Assessing the ecological status of the North-western Adriatic Sea within the European Water Framework Directive: a comparison of Bentix, AMBI and M-AMBI methods     

Roberto Simonini  Valentina Grandi  Gloria Massamba-N'Siala  Mirko Iotti  Giuseppe Montanari  & Daniela Prevedelli 《Marine Ecology》2009,30(2):241-254

In this paper we looked for the most suitable method for benthic ecological quality status (EcoQS) assessment of the North-western Adriatic Sea. Taking into account the historical and present information, we inter-compared our expectations in terms of EcoQS, with the Bentix, AMBI and M-AMBI classification metrics results, and investigated the sensitivity of these indices to the spatial, seasonal and inter-annual variability of benthic communities. The sampling sites were located at increasing distances with respect to the Po River mouth, along an (inverse) gradient of eutrophication. Moreover, a 2-year monthly monitoring plan (October 2004–September 2006) was carried out at the CEBEB site, located in a central position with respect to the investigated area. The results highlighted that the three indices differed in the sensitivity to spatial and temporal variability of the benthic communities. The strong seasonal and inter-annual changes in the benthic communities had a significant effect on the Bentix, whereas no relevant modifications were observed on the EcoQS assignation obtained using the M-AMBI and AMBI methods. The environmental quality ratios (EQR) values and EcoQS classification obtained by the Bentix and AMBI did not match expectations, as they were not inversely correlated with the site distances with respect to the Po mouth, whereas the M-AMBI clearly discriminated the most and the least eutrophicated sites. It thus appears that the M-AMBI could be considered to be the most valuable method for the ecological-status assessment of the North-western Adriatic Sea benthic ecosystem.  相似文献   

Responses of a Northern Adriatic Ampelisca-Corbula community to seasonality and short-term hydrological changes in the Po river     

N'siala GM  Grandi V  Iotti M  Montanari G  Prevedelli D  Simonini R 《Marine environmental research》2008,66(4):466-476

During the 20th century, increased nutrient inflow has increased the frequency and intensity of eutrophication events in the North-western Adriatic Sea. More recently, evidence of a reduction in the Po river flow and a recovery of the benthic environment were reported. We examined the role played by Po river regime and seasonality in determining the temporal pattern of macrozoobenthos variation: samples were collected from a site located 10-12km off Cesenatico during two years from October 2004 to September 2006, when the mean Po discharge remained exceptionally low. 88 taxa were found, and the community was dominated by few species: Ampelisca diadema, Lumbrineris latreillii, Corbula gibba, Aricidea claudiae, Levinsenia gracilis and Nucula nucleus account for about 80% of total abundances. The density of these species exhibited a marked seasonal variability. Moreover, the total abundance and the density of the sensitive species, A. diadema, were negatively affected by several disturbance events (hypoxic conditions, frequent storms and an anomalous winter flood) that occurred between November 2005 and March 2006. The reduction of C. gibba and the increase of A. diadema densities observed in the investigated period, and verified recently by other authors could be related to the reduction in river inputs as a consequence of climatic changes.  相似文献   

Organic waste impact of capture-based Atlantic bluefin tuna aquaculture at an exposed site in the Mediterranean Sea     

Luigi Vezzulli  Mariapaola Moreno  Valentina Marin  Elisabetta Pezzati  Marco Bartoli  Mauro Fabiano 《Estuarine, Coastal and Shelf Science》2008

A variety of pelagic and benthic parameters were measured at an aquaculture farm used for the fattening of Atlantic bluefin tuna (Thunnus thynnus) which is located at an exposed site (700 m from the coast, average bottom depth of 45 m and average current speed of 6 cm s⁻¹) in the Mediterranean Sea. The objective was to test whether modern off-shore tuna fattening industries can exert a sustainable organic waste impact on the receiving environment as has been reported for the offshore culture of more traditional Mediterranean species such as sparids. In the water column, the concentration of phytopigments, organic matter, heterotrophic bacteria and the taxonomic abundance of mesozooplankton (at the species level) were assessed. In the sediment, we assessed the concentration of reduced sulphur pools, phytopigments, organic matter, heterotrophic bacteria and the taxonomic abundance of meiofauna (at the taxa level) and nematodes (at the genus level). For most parameters, we found no substantial differences between farm and control sites. Deviations of farm values from control values, when they occurred, were small and did not indicate any significant impact on either the pelagic and benthic environment. Deviations were more apparent in the benthic compartment where lower redox potential values, higher bacterial production rates and a change in nematode genus composition pointed out to early changes in the sediment's metabolism. In addition, indigenous potential pathogenic bacteria showed higher concentration at the fish farm stations and were a warning of an undesirable event that may become established following aquaculture practice in oligotrophic environments. The overall data from this study provide extensive experimental evidence to support the sustainability of modern offshore farming technology in minimizing the hypertrophic-dystrophic risks associated with the rapidly-expanding tuna-fattening industry in the Mediterranean Sea.  相似文献   

