Relevance of wound-activated compounds produced by diatoms as toxins and infochemicals for benthic invertebrates

Plants evolve the production of wound-activated compounds (WACs) to reduce grazing pressure. In addition, several plant-produced WACs are recognized by various invertebrates, playing the role of infochemicals. Due to co-evolutionary processes, some invertebrates recognize plant infochemicals and use them to identify possible prey, detect the presence of predators or identify algae containing various classes of toxic metabolites. Different metabolites present in the same algae can play the role of toxins, infochemicals or both simultaneously. We investigated the infochemical activity of compounds extracted from three diatoms epiphytes of the seagrass Posidonia oceanica, by conducting choice experiments on invertebrates living in the same community or in close proximity. Furthermore, the specific toxicity of the extracts obtained from the same algae was tested on sea urchin embryos using a standard bioassay procedure, to detect the presence of toxins. The comparison of the two effects demonstrated that invertebrates are subjected to diatom wound-activated toxicants when these algae are not associated with their own habitat, but they are able to recognize volatile infochemicals derived from diatoms associated with their habitats. The specific toxicity of WACs was shown to be inversely correlated to the perceptive ability of invertebrates towards volatile compounds liberated by the same algae. Hence, when the recognition of specific algae by a given invertebrate species evolves, their detrimental effects on the receiving organism may be lost.     

Differences in olfactory species recognition in the females of two Australian songbird species

Although birds have recently been shown to possess olfactory abilities and to use chemical cues in communication, limited effort has been made to demonstrate the use of odorants in social contexts. Even less is known regarding the use of odorants in species recognition. The ability to recognize conspecifics should be more pronounced in social species. This study investigated the importance of olfactory cues in species recognition in females of two estrildid finch species with different levels of sociality. Combining odor preference tests with chemical analyses, we surveyed whether female zebra finches and diamond firetails are able to distinguish between the species based on volatile traits and whether individuals exhibit species-specific differences in body odorants. Zebra finches are more social than diamond firetails; nevertheless, both species have an overlapping distribution area. Applying an experimental Y-maze paradigm, we showed that zebra finches can use differences in their species odor fingerprints and displayed a significant preference for the odor of conspecifics over that of heterospecifics, whereas diamond firetails did not reveal a preference. Using gas chromatography and mass spectrometry, we demonstrated that body odorants of the two species were significantly different in relative composition. This finding demonstrates the potential importance of olfactory cues in species recognition, at least in social bird species. Even these two closely related species displayed remarkable differences in their responsiveness to similar chemical cues, which might be caused by species-specific differences in ecology, physiology, or evolution.     

Males are faster foragers than females: intersexual differences of foraging behaviour in the Apennine chamois

Availability of food resources and individual characteristics can influence foraging behaviour, which can differ between males and females, leading to different patterns of food/habitat selection. In dimorphic species, females are usually more selective in food choice, show greater bite rates and spend more time foraging than males. We evaluated sexual differences in foraging behaviour in Apennine chamois Rupicapra pyrenaica ornata, during the warm season, before the rut. Both sexes selected nutritious vegetation patches and spent a comparable amount of time feeding. However, males had a significantly greater feeding intensity (bite rate) and a lower search effort for feeding (step rate), as well as they spent more time lying down than females. Females selected foraging sites closer to refuge areas than males. In chamois, sexual size dimorphism is seasonal, being negligible in winter–spring, but increasing to 30–40 % in autumn. Our results suggest that males enhance their energy and mass gain by increasing their food intake rate during the warm season, to face the costs of the mating season (November). Conversely, females seem to prioritize a fine-scale selection of vegetation and the protection of offspring. A great food intake rate of males in the warm season could have developed as a behavioural adaptation leading herbivores to the evolutionary transition from year-round monomorphism to permanent dimorphism, through seasonal dimorphism.     

Where is the best site for wave energy exploitation? Case study along the coast of northern Latium (ITALY)

The present work proposes a siting process for the detection of a suitable site for wave energy exploitation. The choice of a suitable site is based on the good agreement between energy availability, environmental sustainability, and equipped facilities to exploit wave energy. The case study in the northern Latium coast is explicative because in this area there are several activities that affect marine ecosystems, and the introduction of renewable energies promote the reduction of anthropic pressures. The nearshore wave power is studied through the numerical wave model (CMS-Wave), and available wave buoys along the coast were used to compare numerical results. In correspondence with Civitavecchia harbour, the largest nearshore wave energy was found; the large depth in front of the breakwater allows to conserve a great part of offshore wave power, with an average dissipation rate of 10 % less than offshore, with mean annual available wave energy of 25.4 MWh/m and seasonal fluctuation of 5.4 MWh/m. This area appears to be an optimal site for nearshore and shoreline wave energy device tests and installations, for energy availability (intermediate level respect Mediterreanean Sea), low potential environmental impact, easier accessibility, and policy oriented towards a larger sustainability of harbour activities.     

