Elisa Anna Fano

Impact of Tapes philippinarum farming on nutrient dynamics and benthic respiration in the Sacca di Goro

AbstractThe introduction of the short-necked clam Tapes philippinarum into the Sacca di Goro has over a short period made this coastal environment one of the top European clam production sites. In recent years, this activity has been seriously impacted due to the appearance in the lagoon of large macroalgal beds and the occurrence of dystrophic events causing anoxia and massive deaths of molluscs in the cultivated areas. Tapes cultivation sites now cover more than one third of the lagoon surface at densities sometimes attaining 2000–2500 adult individuals m−2; such densities and the harvesting methods, based on sediment dredging, probably have a strong impact on the benthic system. Whilst a number of studies have reported water–sediment interface induced modifications due to oyster or mussel farming there have been few attempts to quantify how clam farming affects biogeochemical cycles of oxygen and nutrients, in particular in the Sacca di Goro. Two areas, a farmed and a control one, were compared for benthic fluxes and results were correlated with clam biomass. Oxygen, carbon dioxide, ammonium, reactive silica and phosphorus fluxes were stimulated several fold by the presence of Tapes due to the clams, respiration and excretion activities, but also to the reducing conditions in the surface sediments. On average, the whole lagoon dark sediment O2 demand and CO2 production were stimulated by a factor of, respectively, 1.8 and 3.3, whilst nutrient release was 6.5 times higher for NH4+ and 4.6 times higher for PO43-. Our results indicate that clam farmers should carefully consider sustainable densities of Tapes in order to prevent the risk of sediment and water anoxia. Rapid nutrient recycling (up to 4000 μmol NH4+ m−2 h−1 and 150 μmol PO43- m−2 h−1) stimulated by the high biodegradability of clam faeces and pseudofaeces could in turn favour macroalgal growth.

The ecofunctional quality index (EQI): a new tool for assessing lagoonal ecosystem impairment

Abstract A multimetric index for the evaluation of environmental quality (the ecofunctional quality index, EQI) has been developed using biotic data from three Italian coastal lagoons. Sampling programs were conducted between 1998 and 2000, on a yearly basis, with seasonal frequency at diverse sites in each lagoon. The rationale of the index is that certain attributes, selected on the basis of established principles of benthic ecology, are fundamental for lagoon ecosystem function. The chosen attributes were primary productivity, expressed as phytoplankton, seaweed and seagrass biomasses; structure and productivity of the benthic community, expressed as numerical abundance, biomass density, number of species, and taxonomic diversity of macrozoobenthos; and finally, trophic complexity, expressed as macrozoobenthic functional diversity. The EQI is constituted by the sum of weights given to these eight attributes, each transformed onto a dimensionless 0–100 quality scale. In this way, the use of EQI can derive a series of values yielding a ‘functional classification’ of sites within a lagoon or between different lagoons. The proposed index is a low cost, flexible and robust routine indicator of lagoon ecosystem impairment and could be of particular benefit to environmental managers and policymakers who require tools capable of expressing the degree of degradation or environmental quality of different lagoon habitats. The process of developing and the initial testing of EQI reported in this paper is intended as preliminary, and until validation of this index is accomplished by incorporating data from a wider range of lagoon environments, we caution the use of this index in anything other than an exploratory manner.

Decomposition dynamics of the bloom forming macroalga Ulva rigida C. Agardh determined using a 14C-carbon radio-tracer technique.

Abstract The short-term decomposition dynamics of Ulva rigida C. Agardh by a natural bacterial consortium were studied in the laboratory using a 14 C radio-tracer technique. Following an initial rapid loss of approximately 15% of the particulate organic carbon (POC) by leaching of dissolved organic carbon (DOC), there was an exponential loss of POC and an accompanying increase in the labelling of the inorganic carbon (IC) pool. However, losses of labelled POC were significantly greater than the summed accumulation of radiolabel in the IC and DOC pools over the course of the experiments. We propose that this discrepancy may be due to the production of volatile organic compounds (VOC) during decomposition, which were stripped from the medium during the extraction of IC, by acidification and sparging with helium, but were not retained by the KOH traps for IC. The compatible solute dimethylsulphonioproprionate (DMSP) which is accumulated to high concentrations by Ulva spp. and is metabolised by bacteria to volatile dimethylsulphide (DMS) and potentially methane, could be one of the major sources of VOCs during our incubations. Modelled decomposition rates based on the loss of label from the particulate fraction were high, with calculated half times of 8.1 and 7.6 days. However, these rates greatly overestimate true mineralisation rates, since only approximately 50% of the label lost from the POC pool was recovered as IC. Overall these data indicate that previously determined decomposition rates based on loss of dry weight of macroagal biomasses would also greatly overestimate carbon mineralisation rates and hence the oxygen demand for this mineralisation. This aspect may be particularly important for environmental management or modelling of bloom impacted environments, since the most severe impacts of macroalgal blooms are mediated by the hypoxic or anoxic conditions induced when the blooms collapse and hence are strictly related to the oxygen demand for mineralisation of the macroalgal biomasses.

