Influence of large-spectrum environmental contamination on the micro–meiobenthic assemblages in harbour sediments of the ligurian sea (W Mediterranean)

The concentration of a large spectrum of environmental contaminants (PCBs, PAHs, pesticides and metals) was assessed in surface sediments of two Ligurian harbours (Sanremo and Alassio, NW Mediterranean Sea, Italy) and their relative impact on micro–meiobenthic assemblages was analysed. Concentration, distribution and relative importance of the different contaminants varied considerably between harbours in relation to the different anthropic activities and contamination sources. Results from Principal Component Analysis indicated that high levels of contaminants were typically correlated with low micro–meiobenthic abundance in the sediment. Heavy metals and the organic enrichment were the main factors affecting the distribution and abundance of the bacterial and meiofaunal assemblages in Alassio harbour, whereas hydrocarbons and pesticides played a major role in Sanremo sediments. Neither the bacteria density nor the meiofauna abundance were dependent on sediment grain size, suggesting that micro–meiobenthic parameters may be under the influence of other variables. Our results suggest that high concentrations of contaminants independently from their source or typology are responsible for the impact observed on micro–meiobenthic assemblages in these harbours.     

Sediment organic matter and meiofauna community response to long-term fish-farm impact in the Ligurian Sea (Western Mediterranean)

Quantitative and qualitative changes in meiofauna community structure were investigated to assess the impact of a fish farm, which was operating continuously for 15 years (La Spezia Gulf, W Mediterranean). Sediment samples were collected in June, July, September, October 2000 and February 2001 for the analysis of phytopigments (chlorophyll-a and phaeopigments), the biochemical composition of organic matter (proteins, carbohydrates and lipids) and related to meiofaunal parameters.

Sediment organic matter reached extremely high concentrations beneath the fish cages when compared to the control. Particularly lipids, carbohydrates and chlorophyll-a were significantly higher in fish-farm sediments. On a long-term basis meiofauna displayed adaptations in sediments beneath the cages resulting in an increase of density. Organic impact on meiofaunal community structure was evident in terms of an increase of the nematodes to copepods (Ne/Co) and nauplius to copepods (Na/Co) ratios in fish farm sediments. Cumaceans and kinorhynchs were encountered in control sediments, but disappeared in fish-farm samples. These data suggest that meiofauna is a sensitive tool for evaluating the effects of organic enrichment in fish farm impacted areas.     

Cosmogenic exposure dating constraints for coastal landslide evolution on the Island of Malta (Mediterranean Sea)

Landslides affecting the north-western coast of the Island of Malta have been investigated and monitored for 10 years. As a result of a bathymetric survey, it was discovered the deposits continued out onto the seafloor, thus raising questions as to the timing of their development. Furthermore it was uncertain as to which environment they developed in and which factors controlled their movements. The aim of this paper is to investigate representative detachments to chronologically constrain these mass movement events and outline their spatial and temporal evolution. Samples for exposure dating using the cosmogenic nuclide ³⁶Cl were collected from head scarps and blocks located within two long-term monitored landslides characterised by extensive block slides. The results indicate the oldest dated block detachment occurring in a subaerial environment at ca. 21 ka, when the sea level was about 130 m lower than at present. Mass movement possibly accelerated when sea level reached the landslide toe during the post-glacial marine transgression. Considering the timing of block movement, the landslide deposits observed today appear to be related to a first-time failure involving a large part of the slope, though and alternative hypothesis is also taken here into account. This main event is likely to have been followed by secondary movements influenced by toe undercutting and clay saturation due to rising sea level. However, further research on mass movement kinematics is required in order to model their evolution and explore whether this interpretation is widely applicable along the Maltese coast.     

A Functional Approach to the Assessment of the Nutritional Value of Particulate Organic Matter

Organic matter lability can be determined with different approaches, based on the quantitative and qualitative estimate of its nutritional value. the C/N ratio and the particulate organic matter (as the sum of protein, carbohydrate and lipid bulks) vs total suspended matter (POM/TSM) deal with a quantitative assessment of the organic matter bulk, while other indices such as proteins/carbohydrates ratio (PRT/CHO) may give also qualitative information. Gordon (1970) proposed a functional approach, based on organic carbon decrease after enzymatic digestion. Coupling Gordon's approach with the evaluation of the main biochemical components (proteins, carbohydrates and lipids) contained in the particulate organic matter, a simple method to assess lability and nutritional value of organic substrates is proposed.