A piecewise curve-fitting technique for vertical oceanographic profiles and its application to density distribution     

Viacheslav G. Makarov  Oleg V. Zaytsev  Valentina D. Budaeva  Felipe Salinas-Gonzalez 《Journal of Oceanography》2008,64(5):675-690

A unified method of approximation, extrapolation, and objective layering is offered for processing vertical oceanographic profiles. The method is demonstrated using seawater density and consists of adjustable splitting of each individual profile into N vertical layers based on tentative, piecewise linear homogeneous approximation with specified accuracy and a final fitting of an N-layered analytical model to data. A set of 3N coefficients of the model includes one density value at the sea surface; N−1 depths of layer interfaces; and N pairs of coefficients that describe a profile shape within the n-th layer—an asymptotic density value (a key parameter for extrapolation) and a vertical scale of maximum density variability (related to vertical gradient). Several distinctive characteristics of the technique are: (1) It can be used for the analysis of the vertical structure of individual profiles when N is an unknown parameter, and spatial interpolation when N should be equal for all profiles. (2) A justified downward extrapolation of incomplete data is possible with the model, especially if historical deepwater profiles are available. (3) Layer interfaces, as well as other coefficients, are derived with only one fitting to the entire profile. (4) The technique, using its general formulation, can serve as a parent for developing various types of models. The simpler step-like (with hyperbolic or exponential approximation) and more complicated smooth (continuous in gradient space) models were designed and tested against a large number of density profiles from the Sea of Okhotsk and the Gulf of California. Comparison of parametric, z-levels and isopycnal averaging was done for the region off the northeastern coast of Sakhalin.  相似文献   

Evaluation of DNA Damage in the Marine Mussel Crenomytilus grayanus as a Genotoxic Biomarker of Pollution     

SLOBODSKOVA Valentina V.  ZHURAVEL Elena V.  KUKLA Sergey P.  CHELOMIN Victor P. 《中国海洋大学学报(英文版)》2019,(1):159-164

Marine pollution affects all life processes in aquatic organisms. The genotoxic effect of pollution on the mussel Crenomytilus grayanus was assessed. Bivalves were collected from the ‘clean'(Vostochnaya Cove) and polluted(Nakhodka Bay) areas in the Peter the Great Bay. The degree of DNA damage in C. grayanus was determined by alkaline comet assay as mean percentage of DNA in tail, and the genetic damage index was calculated. Our results indicate that almost one-third of DNA in cells of gills and digestive gland of C. grayanus inhabiting the Nakhodka Bay had destructive changes compared to the individuals of this species from the Vostochnaya Cove. This study has shown that chronic pollution of the aquatic environment causes destructive changes to DNA in gill and digestive gland cells of C. grayanus.  相似文献   

Validation of Geant4 10.3 simulation of proton interaction for space radiation effects     

Vladimir Ivanchenko  Paolo Dondero  Valentina Fioretti  Anton Ivantchenko  Fan Lei  Simone Lotti  Alfonso Mantero  Teresa Mineo 《Experimental Astronomy》2017,44(3):437-450

Monte Carlo simulation of space radiation effects induced by protons is important for design of space missions. Geant4 is a well established toolkit for Monte Carlo simulation focused on high energy physics applications. In this work, a set of new validation results versus data for Geant4 electromagnetic and hadronic interaction of protons is presented and discussed. Optimal configuration of Geant4 physics for space applications is proposed.  相似文献   

New data on earthquake focal mechanisms in the Laptev Sea region of the Arctic-Asian seismic belt     

Alena I. Seredkina  Valentina I. Melnikova 《Journal of Seismology》2018,22(5):1211-1224

We consider 16 earthquakes with M_w?=?4.2–5.2 that occurred in the south-eastern part of the Laptev Sea shelf, Lena River Delta, and North Verkhoyanye (Russia) in 1990–2014. Focal mechanisms, scalar seismic moments, moment magnitudes, and hypocentral depths of the seismic events have been calculated from the data on amplitude spectra of surface waves and P wave first-motion polarities. The obtained results sufficiently implement the existing dataset on reliable earthquake source parameters for the study region and prove the change of the stress-strain state of the crust from extension on the Laptev Sea shelf to compression on the continent providing finer spatial details of the deformation field in the transition zones such as Buor-Khaya Bay and the Lena River Delta.  相似文献