An EPG Study of the Probing Behavior of Adult Bemisia tabaci Biotype Q (Hemiptera: Aleyrodidae) Following Exposure to Cyantraniliprole

ABSTRACT Cyantraniliprole is a novel insecticide for control of multiple chewing and sucking insect pest species including the sweetpotato whitefly Bemisia tabaci (Gennadius), which is one of the most important polyphagous pests in tropical, subtropical, and Mediterranean regions. This study aims to evaluate the effects of cyantraniliprole on the probing behavior of B. tabaci on tomato. Electrical penetration graph data indicated that on plants treated with cyantraniliprole (foliar application), adult whiteflies of the genetic variant Q2 were not able to reach the phloem and consequently did not perform the activities represented by E1 and E2 waveforms, i.e., phloem salivation (during which inoculation of geminiviruses occurs) and phloem sap ingestion (during which geminiviruses are acquired by the whiteflies), respectively. The complete failure of B. tabaci biotype Q adults to feed from the phloem of tomato plants treated with cyantraniliprole could be explained by rapid cessation of ingestion because of the mode of action of this insecticide. Overall, these findings indicated that cyantraniliprole might represent a useful new tool for producers to protect tomato plants from damage by B. tabaci.

An intergrated approach to the assessment of the environmental quality of the Tiber river in the urban area of Rome: A mutagenesis assay (micronucleus test) and an analysis of macrobenthic community structure

Abstract Our aim was to study the environmental pollution of the river Tiber within the urban area of Rome. We studied both the stress of the macrobenthic communities, described by density (calculated as animal biomass) and diversity (calculated with the Shannon index), and the mutagenic effects of waters and sediments, using the micronucleus test in root tips of Vicia faba . Four places (stations) were studied: (1) Castel Giubileo, at the entry of the urban area; (2) Ponte Tor di Quinto, immediately after the confluence of the tributary river Aniene; (3) Ponte Matteotti, at the entry of the historical city center; and (4) Ponte Sublicio, in the middle of the city center. Samples were collected in spring (May, 1989) with an intermediate pollution level, winter (January 1990) with a low one, and late summer (September 1990) with a high one. There is agreement between the environmental damage, measured by diversity of macrobenthic community, and the mutagenic effect of media (water and sediments), identified by micronuclei: while Castel Giubileo shows an acceptable condition in all the seasons, and Ponte Sublicio a bad one, the intermediate stations show a recovery in January.

Impact of commercial clam harvesting on water column and sediment physicochemical characteristics and macrobenthic community structure in a lagoon (Sacca di Goro) of the Po River Delta

The Sacca di Goro is a hypertrophic lagoon of the Po river Delta, which is heavily exploited for rearing ofthe Manila clam, Tapes philippinarum. Harvesting of the clams could add to the general disturbance regime in the lagoon through damage to the benthic community, the release of porewater nutrients which could fuel macroalgal growth and of reduced compounds from the sediment leading to depletion of water column oxygen. We tested these hypotheses during an in situ harvesting experiment. No significant differences were found in population or biomass densities, or community indices between samples collected before and after harvesting. Similarly, no differences were recorded in trophic (food source) availability. Whilst, there was a slight reduction in water column oxygen, pH and Eh values in the plume of suspended sediment, these changes were small. Similarly, increases in water column concentrations of ammonium and reactive phosphorus during harvesting were not significant. Calculations based on profiles of sediment ammonium content, before and after harvesting, demonstrated a release of ammonium equivalent to 13 mmol m−2. In terms of the oxygen and nitrogen budgets of the lagoon the effects of harvesting seem to be of little importance and of the same order of magnitude of sediment-water fluxes driven by clam activity, both terms being subjected to high energy hydrodynarnism.

