A reliable indicator of female fecundity: the case of the yellow belly in<Emphasis Type="Italic"> Knipowitschia panizzae</Emphasis> (Teleostei: Gobiidae)

A large body of research has developed on male ornaments and their role in sexual selection while female ornaments have been less investigated. This study focused on the presence, function, and possible role of a sexually dimorphic nuptial trait as an indicator of female quality in a fish species presenting conventional sex roles: the yellow patch on the belly of Knipowitschia panizzae females. Aquarium spawning experiments demonstrated that this ornament is due to dermal pigments, is displayed only when the female is ready to spawn, and is switched off within minutes from the end of egg deposition. This sexual trait is variable in size among females and indicates female fecundity relative to her own body size. As a consequence, female yellow belly appears to be a reliable indicator of female quality as measured by current fecundity. Field data on natural nests highlights that males usually perform parental care on only one egg batch at a time. The modality of egg deposition suggests that males may be limited in their potential reproductive rates by environmental factors. Male limitations in egg care could favour male choosiness and the evolution of female nuptial displays.Communicated by R. Cattaneo-Vietti, Genova     

Tail beat frequency as a predictor of swimming speed and oxygen consumption of saithe (<Emphasis Type="Italic">Pollachius virens</Emphasis>) and whiting (<Emphasis Type="Italic">Merlangius merlangus</Emphasis>) during forced swimming

Oxygen consumption and tail beat frequency were measured on saithe (Pollachius virens) and whiting (Merlangius merlangus) during steady swimming. Oxygen consumption increased exponentially with swimming speed, and the relationship was described by a power function. The extrapolated standard metabolic rates (SMR) were similar for saithe and whiting, whereas the active metabolic rate (AMR) was twice as high for saithe. The higher AMR resulted in a higher scope for activity in accordance with the higher critical swimming speed (U _crit) achieved by saithe. The optimum swimming speed (U _opt) was 1.4 BL s⁻¹ for saithe and 1.0 BL s⁻¹ for whiting with a corresponding cost of transport (COT) of 0.14 and 0.15 J N⁻¹ m⁻¹. Tail beat frequency correlated strongly with swimming speed as well as with oxygen consumption. In contrast to swimming speed and oxygen consumption, measurement of tail beat frequency on individual free-ranging fish is relatively uncomplicated. Tail beat frequency may therefore serve as a predictor of swimming speed and oxygen consumption of saithe and whiting in the field.     

Prenatal karyotyping in malformed fetuses

Experience with prenatal karyotyping of 237 fetuses with sonographic evidence of malformation is reported. Abnormal karyotype was found in 40 cases (16-8 per cent): chromosomal aberrations were found in 19 of the 178 fetuses with an isolated structural anomaly (10-6 per cent) and in 21 of the 59 fetuses with multiple malformations (35-6 per cent). Detailed cytogenetic and morphological information concerning fetuses affected by omphalocele, duodenal atresia, hydrocephalus, multicystic kidney, unilateral hydronephrosis and cystic hygroma is reported. The need for a very careful ultrasound evaluation of fetal anatomy in these pregnancies is stressed, as the risk of a chromosomal anomaly depends mainly on the existence of more than one ultrasonically diagnosed structural defect.     

Effect of copper in the protistan community of activated sludge

Protists have proved to be an interesting tool for assessing the occurrence of pollution in wastewater treatment systems along with its role in the control of pollution itself through grazing of dispersed bacteria and maintenance of a healthy trophic web in those artificial ecosystems. Two sets of assays were carried on in a bench scale pilot plant in order to study the response of the activated sludge community of protists to the exposure of copper: the first set was carried on with synthetic sewage and the second one with real sewage. The results emphasize the ability of activated sludge biological communities to survive and to react to toxicants and highlight the role of protistan communities as indicators of toxicants entrance in treatment systems.     

