Food supplementation affects egg albumen content and body size asymmetry among yellow-legged gull siblings

Parental decisions can determine offspring experience of environmental conditions. Such ‘maternal’ effects act both before and after hatching via, e.g., egg quality or the social milieu predisposed by parents. Resource availability may constrain the expression of adaptive maternal effects, and the specific pattern of allocation of these effects among offspring depending on their sex or birth order can result in different fitness payoffs to parents. Declining egg mass with laying order observed in several bird species may constitute an adaptive strategy of parental favouritism towards early hatching offspring with larger reproductive value but may also result from nutritional constraints on laying effort. A previous study has shown that the small size of the third, last laid (c-)egg in yellow-legged gull (Larus michahellis) clutches depends on food availability and that food-supplemented mothers increase the size of their female but not male c-eggs. Here, we show that increased mass of c-eggs laid by females supplemented with food after clutch initiation depends on increased albumen mass, which, in turn, enhances the size of daughters at hatching. Because asynchronous hatching results in a competitive disadvantage of c-chicks, present results suggest that mothers relieved from nutritional constraints enhance the size of daughters to compensate for their larger susceptibility to hatching last. The study also confirms the role of egg albumen content in determining hatchling size, previously experimentally detected only in one species in the wild. The effect of increased egg mass on offspring size persisted at least until day 8 after hatching, when, however, it did not vary with sex, suggesting intense negative selection on small female c-chicks in control broods. Hence, maternal effects mediated by egg albumen content had persistent effects on offspring size.     

Adenosine nucleotide “energy charge” ratios as an ecophysiological index for microplankton communities

Energy charge (EC) ratios of microplankton samples have been measured from their adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) contents, according to a method based on enzymatic tranformations of ADP and AMP into ATP, and the subsequent quantitative analysis of the latter by the bioluminescent reaction of a firefly lantern extract (Photinus pyralis). Interference caused by other non-adenylic nucleotides and bioluminescence inhibition by various compounds were reduced, or estimated, by the use of internal standards for each sample. This was accomplished both by the injection of a small volume of a non-commercial extract of P. pyralis and by measurement of the bioluminescent flash at its maximal value. This standard method for preparation and analysis afforded good reproducibility and permitted the calibration of individual samples, thus allowing the comparison and treatment of data in the large series necessary in oceanographic studies. Studies were made on natural populations taken from a polluted marine area where phytoplankton communities live under the stressful influence of an urban sewer outlet, near Marseille (France). Three sampling strategies in surface waters (transects from the outlet, sampling during a 24-h buoydrift, and regular sampling for a day-night period) conducted at a point in front of the outlet revealed a decrease of EC in relation to urban activity or approaching proximity of the sewer outlet. These low EC values (0.2 to 0.5) were caused by a high AMP content, perhaps originating from degraded biogenic particles and dead or metabolically impeded bacteria of terrestrial orgin stressed by ecologic factors such as increased salinity and decreased temperature. Further away from the sewage outlet, the EC increased as the bacterial population decreased, and the phytoplanktonic communities reappeared parallel to the dilution of the effluent. Although in mature and unperturbed ecosystems EC values of 0.70 to 0.80 were recorded, the values were generally lower than those measured in growing bacterial or phytoplankton cultures. This fact may be related to differences in the various metabolic states of multispecific populations. Some EC measurements from deeper microplankton samples presented in this paper were difficult to interpret, reflecting perhaps unsolved problems concerning the treatment of samples. However, it was possible to associate the range of variation in EC values to differences in composition and structure of the ecosystem of microplankton populations in neritic surface waters.     

Utilisation des mesures de charge énergétique,d'ETS et de 14C-assimilation pour le suivi de l'activité microplanctonique dans des eaux côtières sous l'influence de rejets urbains

The influence of the sewage from the city of Marseilles, France, upon the marine microplanktonic assemblages was followed over a period of one year (May 1980–April 1981) at five stations and three sampling depths. Measurements of the ¹⁴C assimilation rate, adenylate energy charge, and the electron-transport system (ETS) were compared with parallel phytoplankton and bacteria counts. In the coastal waters near the sewage outlet the phytoplanktonic organisms were stressed, as attested by the low values of both assimilation rate and energy-charge ratios; the living microbiomass in these waters was essentially of bacterial origin. In waters situated 4 to 5 km away from the outlet, and therefore not directly under its influence, higher mean P:B and EC ratios indicated the presence of a predominantly living phytoplanktonic assemblage. Nevertheless, the metabolic stress induced by the inflow of polluted water to the waters near the sewage outlet did not prevent the occurrence of a spring bloom. The electron-transport system measurements and their relationship to the effective bacterial counts are in good accordance with the literature data describing laboratory cultures, and indicate intense heterotrophic activity in the waters nearest to the sewage outlet. This activity is most probably of bacterial origin: perhaps some of the terrestrial germs introduced into the marine environment remained viable, perhaps the considerable volume of organic matter introduced into this area induced heterotrophic development, or perhaps both factors combined. Simultaneous consideration of biochemical and physiological data with the structure and composition of the microplanktonic populations could explain the apparent contradiction between the high level of nutrient supply and the lack of photoautotrophic growth noted in previous studies in this area. However, the considerable amounts of fresh organic matter present in the waters near the sewage outlet at Cortiou indicate the necessity for great care in the use of biochemical parameters such as chlorophyll or AMP for the estimation of microplankton biomass; such estimates can be biased by the presence of non-degraded detrital particles of biological origin.     

Effect of the presence of the shore crab, <Emphasis Type="Italic">Carcinus maenas</Emphasis>, on burrowing behaviour and clearance rate of the common cockle, <Emphasis Type="Italic">Cerastoderma edule</Emphasis>

Bivalves demonstrate various morphological and behavioural adaptations to reduce the risk of being attacked by predators. This paper examines how the presence of the crab Carcinus maenas (L.), a natural predator of the cockle Cerastoderma edule (L.), affects its burrowing depth and clearance or feeding rate. Cockles were placed in experimental tanks and treated with three levels of predatory disturbance: (1) unfed crab loose inside the tank, (2) unfed crab inside a cage suspended in the water column and (3) no crab present. Cockles’ burrowing depth was measured in two sediment types: mud and sand. Cockles burrowed more deeply in treatments with no crabs. Burrowing depth in sand was significantly greater than in mud. Two factors may contribute to the reduction in burial depth of C. edule in the presence of C. maenas: the change in the vertical orientation of the cockle and the ‘cough response’. No significant difference was found in the cockles’ clearance rate among the different levels of predator threat.     

Physicochemical and Antioxidant Properties of White (Fiano cv) and Red (Negroamaro cv) Grape Pomace Skin Based Films

Journal of Polymers and the Environment - Grape pomace, as by-product of wine making, is a source of polyphenols, fibers, fatty acids, metals, and organic acids, which could be used as raw...     

Preparation and characterization of biochar from cement waste for removal of rhodamine B dye

Journal of Material Cycles and Waste Management - Cement waste (CW) is one of the main environmental problems in the cement industry due to the high amount that is used and its incorrect disposal....     

Ag recovery from waste printed circuit boards of cell phone for synthesis of Ag nanoparticles and their antibacterial activity

Journal of Material Cycles and Waste Management - The increase in technology has increased the consumption and waste of electrical and electronic equipment, especially cell phones (smartphones)....