Occurrence of larval acanthocephalus anguillae (acanthocephala) in the asellus aquaticus (crustacea, isopoda) from the river brenta

Abstract A total of 440 specimens of Asellus aquaticus were collected from the River Brenta (northern Italy) in a single sampling in August 1992, and examined for larval helminth parasites. From the hemocoels of 14 (3.1%) individuals of A. aquaticus, 17 acanthocephalan larvae were removed: of these 15 were well‐developed cystacanths of Acanthocephalus anguillae (a new geographical recording for cystacanth); not more than two larvae were found in a single host. The sex‐ratio among the parasitized isopods was approximately 1:1. In more than 64% of infected A. aquaticus, the integumental pigmentation was darker than that of non‐parasitized individuals. Infected isopods were never observed in amplexus, and one parasitized female specimen carried 50 eggs in its brood pouch. In hosts with well‐developed cystacanths, the displacement of isopod internal organs, such as the alimentary canal, was observed.

Macrofaunal secondary production in a lagoon of the Po River Delta: An evaluation of estimation methods

Abstract The utility of calculating macrobenthic secondary production with estimation methods that have less rigorous data requirements than most classical techniques was investigated at three subtidal sites located in the Sacca di Goro, a brackish lagoon in the Po Delta area (Upper Adriatic Sea). Of the four estimation methods used, two that were based solely on biomass and individual body weight gave the lowest production estimates, while the two that also accounted for population or environmental parameters yield ed higher values. Production estimates ranged from 16.6 to 107.4 g ash free dry weight m‐2 yr‐1 over the period studied. The sec ondary production of the few taxa for which growth and life‐his tory had been formerly estimated in the Po Delta area, was calcu lated by means of a classical technique and compared with fig ures obtained with such empirical models. Average error varied from 13.5% to 75.6%, depending on the method used. Although they may be not preferable to classical techniques, empirical methods can provide a reliable and practical means of estimating secondary production in studies where logistical or economical constraints are operating.

Occurrence of perfluorooctanesulfonate and perfluorooctanoic acid and histopathology in eels from north Italian waters

A perfluorinated alkylated substances (PFAS) biomonitoring study was conducted in European eel (Anguilla anguilla) in Italy for the first time. Perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were assessed in the organs of 35 wild eels from two locations, the highly impacted Po River and the Comacchio Lagoon along the north-western Adriatic coast. PFAS were extracted by ion-pairing liquid extraction procedure and measured using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. There were no significant differences in mean PFAS concentrations (p>0.05) between samples from the two sites. PFOS and PFOA were detectable (>0.4ngg(-1) wet weight, w.w) in 73% and 31% of the total samples, respectively. PFOS concentrations ranged from <0.4 to 6.28ngg(-1)w.w and PFOA from <0.4 to 92.77ngg(-1)w.w. The highest PFAS levels were observed in blood and the lowest in muscle. Histology showed macrophage aggregates and hepatocytic vacuolation in some liver samples. No tissue anomalies were seen in the gonads, suggesting no reproductive impairment. The PFAS contamination levels observed were comparable to, or lower than, those reported in fish in other European countries, seeming to indicate that PFAS pollution of the study area is not remarkable.

Assessment of Insecticide Resistance of Lobesia botrana (Lepidoptera: Tortricidae) in Emilia-Romagna Region

ABSTRACT The European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), is the key pest of vineyard, Vitis vinifera L. In Italy, failures in field chemical pest control have been recently reported. The susceptibility to insecticides indoxacarb, methoxyfenozide, and emamectin benzoate was then evaluated in a L. botrana population collected from a vineyard in Emilia-Romagna (northeastern Italy) where pest management programs achieved unsatisfactory results. The field trial showed that the indoxacarb efficacy toward L. botrana was very low in the two timings of application (7.9 and -1.5%) in comparison with untreated control, while the efficacy of methoxyfenozide (76.1%) and emamectin benzoate (88.8%) was high. The decreased efficacy of indoxacarb was also supported by the results of the laboratory bioassay on neonate L. botrana larvae, in which the resistance ratio was 72-fold in comparison with that of the susceptible strain.