Markets,population dynamics,and coastal ecosystems

Our synthesis focuses on how markets influence the population and environment relationship within coastal ecosystems by considering the differential valuing of environmental resources and ecosystem services through 3 perspectives: livelihood, globalization, and public goods and externalities. These are not new perspectives when considering how markets shape demographic and environmental outcomes. However, we suggest that the insight offered by viewing coastal and marine health through these combined lenses brings into focus with renewed urgency the perils facing these vital ecosystems.     

Study of calcium-dependent lead-tolerance on plants differing in their level of Ca-deficiency tolerance

The main aim of the study was to determine the role of calcium in the amelioration of lead toxic effects in plants with accordingly high/low level of Pb-tolerance and high/low Ca-deficiency tolerance. The study was performed on maize, rye, tomato and mustard. Plants were cultivated in modified Knop's solution. They were subjected to Ca-deficiency, and to lead nitrate administered in the presence of four calcium nitrate concentrations 3.0, 2.4, 1.2, 0.3mM. Lead-tolerance and tolerance to Ca-deficiency were determined, as were concentration of the studied elements in plant tissues, and the Pb deposition pattern at the ultrastructural level (electron microscopy study, X-ray microanalysis). In all studied plants, lead toxicity increased as medium calcium content decreased, however, only in the Ca-deficiency sensitive mustard with low Pb-tolerance was it accompanied by a rise in tissue lead concentration. In contrast, lead root and shoot levels did not increase in the highly Ca-deficiency tolerant tomato, mustard and rye with high Pb-tolerance irrespective of the Ca(2+) regimens applied. Thus, in these plants, lead's unfavourable effects resulted only from the higher toxicity of the same amount of lead in tissues at low calcium in the medium. Of particular relevance is the finding by electron microscopy and X-ray microanalysis, that under low calcium in both highly Ca-deficiency tolerant and Ca-deficiency sensitive plants, less efficient Pb(2+) detoxification was accompanied by the restriction of the formation of large lead deposits in cell walls. Obtained results are novel in demonstrating calcium involvement in the lead deposition in the cell wall, thus in the regulation of the internal lead detoxification.     

Hydroxylated PCB metabolites in nonhatched fulmar eggs from the Faroe Islands

Thirty-six polychlorinated biphenylols (OH-PCBs) congeners were characterized in Fulmar (Fulmarus glacialis) eggs collected from the Faroe Islands. The seven most abundant congeners were quantified in 19 samples, and the sigmaOH-PCB concentrations ranged between 0.92 and 4.0 ng g(-1) fresh weight (f.w.). These eggs constitute a part of the traditional diet for at least a part of the population on the Faroe Islands and may contribute to the high levels of these contaminants found in the blood of pregnant Faroese women. Because the metabolites are present in the nonhatched fulmar egg, it is concluded that the OH-PCBs are transferred to the egg before laying. High levels, 3300-18,000 ng g(-1) l.w., of sigmapolychlorinated biphenyls (PCB) were determined in the fulmar eggs, which are a considerable source for human exposure. The high PCB levels are a source for metabolic formation of hydroxylated PCBs.     

Photodegradation of pentachlorophenol and its degradation pathways predicted using density functional theory

The objectives of the present research were (i) to report the mass balance of chlorine during pentachlorophenol (PCP) photodegradation and (ii) to reveal the photodegradation pathway experimentally with a theoretical proof based on the density functional theory (DFT). The chlorine of PCP was completely mineralized to produce chloride ions after 24h of UV irradiation. As intermediates, 2,3,5,6-tetrachlorophenol, 2,3,4,6-tetrachlorophenol and 2,5-dichlorophenol were identified. At least 80% of the chlorine balance during PCP photodegradation was accounted by PCP, these intermediates, and chloride ions. A DFT calculation showed differences in the C-Cl bond dissociation energy level and the positions of respective PCP molecular and the PCP intermediates. The dechlorination intermediates predicted using the calculated C-Cl bond dissociation energy were consistent with those experimentally confirmed, indicating the feasibility of this theoretical method in predicting the dechlorination pathway.     

Investigation of the complexation of metal-ions by strong ligands in fresh and marine water

SCOPE: The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters. OBJECTIVE AND METHOD: It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin. RESULTS: The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals. CONCLUSION: The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free.