Water samples were collected at the surface and close to the bottom in a shallow coastal station (10 m depth) in the Marconi Gulf (Ligurian Sea, NW Mediterranean). the difference between “total labile” and “hydrolyzed labile” organic matter (respectively before and after enzymatic digestion) suggests a relevant presence of resuspended refractory materials vs about 60% of labile hydrolyzed organic matter, thus confirming the importance of a more qualitative approach to organic matter studies.     

Farmer knowledge and a priori risk analysis: pre-release evaluation of genetically modified Roundup Ready wheat across the Canadian prairies

Background, aim, and scope  

The controversy over the world’s first genetically modified (GM) wheat, Roundup Ready wheat (RRW), challenged the efficacy of ‘science-based’ risk assessment, largely because it excluded the public, particularly farmers, from meaningful input. Risk analysis, in contrast, is broader in orientation as it incorporates scientific data as well as socioeconomic, ethical, and legal concerns, and considers expert and lay input in decision-making. Local knowledge (LK) of farmers is experience-based and represents a rich and reliable source of information regarding the impacts associated with agricultural technology, thereby complementing the scientific data normally used in risk assessment. The overall goal of this study was to explore the role of farmer LK in the a priori risk analysis of RRW.     

Benthic-pelagic coupling in frontal system areas of the Northern Adriatic Sea: Analysis of the carbon budgets

Sediment samples were collected between 1996 and 1998 during 4 cruises in the northern sector of the Adriatic Sea, facing the Po River outflow. In each sampling period, after identification of the front line, a grid of 6 sampling stations was selected in order to cover: the coastal area (largely affected by river waters), the inner and outer front areas, and the offshore waters. The biochemical composition of sedimentary organic matter (OM, lipids, proteins, carbohydrates and photosynthetic pigments) and enzymatic activity rates were studied to provide information on the potential organic matter turnover. Tentative estimates of the organic carbon budgets (input/production versus requirement by benthic consumers) are presented. Benthic carbon requirements, estimated from bacterial plus meiofaunal secondary production, was high (897 r mg r C r m m 2 r d m 1 ). OM concentrations in the Northern and Middle Adriatic Sea displayed high values, proteins being dominant, thus suggesting inputs of freshly produced material to the sea floor. OM turnover was generally rapid (11-30 r d m 1 ) and higher during summer. The uncoupled enzymatic rates ( i.e. faster protein than carbohydrate mobilisation in February, 1997) determined a decrease of the OM quality that plays an important role in biogeochemical cycles and OM diagenesis, limiting bacterial secondary production and sedimentary organic carbon utilisation. These data suggest that the efficiency of the system in the transfer of energy through the food web is generally higher in summer, especially during mucilage production.     

Effects of repeated fumonisin B1 exposure on markers of oxidative stress in liver,kidneys, and lungs of C57BL/6 mice

Abstract

Fu monisin B₁ (FB₁) is a mycotoxin commonly found in maize and maize-based products. Ingestion of FB₁-contaminated causes a myriad of dose- and species-dependent toxic effects to human and animal health. In the present study we evaluated the effects of FB₁ (8?mg/kg, i.p. for 4?days) on body weight and oxidative stress parameters in the liver, kidney and lung of C57BL/6 male mice. No changes in the organ-to-body weight ratio, organ-to-adrenal gland weight ratio or organ-to-brain weight ratio were found. On the other hand, FB₁ exposure increased NPSH levels in liver and lungs whereas decreased FRAP content in liver and kidneys. Levels of TBARS, ascorbic acid and NOx content were not altered by FB₁. In summary, four days of FB₁ exposure are sufficient to disrupt antioxidant defenses in liver, kidneys and lungs of C57BL/6 male mice without concomitant changes in organs weight.     

A Pathological Late Pleistocene canid from San Sidero (Italy): implications for social- and feeding-behaviour

Evidence of diseases on vertebrate fossil bones can provide detailed information on many aspects of extinct animals. This study focused on pathological craniodental remains (left maxilla and dentary) referred to the canid Cuon alpinus unearthed from a Late Pleistocene karst filling deposit at San Sidero (Apulia, southern Italy). These fossils show clear evidence of a chronic periodontitis that caused the animal’s death. Clinical diagnosis of the disease and the timing of its development have been defined on the basis of a veterinary odontostomatology approach, in addition to radiographic and tomographic techniques. From the initiation of the infection until death, a time span of at least 6 months occurred, and three main steps have been defined: (1) the bacterial infections of the buccal cavity turning into severe periodontitis, (2) the fracture of the lower carnassial and (3) the loss of teeth due to the worsening infection that deformed and/or eroded maxillary and mandibular bones and enlarged alveoli. The analysis of the palaeopathology also provides information about the biomechanics of the bite, on the feeding behaviour and on the relationships of injured members in a pack of Late Pleistocene canids.