EU vision of sustainable agriculture,land use,forestry and management of natural resources – level of the Slovak state administration convergence to the EU requirements

The EU vision of sustainable agriculture, land use, forestry and management of natural resources contributes to the balanced exploitation of the environment, taking into account rural development strategy. Whilst the EU directs activities through legislative tools, national systems of public administration are responsible for the implementation of the respective laws. Despite there not being acquis communautaire in public administration, non-formal cooperation has nevertheless emerged and systems of national public administration have to meet EU criteria and ensure the effective implementation of legislation. The paper presents an analysis of how Slovak state administration has converged with EU requirements in the field of sustainable agriculture, land use, forestry and natural resources. Administrative convergence is considered through the internal convergence represented by capacities without legal subjectivity, and through external convergence represented by legal and administrative subjectivity. Both approaches are observed at the central level within specialized public authorities. Local state administration is characterized by the creation of internal administrative capacities with the challenging delimitation of which competences are affected by the process of administrative convergence.     

The rise of thermophilic sea urchins and the expansion of barren grounds in the Mediterranean Sea

Recent ecological studies have shown a strong relation between temperature, echinoids and their grazing effects on macro-algal communities. In this study, we speculate that climate warming may result in an increasingly favourable environment for the reproduction and development of the sea urchin Arbacia lixula. The relationship between increased A. lixula density and the extent of barren grounds in the Mediterranean Sea is also discussed.     

Assessment of the Water Quality of the River Arno in the Area of Florence,Italy

The quality of the waters collected from R. Arno was examined in the period September 1988 to December 1989. A first campaign in September/October 1988, during a period of low water, gives a general picture of pollution conditions along the river from the source to the mouth. the river appears to be heavily polluted immediately downstream of Florence and in the area of the textile industry.

In the second campaign, through the whole year 1989, particular attention has been given to the Florence area; the most significant results, compared with those from a previous investigation carried out in 1971, show only a small reduction of the pollution load, due to the shortage and inadequacy of wastewater depuration. Some considerations are reported on pollution drop with full spate.     

High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: a pilot scale study

The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35°C), thermophilic (55°C) and temperature phased (65+55°C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m(3)d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m(3)d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m(3)d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m(3)/kgVS(fed) at 35, 55, and 65+55°C, respectively. The extreme thermophilic reactor working at 65°C showed a high hydrolytic capability and a specific yield of 0.33 g COD (soluble) per gVS(fed). The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile fatty acids of 20 and 9 g/l, respectively. Acetic and propionic acids were the main compounds found in the acids mixture. Because of the improved digestion efficiency, organic nitrogen and phosphorus were solubilised in the bulk. Their concentration, however, did not increase as expected because of the formation of salts of hydroxyapatite and struvite inside the reactor.     

Ecological and human health risk aspects of burning arsenic-rich coal

The subject of the study was the ecological and human health consequences of environmental pollution from emissions arising from burning local coal with an arsenic content ranging from 900 to 1,500 g/tonne of dry substance. The first indication of environmental pollution by arsenic-containing emissions was the mass extinction of honeybee colonies. The neurotoxic and carcinogenic aspects of arsenic exposure were followed. On using a group diagnostics approach, significant hearing losses were detected in exposed children in both air and bone conduction audiometry at high frequency range (4,000 and 8,000 Hz, respectively). Exposure assessment of the local population of the Prievidza district, Central Slovakia, was based on biological monitoring. The criterion of higher exposure was arsenic content in hair exceeding concentrations of 3 μg/g of hair. In a 7.5-km radius of the exposed region, live about two-tenths of the district population who were considered as “exposed” and rest of the district served as the “reference” population. The subject of our analysis was a database of 1,503 non-melanoma skin cancer (NMSC) cases (756 in men and 747 in women) collected from 1977 to 1996 in the Prievidza district, Central Slovakia (population ~125,000). The age standardized incidence of NMSC (each confirmed by histological examination) in non-occupational settings ranged from 45.9 to 93.9 in men and from 34.6 to 81.4 in women. Analysis of our data demonstrates a positive correlation between human cumulative exposure to arsenic and incidence of NMSC.