Assessment of the ecological status of transitional waters in Sicily (Italy): First characterisation and classification according to a multiparametric approach

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 trophic state index (TRIX) was calculated.Microbial hydrolysis rates correlated positively with POC and Chl-a, which increased along the eutrophication gradient. The significant relationships among TRIX, trophic and microbial parameters suggested the use of leucine aminopeptidase, alkaline phosphatase and POC as suitable parameters to implement the Water Framework Directive when assessing the ecological status of transitional water systems.     

Ecology of Vibrios in the Oliveri-Tindari Lagoon (Messina), Two-Year Study

Abstract. A two-year ecological study in the Oliveri-Tindari (Messina) brackish water ponds evaluated the quantitative and qualitative distribution of Vibrio species in relation to the physicochemical conditions of the ponds.
The evaluation of 204 samples shows a general relationship between the halophilic vibrios and water temperature. In particular this relationship is stronger for the Vibrio fraction able to grow at 37°C, i. e. , those species related to human infections. On the other hand, the halophilic vibrios show no relation with the index of fecal contamination.
The ecology of V. parahaemolyticus is discussed in relation to the salinity of Marinello pond.
The distribution of V. cholerae non O1, isolated from all ponds, shows that this microorganism can be considered as autochthonous in coastal environments.     

Response to short term starvation of growth, haematological, biochemical and non-specific immune parameters in European sea bass (Dicentrarchus labrax) and blackspot sea bream (Pagellus bogaraveo)

Growth, haematological (haematocrit), biochemical (serum cortisol and glucose), and non-specific immune (lysozyme, serum haemolytic and haemagglutinating activities, extracellular respiratory burst activity) parameters, were monitored in European sea bass Dicentrarchus labrax and blackspot sea bream Pagellus bogaraveo subjected to a 31 days starvation compared to fed fish, to assess the responses to feed deprivation of these health status indicators. While haematocrit, serum cortisol, glucose and haemolytic activity of both species did not undergo significant variation following starvation, probably due to the short period applied, some non-specific immune parameters were affected significantly. In the starved sea bass, mucus lysozyme content doubled (1.8 U/mL) compared to the initial value. Haemagglutinating activity was significantly lower in starved sea bass than in fed fish after 31 days. In blackspot sea bream, a slight, not significant, reduction in haemagglutinating activity occurred 11 days after starvation. Respiratory burst activity decreased significantly in the starved fish. In spite of the limited number of examined parameters, the opportunity to use a panel of several indicators to obtain a more complete picture of health status in fish was underlined.     

Observations on the Microbial Biomass in two Stations of Terra Nova Bay (Antarctica) by ATP and LPS Measurements

Abstract. This paper reports on the temporal distribution of microbial biomass, over a I-month survey during austral suinmer 1990. at two sampling stations in Terra Nova Bay (Antarctica) by means of biochemical methodologies such as ATP (adenosine triphosphate) and LPS (lipopolysaccharides). Microbial estimates. derived from ATP measurements. showed an unstable temporal trend and a range characteristic for water with low or. seldom. moderate trophism. Biomass decreased with increasing depth. and photo-autotrophic organisms seem to dominate the whole microbial assemblage. The bacterial population, as derived from LPS determinations, did not show much variability and was well-correlated to other microbiological and chemical parameters. Our data showed that larger mic-roplankters were dominant. but that sometimes pico-sized organisms contributed about 60% to the microbial biomass; this emphasizes the 'still poorly-known' importance of microbes in Antarctic food webs.     

Effect of Hydrocarbons and Decontaminating Substances on Bacterial Flora of Coastal Sediments

Abstract. Seventy six samples of coastal sediments collected in the Straits of Messina were studied in order to evaluate the effects of an oil spill and the consequent "clean-up" operations on heterotrophic acrobic bacteria.
In addition, in vitro tests were carried out to estimate the effects of five dispersants on the growth and oil degrading capacity of marine strains isolated from the same sediments.