were investigated in juvenile Mulhis surmuletus (Linneo, 1758). Fish were collected in the lagoon of the Stagnone di Marsala in western Sicily, in July 1995, during a 24 h sampling period. Copepoda, Polychaeta, Amphipoda and Tanaidacea were shown to be the most frequent prey items. The feeding index values showed two different daily feeding times. A unimodal trend in the daily rhythm of food consumption was derived, with a peak in feeding between 1200 and 2000 h. Gastric evacuation in juvenile M. surmuletus is best described by an exponential model, with a gastric evacuation rate R = 0.66 g h-1 (r = 0.88) (T = 24.45 …

Assessment of the ecological status of transitional waters in Sicily (Italy): first characterisation and classification according to a multiparametri…

2010

A 1-year cycle of observations was performed in four Sicilian transitional water systems (Oliveri-Tindari, Cape Peloro, Vendicari and Marsala) to characterise their ecological status. A panel of variables among which trophic and microbial (enzyme activities, abundance of hetetrophic bacteria and of bacterial pollution indicators) parameters, were selected. Particulate organic carbon (POC) and nitrogen (PON) and chlorophyll-. a (Chl-. a) contents defined the trophic state, while microbial hydrolysis rates and abundance gave insights on microbial community efficiency in organic matter transformation and on allochthonous inputs. To classify the trophic state of examined waters, the synthetic t…

Evidences on alterations in skeleton composition and mineralization in a site-attached fish under naturally acidified conditions in a shallow CO2 vent

2021

Abstract Background Ocean acidification may affect fish mineralized structures (i.e. otoliths and skeleton). Methods Here, we compared the elemental composition of muscle and skeleton and the mineral features of skeleton in the site-attached fish Gobius bucchichi naturally exposed to high pCO2/low pH conditions in a shallow CO2 vent with fish of the same species exposed to normal pH. Results Overall, no skeleton malformations were found in both pH conditions, but among-site differences were found in the elemental composition. Interestingly, higher Ca/P values, inducing a moderate skeleton maturation, were found in fish exposed to acidified conditions than in controls. Conclusion Our finding…

Analysis of lipids in pelagic fish of Sicilian Channel and use of fatty acids as bacterial contamination markers

Lipids provide the expendable form of energy in marine ecosystem, and have an important role for the reproductive biology of fish. Also, lipids are important nutrients, versatile markers for marine trophic studies, bacteria markers etc. Among the lipids, several essential fatty acids are determinants for ecosystem health as well as for their known nutritional properties and prevention capacity of chronic diseases. Furan fatty acids (F - acids) are other important lipid bioactive compounds; for these is hypothesized a crucial nutritional role that is synergistic to polyunsaturated fatty acids omega 3 (PUFA ω 3), also if their mechanism is not yet clear. Source of essential fatty acid is the …

Essential Oil Composition of Stems and Fruits of Caralluma europaea N.E.Br. (Apocynaceae)

2010

The essential oil of the stems and fruits of Caralluma europaea (Guss.) N.E.Br. (Apocynaceae) from Lampedusa Island has been obtained by hydrodistillation and its composition analyzed. The analyses allowed the identification and quantification of 74 volatile compounds, of which 16 were aromatic and 58 non-aromatic. Stems and fruits contained 1.4% and 2.7% of aromatic compounds respectively, while non-aromatic were 88.3% and 88.8%. Non-aromatic hydrocarbons were the most abundant compounds in both organs, followed by fatty acids. Data showed differences in the profiles between stems and fruits which shared only eighteen compounds; stems accounted for 38 compounds while fruits for 53. Fruits …

A protocol to evaluate the antioxidant capacity by crocin bleaching assay in Pleurotus edible mushrooms

2008

Unpublished data on the chemical composition and nutritional value of Pleurotus mushrooms, growing on Umbelliferous plants (Apiaceae), are here reported. Cultivated basidiomata of four different Pleurotus taxa were analyzed in order to evaluate the composition in lipids, sugars, nitrogen, water, vitamins, ashes, and energetic values. The results showed that Pleurotus mushrooms are suitable in every type of diet thanks to their low caloric content, gastronomic value, vitamins, and mineral salt contents. The presence of a high content of vitamin B12 and riboflavin in Pleurotus nebrodensis is noteworthy.

Levels of dioxin-like polychlorinated biphenyls (DL-PCBs) and metals in European sea bass from fish farms in Italy

2012

The study evaluated the levels of dioxin-like polychlorinated biphenyls (DL-PCBs) and metals in the fillet of medium (468 ± 92 g) and large (708 ± 135 g) European sea bass (Dicentrarchus labrax) from 11 Italian fish farms using different rearing systems. DL-PCB contamination was higher in fish grown in extensive coastal lagoons compared with intensive inland basins and intensive sea cages (28.5 vs. 9.13 and 13.1 pg Toxic Equivalents (TEQ)/g fat; P < 0.001). Copper concentrations were lower (0.810 vs. 0.993 and 1.071 mg/kg fw) and mercury was higher (0.025 vs. 0.006 and 0.003 mg/kg fw) (P < 0.001) in sea bass from extensive farms than from intensively farmed fish in inland or sea cage system…